1. 2- Introduction to Life Science

2. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Why a Study of Biology is Important? Societal Medicine Public Health Worldwide Water Crisis

3. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Why a Study of Biology is Important? Philosophical Evolution Genetics

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5. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1-

6. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Why a Study of Biology is Important? – Personal To be informed Support your cause Make it your life work

7. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- [bahy-ol-uh-jee] Bio = life...ology = the study of Biology is the science that studies life

8. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- The Scientific Method in Action A systematic way of gaining information

9. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- The Scientific Method: Observation An observation is a thoughtful and careful recognition of an event or a fact. The careful observation of a phenomenon leads to a question. – How does this happen? – What causes it to occur?

10. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- The Scientific Method: The Hypothesis Hypothesizing – question an observation – propose possible solutions to questions based on what is already understood about the phenomenon Hypotheses must: – be logical – account for all current information – make the least possible assumptions – be testable

11. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Testing Hypotheses Hypotheses need to be tested to see if they are supported or disproved. – Disproved hypotheses are rejected – Hypotheses can be supported but not proven Ways to test a hypothesis: – Gathering relevant historical information Retrospective Studies – Make additional observations from the natural world – Experimentation

12. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- The Scientific Method: Experimentation Experiments – rigorous tests to determine if the solutions are supported Experiments attempt to recreation an occurrence – tests whether or not the hypothesis can be supported or rejected There are many types of experiments – laboratory, clinical trials, surveys, statistical analyses

13. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Experimental Design All experiments have key elements in common: – Experiments must be controlled this means that all aspects except for one variable must be kept constant usually include any two groups. – Experimental group: variable is altered, independent variable – Control group: variable is not altered, dependent variable – Experiments use models to recreate occurrences, but in a controlled setting model organisms, ISS, cohorts model organismsISS

14. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Experimental Design Experiments must: – use large numbers of subjects and/or must be repeated several times (replication) – be independently reproducible The validity of experimental results must: – be tested statistically chi-squared test for statistical significance – be scrutinized by other scientists peer reviewed

15. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Theory If the hypothesis is supported by ample experimental data, it leads to a theory. A theory may be defined as a widely accepted, plausible general statement about a fundamental concept in science. – The germ theory states that infectious diseases are caused by microorganisms. Many diseases are not caused by microorganisms, so we must be careful not to generalize theories too broadly. – Theories continue to be tested Exceptions identified Modifications made

16. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- A Scientific Law A scientific law is a uniform and constant fact of nature that describes what happens in nature. – An example: All living things come from pre-existing living things. Scientific laws promote the process of generalization. – Inductive reasoning – Since every bird that has been studied lays eggs, we can generalize that all birds lay eggs. Once a theory becomes established, it can be used to predict specific facts. – Deductive reasoning – We can predict that a newly discovered bird species will lay eggs.

17. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- Scientific Communication Data is shared with the scientific community through research articles published in scientific journals. – peer review Scientists present preliminary data at conferences. Scientists collaborate directly by phone and e-mail. e-mail

18. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- A Sample Experiment Scientific American August 2010

19. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. 1- A Sample Experiment Article: Hardt, Marah J. and Safina, Carl. “Threatening Ocean Life from the Inside Out.” Scientific American August 2010: Vol. 303 2. What types of observations were being made? State a hypothesis that was tested. Describe an experiment that was conducted. Discuss a variable that was studied and describe how constants where maintained in the experiment. How was a model system was used to simulate the conditions being studied. How were the complex processes being studied reduced to their simplest parts? What was learned from the experiments?