1. DO NOW: -Please get an envelope. -Do not open it yet
DO NOW: -Please get an envelope. -Do not open it yet. -Please Review your notes from yesterday until we start.

2. Please open the envelope and arrange the hierarchy from SMALLEST to LARGEST.
Work silently until we discuss – No Cheating!

3. Biosphere—all of the environments on Earth that support life.
What is a hierarchy?
Biosphere—all of the environments on Earth that support life.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 3

4. What is a hierarchy?
Ecosystem—the organisms living in a particular area AND the physical components with which the organisms interact.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 4

5. Community—all the organisms living in a particular ecosystem.
What is a hierarchy?
Community—all the organisms living in a particular ecosystem.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 5

6. What is a hierarchy?
Population—all the individuals of the same species living in a specific area.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 6

7. Life’s hierarchy of organization…
Organism—an individual living thing.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 7

8. Life’s hierarchy of organization…
Organ system—several organs that cooperate in a specific function.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 8

9. Life’s hierarchy of organization…
Organ—a structure that is composed of tissues and that provides a specific function for the organism.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 9

10. Life’s hierarchy of organization…
Tissues—a group of similar cells that perform a specific function.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 10

11. Life’s hierarchy of organization…
Cells—the fundamental unit of life, separated from its environment by a membrane.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 11

12. Life’s hierarchy of organization…
Organelle—a membrane-bound structure that performs a specific function in a cell.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 12

13. Life’s hierarchy of organization…
Molecule—a cluster of small chemical units called “atoms,” held together by chemical bonds.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. 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, or 100 times larger in diameter than organelles? Are organelles generally 5, 10, 50, or 100 times larger 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.
2. The U.S. Census Bureau maintains updated population clocks that estimate the U.S. and world populations on its website at If students have an accurate general idea of the population of the United States, statistics about the number of people affected with a disease or disaster become more significant. For example, the population of the United States is more than 311 million in It is currently estimated that about 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 realizing that the number of people infected represents about one out of every 311 people in the United States. Although the infected people are not evenly distributed among geographic and ethnic groups, if you apply this generality to the enrollments in your classes, the students might better appreciate the tremendous impact of the infection.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 13

14. Objective: Students will be able to (SWBAT) describe the structure of DNA.
NGSS
HS-LS1-1
Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells. 

15. molecule in biology - we will talk about it all year.
Atom
DNA is an important
molecule in biology - we
will talk about it all year.
Figure 1.2_6 Life’s hierarchy of organization (molecule) 15

16. What is a cell?
The cell is life’s fundamental unit of structure and function.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. Here is a simple way to contrast the relative size of prokaryotic and eukaryotic cells. Mitochondria and chloroplasts are thought to have evolved by endosymbiosis (see Chapter 16). Thus, mitochondria and chloroplasts are about the size of bacteria, contained within a plant cell. A figure of a plant cell therefore provides an immediate comparison of these sizes, not side-by-side, but one inside the other!
2. Examples of biological form and function relationships are nearly endless. Those immediately apparent to your students will be easiest to comprehend. Have your students examine (in photos or in specimens) the teeth of various vertebrates. The diet of these animals is implied by the shape of the teeth (sharp teeth in carnivorous cats and blunted molars in a rat). Sliding your tongue over your teeth reveals our omnivorous history, with sharp canine teeth for slicing flesh and flat rear molars well suited for grinding plant material.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 16

17. Cells are life’s fundamental unit of structure and function.
All cells
are surrounded by a membrane
use DNA as their genetic information
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. Here is a simple way to contrast the relative size of prokaryotic and eukaryotic cells. Mitochondria and chloroplasts are thought to have evolved by endosymbiosis (see Chapter 16). Thus, mitochondria and chloroplasts are about the size of bacteria, contained within a plant cell. A figure of a plant cell therefore provides an immediate comparison of these sizes, not side-by-side, but one inside the other!
2. Examples of biological form and function relationships are nearly endless. Those immediately apparent to your students will be easiest to comprehend. Have your students examine (in photos or in specimens) the teeth of various vertebrates. The diet of these animals is implied by the shape of the teeth (sharp teeth in carnivorous cats and blunted molars in a rat). Sliding your tongue over your teeth reveals our omnivorous history, with sharp canine teeth for slicing flesh and flat rear molars well suited for grinding plant material.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 17

18. Cells are life’s fundamental unit of structure and function.
There are two basic types of cells:
Prokaryotic cells and Eukaryotic 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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. Here is a simple way to contrast the relative size of prokaryotic and eukaryotic cells. Mitochondria and chloroplasts are thought to have evolved by endosymbiosis (see Chapter 16). Thus, mitochondria and chloroplasts are about the size of bacteria, contained within a plant cell. A figure of a plant cell therefore provides an immediate comparison of these sizes, not side-by-side, but one inside the other!
2. Examples of biological form and function relationships are nearly endless. Those immediately apparent to your students will be easiest to comprehend. Have your students examine (in photos or in specimens) the teeth of various vertebrates. The diet of these animals is implied by the shape of the teeth (sharp teeth in carnivorous cats and blunted molars in a rat). Sliding your tongue over your teeth reveals our omnivorous history, with sharp canine teeth for slicing flesh and flat rear molars well suited for grinding plant material.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 18

19. Prokaryotic cells Prokaryotic cells -evolved first are simpler, and
are smaller than eukaryotic 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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. Here is a simple way to contrast the relative size of prokaryotic and eukaryotic cells. Mitochondria and chloroplasts are thought to have evolved by endosymbiosis (see Chapter 16). Thus, mitochondria and chloroplasts are about the size of bacteria, contained within a plant cell. A figure of a plant cell therefore provides an immediate comparison of these sizes, not side-by-side, but one inside the other!
2. Examples of biological form and function relationships are nearly endless. Those immediately apparent to your students will be easiest to comprehend. Have your students examine (in photos or in specimens) the teeth of various vertebrates. The diet of these animals is implied by the shape of the teeth (sharp teeth in carnivorous cats and blunted molars in a rat). Sliding your tongue over your teeth reveals our omnivorous history, with sharp canine teeth for slicing flesh and flat rear molars well suited for grinding plant material.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 19

20. Cells are life’s fundamental unit of structure and function.
2. Eukaryotic cells
contain membrane-bound organelles, including a nucleus containing DNA
are found in plants, animals, and fungi.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. Here is a simple way to contrast the relative size of prokaryotic and eukaryotic cells. Mitochondria and chloroplasts are thought to have evolved by endosymbiosis (see Chapter 16). Thus, mitochondria and chloroplasts are about the size of bacteria, contained within a plant cell. A figure of a plant cell therefore provides an immediate comparison of these sizes, not side-by-side, but one inside the other!
2. Examples of biological form and function relationships are nearly endless. Those immediately apparent to your students will be easiest to comprehend. Have your students examine (in photos or in specimens) the teeth of various vertebrates. The diet of these animals is implied by the shape of the teeth (sharp teeth in carnivorous cats and blunted molars in a rat). Sliding your tongue over your teeth reveals our omnivorous history, with sharp canine teeth for slicing flesh and flat rear molars well suited for grinding plant material.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 20

21. Nucleus (membrane- enclosed)
Figure 1.3
DNA (no nucleus)
Prokaryotic cell
Eukaryotic cell
Membrane
Organelles
Nucleus (membrane- enclosed)
Figure 1.3 Contrasting the size and complexity of prokaryotic and eukaryotic cells
DNA (throughout nucleus) 21

22. Cells are life’s fundamental unit of structure and function.
Cells illustrate an important theme in biology:
Structure is related to function.
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. 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 striking distinctions. Emphasizing the diversity and the unifying aspects of life is necessary for a greater understanding of the rich 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 scale of our unaided perceptions. 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. The ability to examine the microscopic details of the world of our students (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. Here is a simple way to contrast the relative size of prokaryotic and eukaryotic cells. Mitochondria and chloroplasts are thought to have evolved by endosymbiosis (see Chapter 16). Thus, mitochondria and chloroplasts are about the size of bacteria, contained within a plant cell. A figure of a plant cell therefore provides an immediate comparison of these sizes, not side-by-side, but one inside the other!
2. Examples of biological form and function relationships are nearly endless. Those immediately apparent to your students will be easiest to comprehend. Have your students examine (in photos or in specimens) the teeth of various vertebrates. The diet of these animals is implied by the shape of the teeth (sharp teeth in carnivorous cats and blunted molars in a rat). Sliding your tongue over your teeth reveals our omnivorous history, with sharp canine teeth for slicing flesh and flat rear molars well suited for grinding plant material.
3. 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 a Web address of a recent biology-related news event to you. You might even have them relevant articles to you for each of the main topics you address throughout the semester.
4. The scientific organization Sigma Xi offers a free summary of the major science news articles appearing each weekday in major U.S. news media. The first paragraph or so of each article is included in the with a hyperlink to the rest of the article. The diverse topics are an excellent way to learn of general scientific announcements and reports. Typically, 5–10 articles are cited in each . To sign up for this free service, go to
© 2012 Pearson Education, Inc. 22

23. What is DNA? All cells contain DNA.
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 23

24. What is DNA? DNA is short for 'deoxyribonucleic acid’.
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 24

25. What is DNA?
The DNA molecule has a “double helix” shape: two long, thin strands twisted around each other like a spiral staircase.
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 25

26. What is DNA? The DNA double helix Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 26

27. What is DNA made of? Made of monomers called nucleotides
Only four different nucleotides make up all DNA and are repeated.
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 27

28. Nucleotides have three parts
Deoxyribose Sugar
Phosphate Group
Nitrogen Bases
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 28

29. The pyrimidines (Thymine & Cytosine) have only one ring of nitrogen base
The purines (Adenine & Guanine) have two rings of nitrogen bases

30. What is DNA made of?
Sugar + phosphate are the “backbone,” like the sides of the ladder
The base pairs are the “rungs” of the ladder
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 30

31. “Base Pairing” A matches with T,
G matches with C.
In DNA, each base has a very specific partner
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 31

32. “Base Pairing” A pairs with T with two H - bonds
G pairs with C with three H-bonds.
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 32

33. How do we know this is true?

34. History Lesson – Fredrick Griffith
Griffith worked with mice.

35. History Lesson – Fredrick Griffith
Concluded bacteria must be alive to pass on the genetic material.
Protein or DNA????

36. History Lesson – Alfred Hershey & Martha Chase
Concluded DNA is the genetic material not proteins

37. History Lesson – Erwin Chargaff
Determined that the number of C = G and A = T

38. History Lesson – Rosalind Franklin and Maurice Wilkins
Took the first X-ray photographs of DNA to assist in determining the shape.
She died at 38 from cancer in She did not receive the Noble Prize. Wilkins had it with Watson & Crick.

39. History Lesson – Watson & Crick
Determined the shape of DNA based on Franklin’s picture and the correct organization with 10 bases per turn.
She died at 38 from cancer in She did not receive the Noble Prize. Wilkins had it with Watson & Crick.

40. DNA as the hereditary material.
The diversity of life arises from differences in DNA sequences.
We all have different DNA sequences – that’s what makes us different!
Student Misconceptions and Concerns
Students likely have heard the terms chromosome, DNA, and gene. But distinguishing between a chromosome and DNA is often difficult for students and defining a gene has been problematic even for scientists. Consider spending additional time to distinguish between these terms and note how our understanding has dramatically changed in the last 60 years.
Teaching Tips
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 caboose). Imagine how many different types of trains one could make using just 100 rail cars of four different types. (The answer is 4100.)
© 2012 Pearson Education, Inc. 40