Chapter 1: The Study of Life Biology, Fournier, McGraw, Reissfelder, Lance

1.1 Introduction to Biology Objectives: Define biology Identify possible benefits from studying biology Summarize the characteristics of living things Main idea: All living things share the characteristics of life

Biology The science of life When people study living things or pose questions about the environment, they are learning about biology Life flourishes on Earth, and a curiosity about life is a major reason why some people study biology

Biologist The people who study biology They study the structure and function of living things, their history, interactions among environments, and many other aspects of life.

What do Biologists do? They make discoveries and see explanations by performing laboratory and field investigations Study the diversity of life Research disease Develop technologies Technology-the application of scientific knowledge to solve human needs and to extend human capabilities Improve agriculture Preserve the environment

The Characteristics of Life Biologists concluded that all living things have certain characteristics. An organism is anything that has or once had all the characteristics of life. Characteristics of Living Organisms Made of one or more cells Displays organization Grows and develops Reproduces Responds to stimuli Requires energy Maintains homeostasis Adaptations evolve over time

Made of one or more cells All organisms are made of one or more cells The cell is the basic unit of life A bacterium is unicellular – it has just one cell Humans and plants are multicellular – they have many cells

Displays organization The levels of organization (arranged in an orderly way) in biological systems begin with atoms and molecules and increase in complexity Each organized structure in an organism has a specific function Specialized cells – Tissues – Organs - Organ System - Organism

Grows and develops Growth results in an increase in mass in an organism, and in many organisms, the formation of new cells and new structures Development results in different abilities. It is the process of natural changes that take place during the life of an organism

Reproduces Organisms reproduce – produce offspring and pass along traits from one generation to the next If a species is to continue to exist, then members of that species must reproduce Species – a group of organisms that can breed with one another and produce fertile offspring

Responds to stimuli An organism’s external environment includes all things that surrounds it, such as air, water, soil, rocks, and other organisms. An organism’s internal environment is all things inside it A stimulus (plural, stimuli) is anything that is part of either environment and causes some sort of reaction by the organism A response is the reaction to stimulus Being able to respond to the environment is critical for an organism’s safety and survival

Requires energy Energy is required for all life processes Living things need sources of energy to fuel their life functions Examples include: Light energy from the Sun to make food Energy obtained by consuming other organisms

Maintains homeostasis All organisms keep internal conditions stable by a process called homeostasis Homeostasis is the regulation of an organism’s internal conditions to maintain life. Example – Humans perspire to prevent their body temperature from rising too high.

Adaptations evolve over time Adaptations are inherited characteristics that result from changes to a species over time.

Introduction to Biology Describe four characteristics used to identify whether something is alive. Explain why cells are considered the basic unit of living things. List some of the benefits of studying biology. Differentiate between response and adaptation

1.2 The Nature of Science Objectives: Explain the characteristics of science Compare something that is scientific with something that is pseudoscience Describe the importance of the metric system and SI Main idea: Science is a process based on inquiry that seeks to develop explanations

What is science? Science is a body of knowledge based on the study of nature and its physical setting. The nature, or central purpose, of science is scientific inquiry – the development of explanations Scientific inquiry is both a creative process and a process rooted in unbiased observations and experimentation

What is science? (cont.) Uses scientific theory Expands scientific knowledge Challenges accepted theories Questions results Tests claims Undergoes peer review

Uses scientific theory When enough evidence from many related investigations supports an idea, scientists consider that idea a theory. Theory – an explanation of a natural phenomenon supported by many observations and experiments over time Examples of Biological Theories – cell theory and theory of evolution. Based on countless observations and investigations Have extensive supporting evidence Enable biologists to make accurate predictions

Expands scientific knowledge Most scientific fields are guided by research in a constant reevaluation of what is known This reevaluation often leads to new knowledge that scientists then evaluate The search for new knowledge is the driving force that moves science forward

Expands scientific knowledge (cont.) Nearly every new finding causes scientists to ask more questions that require additional research. Examples include Milestones in Biology on p. 12 With pseudoscience, little research is done Pseudoscientific ideas generally do not ask new questions or welcome more research

Challenges accepted theories Scientists welcome debate about one another’s ideas Often, disagreements occur among scientists Then additional investigations and/or experiments are done to substantiate claims Sciences advance by accommodating new information as it is discovered

Questions results Observations or data that are not consistent with current scientific understanding are of interest to scientists These inconsistencies often lead to further investigations With pseudoscience, observations or data that are not consistent with beliefs are discarded or ignored

Tests claims Science-based information makes claims based on a large amount of data and observations obtained from unbiased and carefully controlled investigations and experimentation Conclusions are reached from evidence Pseudoscience often makes claims that cannot be tested These claims often are a mixture of fact and opinion

Undergoes peer review Science-based information is made public and reviewed by scientists’ peers – scientists who are working in the same field of study Peer review – is a process by which, in science, the procedures used during an experiment and the results are evaluated by scientists who are in the same field or conducting similar research. Scientists can repeat the work of others as part of a new experiment

Measurements Scientists use the same system of measurements to repeat experiments The metric system is generally used by scientists when collecting data and conducting experiments The metric system uses units with divisions that are powers of ten The system is called the International Systems of Units known as SI The SI units you will use most often are meter (to measure length), gram (to measure mass), liter (to measure volume) and second (to measure time).

Science in Everyday Life In order to evaluate the vast amount of information available in print, online, and on television, and to participate in the fast-paced world of the 21st Century. Each of us must be science literate. A person who is science literate combines a basic understanding of science and its processes with reasoning and thinking skills Many of the issues that are faced every day relate to the world of biology and involve ethics. Ethics are a set of moral principles or values Ethical issues must be addressed by society based on values it holds important

1.3 Methods of Science Objectives: Describe the difference between an observation and an inference Differentiate among control, independent variable, and dependent variable. Identify the scientific methods a biologists uses for research

Ask a Question Scientific inquiry begins with observation Observation is a direct method of gathering information in an orderly way Scientific inquiry involves asking questions and processing information from a variety of reliable sources After observing, you might combine what you know with what you have learned and begin a process of making logical conclusions called inferences, or inferring.

Scientific methods Biologists use similar methods to gather information and answer questions Even though scientists do not perform scientific methods in the same way each time they conduct an experiment, observing and inferring happen throughout the entire process

Scientific Method (cont.) A problem-solving tool used by scientists to determine the validity of a hypothesis. It is an organized process for finding a solution to a question. Typical eight steps: State the problem Make observations & gather information Form a hypothesis Write down the procedures that will be used to test your experiment Perform an experiment to test the hypothesis Observe, collect and record data. Interpret your results and data. Form a conclusion

Step 1 State the problem in a form of a question. Question – the inquiry or problem relating to a topic that can be answered by conducting an experiment What is it that you are trying to accomplish with your observations and measurements? It is extremely important to begin with a solid problem or question. A good question can be examined, measured and analyzed. Choose a problem that you do not know the answer to and a problem that you can work with.

Step 2 2. Make observations & gather information about what you are studying – research the problem. Research – to conduct an investigation into current information about something. Research can either make or break the project. When doing research, use a wide variety of resources outside of the school library. Research resources: books, library index, newspapers, magazines, science videos, and internet. Scientists rely heavily on the scientific method because there are so many variables to consider and any one of them can affect the results of the experiment. Variables – something that can change or influence the results of an experiment.

Step 3 3. Form a hypothesis Hypothesis – a reasonable assumption based on research about a possible solution or answer to your problem or question. Developing a good, solid hypothesis is the most difficult step of the scientific method. Your hypothesis is the center of your project. The hypothesis will be stated as an if, then, because statement. It is a testable explanation of a situation. If the hypothesis doesn’t make sense, the whole project won’t make sense. When forming the hypothesis, stick with a simple statement, and make it precise and measurable.

Step 4 4. Write down the procedures that will be used to test your experiment. Procedure – a sequence of steps involved in performing an experiment. Detailing the entire experiment and recording analyzed, scientists are able to track the validity of the hypothesis. Writing your procedure will: Help one gather the necessary materials Make sure that the experiment fits the hypothesis that is being tested Help others who want to repeat the experiment

Step 5 Perform the experiment by following the procedure to test the hypothesis. Groups – conditions Control group – are not variables being tested ; remain normal Experimental group – the group that is being tested by changing one variable at a time Variables – the factors that are being tested in the experiment. It is critical that everything in the experiment is the same each time it is tested, except for the one variable that is being tested. Independent variable – the one thing that separates the two groups; the tested factor Dependent variable – the data obtained from the experiment; it results from or depends on changes to the independent variable Constant-a factor that remains fixed during an experiment

Step 6 6. Observe, collect and record data Record – to write accurate information about what occurs during an experiment. While performing an experiment: You may see changes in color, size, texture, odor, weight, movement, shape, etc. Always observe and record the data Data may be quantitative (#) or qualitative (descriptions) Watch your experiment closely and note any reactions that occur Keep results together in one journal or lab book Data may be generated using graphs, charts, and tables Be ethical and honest about the data from the experiment Ethical – following the rules of being fair and honest

Step 7 7. Interpret your data and results Interpret – to explain or give meaning to When interpreting the data, make sure to: Make tables, charts and graphs Draw pictures or take photographs to show the procedure and results Write a summary

Step 8 8. Form a conclusion as to whether the data you collected supports your hypothesis, then you can say that your hypothesis is reliable. Conclusion – the result or outcome of something If the data did not support your hypothesis, then you would have to make new observations and state a new hypothesis. Make sure that it is one you can test. In your conclusion, state: What happened in your experiment? Was it what you expected? Did your results agree with the hypothesis? Did the experiment answer your original question?

Biology Research: An idea to a published article An idea or question forms a hypothesis An experiment tests the hypothesis Data is analyzed from the experiment The analysis and conclusions are reported and published

Serendipity The occurrence of accidental or unexpected but fortunate results. Example: penicillin

Lab Safety Safety symbol is a logo designed to alert you about a specific danger

Fill in the blanks The (1)______ method is one way that people think about and solve questions or problems. When you begin your experiment, it is important to state a problem or (2)_____ that you would like to find an answer to. It is important to look up or (3) _____ up-to-date information about your topic before you conduct any experiments. A(n) (4)_____ is a possible explanation about something. To conduct a(n) (5)_____ is a good way to discover something new about science. Be sure to write down each step or (6)_____ in the correct order before you start your science experiment. When you conduct an experiment and you deliberately change one thing, you are introducing a(n) (7)_____. It is critical to watch or (8)_____ what is happening with every step of your experiment. After you conduct your experiment, a valuable step is to write down or (9)_____ what happened. When you explain what happened in your experiment, you (10)_____ the results. Sharing true information about the outcome of your experiment is an example of (11)_____ behavior. After an experiment, it is important to write down your (12) _____ or summary of what you learned.