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1、2-,Introduction to Biology,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,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or displ
2、ay.,1-,Why a Study of Biology is Important?,Philosophical Evolution Genetics,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.,1-,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.,1-,Copyright The McGraw-Hill Companies
3、, 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,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.,1-,bahy-ol-uh-jee,Bio = life .ology = the study
4、 of Biology is the science that studies life,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.,1-,The Scientific Method in Action,A systematic way of gaining information,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display
5、.,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?,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduc
6、tion 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 test
7、able,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: Gather
8、ing relevant historical information Retrospective Studies Make additional observations from the natural world Experimentation,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.,1-,The Scientific Method: Experimentation,Experiments rigorous tests to determine i
9、f 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,Copyright The McGraw-Hill Companies, Inc. Permission required
10、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 Cont
11、rol group: variable is not altered, dependent variable Experiments use models to recreate occurrences, but in a controlled setting model organisms, ISS, cohorts,Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display.,1-,Experimental Design,Experiments must: use lar
12、ge 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,Copyright The McGraw-Hill Compani
13、es, 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 infectiou
14、s 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,Copyright The McGraw-Hill Companies, Inc. Permission required for reproductio
15、n 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
16、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.,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
