Introduction: Biology Today Chapter 1 Introduction: Biology Today

Biology and Society: Biology All Around Us We are living in a golden age of biology. Biology provides exciting breakthroughs changing our culture. Molecular biology is solving crimes and revealing ancestries. Ecology helps us address environmental issues. Neuroscience and evolutionary biology are reshaping psychology and sociology. © 2010 Pearson Education, Inc.

Figure 1.00 Figure 1.0 Biology is everywhere!

THE SCOPE OF LIFE The Properties of Life Biology is the scientific study of life. Life is structured on a size scale ranging from the molecular to the global. Biology’s scope stretches across the enormous diversity of life on Earth. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

c Growth and development d Energy utilization a Order b Regulation c Growth and development d Energy utilization Figure 1.1a Figure 1.1a Some properties of life. (Part one)

e Response to the environment g Evolution f Reproduction e Response to the environment g Evolution Figure 1.1b Figure 1.1b Some properties of life. (Part two)

a Order Figure 1.1ba Figure 1.1ba Some properties of life.

b Regulation Figure 1.1bb Figure 1.1bb Some properties of life.

c Growth and development Figure 1.1bc Figure 1.1bc Some properties of life.

d Energy utilization Figure 1.1bd Figure 1.1bd Some properties of life.

e Response to the environment Figure 1.1be Figure 1.1be Some properties of life.

f Reproduction Figure 1.1bf Figure 1.1bf Some properties of life.

g Evolution Figure 1.1bg Figure 1.1bg Some properties of life.

Video: Seahorse Camouflage Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Life at Its Many Levels Biologists explore life at levels ranging from the biosphere to the molecules that make up cells. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Figure 1.2-1 Biosphere Ecosystems Communities Populations Figure 1.2 Zooming in on life. (Step 1)

Figure 1.2-2 Biosphere Ecosystems Communities Populations Organisms Organ Systems and Organs Tissues Figure 1.2-2 Figure 1.2 Zooming in on life. (Step 2)

Figure 1.2-3 Biosphere Ecosystems Communities Populations Organisms Organ Systems and Organs Molecules and Atoms Organelles Atom Tissues Nucleus Cells Figure 1.2-3 Figure 1.2 Zooming in on life. (Step 3)

Biosphere Figure 1.2a Figure 1.2a Zooming in on life.

Ecosystems Communities Figure 1.2b Figure 1.2b Zooming in on life.

Populations Organisms Figure 1.2c Figure 1.2c Zooming in on life.

Organ Systems and Organs Figure 1.2d Figure 1.2d Zooming in on life.

Tissues Figure 1.2e Figure 1.2e Zooming in on life.

Nucleus Cells Organelles Figure 1.2f Figure 1.2f Zooming in on life.

Atom Molecules and Atoms Figure 1.2g Figure 1.2g Zooming in on life.

Ecosystems Each organism interacts continuously with its environment. Organisms interact continuously with the living and nonliving factors in the environment. The interactions between organisms and their environment take place within an ecosystem. The dynamics of any ecosystem depend on two main processes: Cycling of nutrients Flow of energy Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Figure 1.3 Loss of ECOSYSTEM Inflow heat of light energy energy Consumers animals Chemical energy food Producers plants and other photosynthetic organisms Decomposers in soil Cycling of nutrients Figure 1.3 Figure 1.3 Nutrient and energy flow in an ecosystem.

Cells and Their DNA The cell is the lowest level of structure that can perform all activities required for life. All organisms are composed of cells. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

We can distinguish two major types of cells: Prokaryotic Eukaryotic Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Bacteria have prokaryotic cells. The prokaryotic cell is simpler and smaller and contains no organelles. Bacteria have prokaryotic cells. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Video: Seahorse Camouflage The eukaryotic cell is larger, more complex, and contains organelles. The nucleus is the largest organelle in most eukaryotic cells. Plants and animals are composed of eukaryotic cells. Video: Seahorse Camouflage Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Figure 1.4 Prokaryotic cell (bacterium) Eukaryotic cell Organelles • Simpler structure Smaller DNA concentrated in nucleoid region, which is not enclosed by membrane Lacks most organelles Larger More complex structure Nucleus enclosed by membrane Contains many • types of organelles • Nucleus Nucleoid region Colorized TEM Figure 1.4 Figure 1.4 Two main kinds of cells: prokaryotic and eukaryotic.

All cells use DNA as the chemical material of genes. Genes are the units of inheritance that transmit information from parents to offspring. The language of DNA contains just four letters: A, G, C, T The entire book of genetic instructions that an organism inherits is called its genome. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

The four chemical building blocks of DNA A DNA molecule Figure 1.5 Figure 1.5 The language of DNA.

Genetic engineering and biotechnology have allowed us to manipulate the DNA and genes of organisms. Bacteria can make insulin because a gene for insulin production was transplanted into their DNA. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Figure 1.6 Figure 1.6 DNA technology in the drug industry.

Life in Its Diverse Forms Diversity is the hallmark of life. The diversity of known life includes 1.8 million species. Estimates of the total diversity range from 10 million to over 100 million species. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Grouping Species: The Basic Concept Biodiversity can be beautiful but overwhelming. Taxonomy is the branch of biology that names and classifies species. It formalizes the hierarchical ordering of organisms. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Figure 1.7 Figure 1.7 A small sample of biological diversity

The Three Domains of Life The three domains of life are Bacteria Archaea Eukarya Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Bacteria and Archaea have prokaryotic cells. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Figure 1.8 Kingdom Plantae DOMAIN EUKARYA Kingdom Fungi DOMAIN BACTERIA Colorized TEM Kingdom Animalia DOMAIN ARCHAEA TEM LM Protists (multiple kingdoms) Figure 1.8 Figure 1.8 The three domains of life.

DOMAIN BACTERIA DOMAIN ARCHAEA Colorized TEM DOMAIN ARCHAEA TEM Figure 1.8a Figure 1.8a The three domains of life. (Part 1)

Protists multiple kingdoms DOMAIN EUKARYA Kingdom Plantae Kingdom Fungi LM Kingdom Animalia Protists multiple kingdoms Figure 1.8b Figure 1.8b The three domains of life. (Part 2)

Domain Bacteria Figure 1.8ba Figure 1.8ba The three domains of life. Colorized TEM Domain Bacteria Figure 1.8ba Figure 1.8ba The three domains of life.

Domain Archaea Figure 1.8bb Figure 1.8bb The three domains of life. TEM Domain Archaea Figure 1.8bb Figure 1.8bb The three domains of life.

Kingdom Plantae Figure 1.8bc Figure 1.8bc The three domains of life.

Kingdom Fungi Figure 1.8bd Figure 1.8bd The three domains of life.

Kingdom Animalia Figure 1.8be Figure 1.8be The three domains of life.

Protists multiple kingdoms LM Protists multiple kingdoms Figure 1.8bf Figure 1.8bf The three domains of life.

Protists are generally single celled. Eukarya includes Kingdom Plantae Kingdom Fungi Kingdom Animalia Protists (multiple kingdoms) Protists are generally single celled. Most plants, fungi, and animals are multicellular. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

These three multicellular kingdoms are distinguished by how they obtain food. Plants produce their own sugars and other foods by photosynthesis. Fungi are mostly decomposers, digesting dead organisms. Animals obtain food by eating and digesting other organisms. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

Unity in the Diversity of Life Underlying the diversity of life is a striking unity, especially at the lower levels of structure. For example, all life uses the genetic language of DNA. Biological evolution accounts for this combination of unity and diversity. Student Misconceptions and Concerns 1. Many students enter our courses with a limited appreciation of the diversity of life. Ask any group of freshmen at the start of the semester to write down the first type of animal that comes to mind, and the most frequent response is a mammal. (In my courses, over a 21-year period, more than 98% of the examples have been mammals.) As the diversity of life is explored, the common heritage of biological organization can be less, and not more, apparent. The diverse forms, habits, and ecological interactions overwhelm our senses with differences. Emphasizing the diversity and unifying aspects of life is necessary for a greater understanding of the evolutionary history of life on Earth. 2. We live in a world that is largely understood by what we can distinguish and identify with our naked senses. However, the diversity of life and the levels of biological organization extend well below the physical scale of our daily lives. For many students, appreciating the diversity of the microscopic world is abstract, nearly on par with an understanding of the workings of atoms and molecules. A laboratory opportunity to examine the microscopic details of objects from our daily lives (the surface of potato chips, the structure of table salt and sugar, the details of a blade of grass) can be an important sensory extension that prepares the mind for greater comprehension of these minute biological details. Teaching Tips 1. Consider asking students to bring to class a page or two of some article about biology that appeared in the media in the last month. Alternatively, you could have each student email a Web address of a recent biology-related news event to you. You might even have them e-mail relevant articles to you for each of the main topics you address throughout the semester. 2. The scientific organization Sigma Xi offers a free e-mail summary of the major science news articles each weekday. The first paragraph or so of each article is included in the e-mail with a hyperlink to the source of the entire article. The topics are most diverse and can be an excellent way to be aware of daily scientific announcements and reports. Typically, about ten articles are cited in each weekday email. To sign up for this free service, go to (www.americanscientist.org/). 3. For a chance to add a little math to the biological levels of organization, consider calculating the general scale differences between each level of biological organization. For example, are cells generally 5, 10, 50, 100 times more massive than organelles? Are organelles generally 5, 10, 50, 100 times more massive than macromolecules? For some levels of organization, such as ecosystems, communities, and populations, size/scale differences are perhaps less relevant and more problematic to consider. However, at the smaller levels, the sense of scale might enhance an appreciation for levels of biological organization. 4. Help the class think through the diverse interactions between an organism and its environment. In class, select an organism and have the class develop a list of environmental components that interact with the organism. This list should include living and nonliving categories. 5. The U.S. Census Bureau maintains updated population clocks that estimate the United States and world populations (www.census.gov/main/www/popclock.html). If students have a general idea of the human population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the current population of the United States is more than 306,000,000 (2008). It is currently estimated that at least one million people in the United States are infected with HIV. The number of people infected with HIV is impressive and concerning, but not perhaps as meaningful as the realization that this represents one of at least every 300 people in the United States. Although the infected people are not evenly distributed amongst geographic and ethnic groups, if you apply this generality to the enrollments in your classes the students might better understand the tremendous impact of HIV infection. 6. The authors make an analogy between the four bases used to form genes and the 26 letters of the English alphabet used to create words and sentences. One could also make an analogy between the four bases and trains composed of four different types of railroad cars (perhaps an engine, boxcar, tanker, and flatcar). Imagine how many different types of trains one could make using just one hundred rail cars of four different types. (The answer is 4100.) 7. An excellent introduction to the domains and kingdoms of life is presented at (www.ucmp.berkeley.edu/exhibits/historyoflife.php).

EVOLUTION: BIOLOGY’S UNIFYING THEME The history of life is a saga of a restless Earth billions of years old. Fossils document this history. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Figure 1.9 Figure 1.9 Digging into the past.

Life evolves. Each species is one twig of a branching tree of life extending back over 3 billion years. Species that are very similar, such as brown bears and polar bears, share a more recent common ancestor. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

polar bear and brown bear Giant panda Spectacled bear Ancestral bear Sloth bear Sun bear American black bear Asiatic black bear Common ancestor of polar bear and brown bear Polar bear Brown bear 30 25 20 15 10 5 Millions of years ago Figure 1.10 Figure 1.10 An evolutionary tree of bears.

The Darwinian View of Life The evolutionary view of life came into focus in 1859 when Charles Darwin published The Origin of Species. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Figure 1.11 Figure 1.11 Charles Darwin and blue-footed boobies on the Galápagos Islands.

Figure 1.11a Figure 1.11a Charles Darwin.

Figure 1.11b Figure 1.11b Blue-footed boobies on the Galápagos Islands.

Darwin’s book developed two main points: Descent with modification Natural selection Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Natural Selection Darwin was struck by the diversity of animals on the Galápagos Islands. He thought that adaptation to the environment and the origin of new species were closely related processes. As populations separated by a geographic barrier adapted to local environments, they became separate species. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Darwin’s Inescapable Conclusion Darwin synthesized the theory of natural selection from two observations that were neither profound nor original. Others had the pieces of the puzzle, but Darwin could see how they fit together. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Observation 1: Overproduction and competition Observation 2: Individual variation Conclusion: Unequal reproductive success It is this unequal reproductive success that Darwin called natural selection. The product of natural selection is adaptation. Natural selection is the mechanism of evolution. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Figure 1.12 Population with varied inherited traits Elimination of individuals with certain traits Reproduction of survivors Increasing frequency of traits that enhance survival and reproductive success Figure 1.12 Figure 1.12 Natural selection.

Population with varied inherited traits Elimination of individuals with certain traits Figure 1.12a Figure 1.12a Natural selection.

Reproduction of survivors Increasing frequency of traits that enhance survival and reproductive success Figure 1.12b Figure 1.12b Natural selection.

Observing Artificial Selection Artificial selection is the selective breeding of domesticated plants and animals by humans. In artificial selection, humans do the selecting instead of the environment. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Figure 1.13a a Vegetables descended from wild mustard Wild mustard Cabbage from terminal bud Brussels sprouts from lateral buds Kohlrabi from stem Kale from leaves Broccoli from flower and stems Cauliflower from flower clusters Figure 1.13a Figure 1.13a Examples of artificial selection.

b Domesticated dogs descended from wolves Gray wolves Figure 1.13b Figure 1.13b Examples of artificial selection.

Domesticated dogs Figure 1.13ba Figure 1.13ba Examples of artificial selection.

Gray wolves Figure 1.13bb Figure 1.13bb Examples of artificial selection.

Observing Natural Selection There are many examples of natural selection in action. Galápagos finches change beak size depending upon the size and shape of available seeds. Antibiotic-resistant bacteria have evolved in response to the overuse of antibiotics. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

Darwin’s publication of The Origin of Species fueled an explosion in biological research. Evolution is one of biology’s best demonstrated, most comprehensive, and longest lasting theories. Evolution is the unifying theme of biology. Student Misconceptions and Concerns 1. Students often believe that Charles Darwin was the first to suggest that life evolves; the early contributions by Greek philosophers and the work of Jean-Baptiste Lamarck may be unappreciated. Consider emphasizing this earlier work in your introduction to Darwin’s contributions. 2. Students often misunderstand the basic process of evolution and instead reflect a Lamarckian point of view. Organisms do not evolve structures deliberately or out of want or need. Individuals do not evolve. Evolution is a passive process in which the environment favors one or more variations of a trait that naturally exist within a population. Teaching Tips 1. Many resources related to Charles Darwin are available on the Internet: a. General evolution resources http://evolution.berkeley.edu/ http://nationalacademies.org/evolution/ http://ncseweb.org/ b. The complete works of Charles Darwin can be found at http://darwin-online.org.uk/ c. Details of Charles Darwin’s home are located at http://williamcalvin.com/bookshelf/down_hse.htm d. An extensive usenet newsgroup devoted to the discussion and debate of biological and physical origins is at www.talkorigins.org/. 2. There are many variations of games that model aspects of natural selection. Here is one that is appropriate for a laboratory exercise. Purchase several bags of dried grocery store beans of diverse sizes and colors. Large lima beans, small white beans, red beans, and black beans are all good options. Consider the beans food for the predatory students. To begin, randomly distribute (throw) 100 beans of each of four colors onto a green lawn. Allow individual students to collect beans over a set period, perhaps 3 minutes. Then count the total number of each color of bean collected. Assume that the beans remaining undetected (still in the lawn) reproduce by doubling in number. Calculate the number of beans of each color remaining in the field. For the next round, count out the number of each color to add to the lawn so that the new totals on the lawn will double the number of beans that students did not find in the first generation. Before each predatory episode, record the total number of each color of beans that have survived in the field. Then let your student predators out for another round of collection (generation). Repeat the process for at least three or four generations. Note what color of beans has been favored by the environment. Apply Darwin’s facts and inescapable conclusions to this exercise. Ask students to speculate which colors might have been favored during another season or on a parking lot. 3. Many websites devoted to domesticated species can be used to illustrate the variety of forms produced by artificial selection. Those devoted to pigeons and dogs have proven to be especially useful.

THE PROCESS OF SCIENCE The word science is derived from a Latin verb meaning “to know.” Science is a way of knowing. Science developed from people’s curiosity about themselves and the world around them. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Discovery Science Science seeks natural causes for natural phenomena. This limits the scope of science to the study of structures and processes that we can observe and measure. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Verifiable observations and measurements are the data of discovery science. In biology, discovery science enables us to describe life at its many levels. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Figure 1.14a Figure 1.14a Careful observation and measurement: the raw data for discovery science.

Figure 1.14b Figure 1.14b Careful observation and measurement: the raw data for discovery science.

Discovery science can lead to important conclusions based on a type of logic called inductive reasoning. An inductive conclusion is a generalization that summarizes many concurrent observations. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Hypothesis-Driven Science As a formal process of inquiry, the scientific method consists of a series of steps. The key element of the scientific method is hypothesis-driven science. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

A hypothesis is a proposed explanation for a set of observations—an idea on trial. Once a hypothesis is formed, an investigator can use deductive logic to test it. In deduction, the reasoning flows from the general to the specific. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

In the process of science, the deduction usually takes the form of predictions about experimental results. Then the hypothesis is tested by performing an experiment to see whether results are as predicted. This deductive reasoning takes the form of “If…then” logic. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Figure 1.15-1 Prediction: If I replace the batteries, the flashlight will work. Question: What’s wrong with my flashlight? Hypothesis: The flashlight’s batteries are dead. Observation: My flashlight doesn’t work. Figure 1.15-1 Figure 1.15 Applying the scientific method to a common problem. (Step 1)

Figure 1.15-2 Prediction: If I replace the batteries, the flashlight will work. Question: What’s wrong with my flashlight? Hypothesis: The flashlight’s batteries are dead. Experiment: I replace the batteries with new ones. Observation: My flashlight doesn’t work. Experiment supports hypothesis; make additional predictions and test them. Figure 1.15-2 Figure 1.15 Applying the scientific method to a common problem. (Step 2)

Figure 1.15-3 Experiment does not support hypothesis; revise hypothesis or pose new one. Revise Prediction: If I replace the batteries, the flashlight will work. Question: What’s wrong with my flashlight? Hypothesis: The flashlight’s batteries are dead. Experiment: I replace the batteries with new ones. Observation: My flashlight doesn’t work. Experiment supports hypothesis; make additional predictions and test them. Figure 1.15-3 Figure 1.15 Applying the scientific method to a common problem. (Step 3)

The Process of Science: Is Trans Fat Bad for You? One way to better understand how the process of science can be applied to real-world problems is to examine a case study, an in-depth examination of an actual investigation. © 2010 Pearson Education, Inc. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Dietary fat comes in different forms. Trans fat is a non-natural form produced through manufacturing processes. Trans fat Adds texture Increases shelf life Is inexpensive to prepare Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

A study of 120,000 female nurses found that high levels of trans fat nearly doubled the risk of heart disease. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

A hypothesis-driven study published in 2004 Started with the observation that human body fat retains traces of consumed dietary fat. Asked the question: Would the adipose tissue of heart attack patients be different from a similar group of healthy patients? Formed the hypothesis that healthy patients’ body fat would contain less trans fat that the body fat in heart attack victims. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

The researchers set up an experiment to determine the amounts of fat in the adipose tissue of 79 patients who had a heart attack. They compared these patients to the data for 167 patients who had not had a heart attack. This is an example of a controlled experiment, in which the control and experimental groups differ only in one variable—the occurrence of a heart attack. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

The results showed significantly higher levels of trans fat in the bodies of the heart attack patients. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Trans fats in adipose tissue g trans fat per 100 g total fat 2.0 1.77 1.48 1.5 Trans fats in adipose tissue g trans fat per 100 g total fat 1.0 0.5 Heart attack patients Control group Figure 1.16 Figure 1.16 Levels of trans fat.

Theories in Science What is a scientific theory, and how is it different from a hypothesis? A theory is much broader in scope than a hypothesis. Theories only become widely accepted in science if they are supported by an accumulation of extensive and varied evidence. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Scientific theories are not the only way of “knowing nature.” Science and religion are two very different ways of trying to make sense of nature. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

The Culture of Science Scientists build on what has been learned from earlier research. They pay close attention to contemporary scientists working on the same problem. Cooperation and competition characterize the scientific culture. Scientists check the conclusions of others by attempting to repeat experiments. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Figure 1.17 Figure 1.17 Science as a social process.

Science, Technology, and Society Science and technology are interdependent. New technologies advance science. Scientific discoveries lead to new technologies. For example, the discovery of the structure of DNA about 50 years ago led to a variety of DNA technologies. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Technology has improved our standard of living in many ways, but it is a double-edged sword. Technology that keeps people healthier has enabled the human population to double to nearly 7 billion in just the past 40 years. The environmental consequences of this population growth may be devastating. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Figure 1.18 Figure 1.18 DNA technology and the law.

Evolution Connection: Evolution in Our Everyday Lives Antibiotics are drugs that help fight bacterial infections. When an antibiotic is taken, most bacteria are typically killed. Those bacteria most naturally resistant to the drug can still survive. Those few resistant bacteria can soon multiply and become the norm and not the exception. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Antibiotics are being used more selectively. The evolution of antibiotic-resistant bacteria is a huge problem in public health. Antibiotics are being used more selectively. Many farmers are reducing the use of antibiotics in animal feed. Student Misconceptions and Concerns 1. Contrasting the concept of faith with the tentative nature of science can help to define and distinguish science from other ways of knowing. Students sometimes enter science classes expecting absolutes of facts and rigid dogma. Instead, scientific knowledge is tentative, reflecting degrees of confidence closely correlated to the strength of the evidence. 2. The authors’ distinction between natural and supernatural explanations is essential to understanding the power and limits of scientific explanations. Teaching Tips 1. Consider using a laboratory exercise to have your students plan and perhaps conduct investigations using discovery science and a hypothesis-driven approach. Emphasize the processes and not the significance of the questions. Students can conduct descriptive surveys of student behavior (use of pens or pencils for taking notes, use of backpacks) or test hypotheses using controlled trials. Students may need considerable supervision and advice while planning and conducting their experiments. 2. Consider presenting your class with descriptions of several scientific investigations that you have written. Include in your descriptions numerous examples of improper methodology (small sample size, several variables existing between the control and experimental groups, failure to specifically test the hypothesis, etc.). Let small groups or individuals analyze the experiments in class to identify the flaws. This critical analysis allows students the opportunity to suggest the characteristics of good investigations in class. 3. Have your students explain why a coordinated conspiracy promoting a specific idea in science is unlikely to succeed. Have your students describe aspects of science that would check fraudulent or erroneous claims and/or political efforts. 4. The authors of Campbell Essential Biology note that the discovery of the structure and functions of DNA has led to a variety of DNA technologies. This technology is discussed in detail in Chapter 12.

Colorized SEM Figure 1.19 Figure 1.19 Natural selection in action.

Figure 1.19a Figure 1.19a Natural selection in action.

Colorized SEM Figure 1.19b Figure 1.19b Natural selection in action.

Growth and development Order Regulation Energy utilization Response to the environment Reproduction Evolution Figure UN1-1 Figure 1.UN1 Summary: Properties of life

Life Prokaryotes Eukaryotes Plantae Fungi Animalia Protists Three kingdoms Domain Bacteria Domain Archaea Domain Eukarya Figure UN1-2 Figure 1.UN2 Summary: The three domains of life

Unequal reproductive success natural selection Observations Conclusion Overproduction and competition Unequal reproductive success natural selection Individual variation Figure UN1-3 Figure 1.UN3 Summary: Natural selection through logical inference

Revise and repeat Observation Question Hypothesis Prediction Experiment Figure UN1-4 Figure 1.UN4 Summary: Steps of the scientific method

complete maze min Average time to 1 2 3 4 5 6 Day 25 20 complete maze min Average time to 15 Key 10 No reward Food reward 5 1 2 3 4 5 6 Day Figure UN1-5 Figure 1.UN5 Question 11: Results of mice in maze experiment