BIOLOGY: Chapter 1 The Science of Biology

1.1 The Science of Biology “ Science” is basically two things: – A body of knowledge… an accumulation of things we have learned about the universe – A process… an organized way of gathering and analyzing evidence

Goals of science The goal of science is to provide explanations for events in the natural world Learning about science involves understanding what we know, but also means understanding what we DON’T know Uncertainty is part of the scientific process and is limited by our technology and methods

The Scientific Method An organized process used to answer a question Start with a testable hypothesis Repeatable experiments Conclusion must be supported by the data… scientists sometimes overreach their experiments and “jump to conclusions”

The Scientific Method 1. Background research to understand the state of knowledge of the subject before you begin: What is already known about the topic? What types of methodology have been used in similar experiments? *Thorough background research is what makes the “educated guess” educated

The Scientific Method 2. Form a testable hypothesis based on your background research 3. Design a repeatable experiment using the appropriate controls and variables (only manipulate one variable at a time!) 4. Conduct the experiment and record data ~ multiple trials ~ samples size must be appropriate…bigger is better!

The Scientific Method 5. Analyze the data: statistical analysis and graphing (how different is different?!) 6. Form a conclusion: use your data analysis to determine if your hypothesis was supported 7. Report your results: scientific research journals, conferences, etc

Example of a scientific hypothesis Null hypothesis (Ho): The male and female students have the same IQ Alternative hypothesis (Ha): The male and female students have significantly different IQ scores Must use statistical analysis to show “significance”

Example of a scientific hypothesis Control (population): Avg IQ score = 100 Male test group (n=10): Avg IQ score = 101 Female test group (n=10): Avg IQ score = 102 Are these two results truly different? Depends on the sample size and the range… must use statistics to determine, but probably not!

Controls and variables Control group: exposed to the same conditions as the experimental group with the exception of the experimental variable… the control group is the standard against which the experimental groups are compared Independent variable: the condition that is tested (ie the thing you change in the experiment) Dependent variable: the condition that results from changing the independent variable (ie what is observed or measured)

DRY MIX: How to graph results D:dependent variable R: also called the responding variable Y: graphed on the Y axis M: manipulated variable (what you change) I: also called the independent variable X: graphed on the X axis

Writing experimental procedures Must be clearly written so that anyone can follow your instructions Numerical order, like writing a recipe Use sizes, amounts, units of measure Full sentences with punctuation! Include safety procedures, set up and disposal procedures Make sure to include number of trials, sample sizes, etc

Results/discussion Results should be given in both graphs/charts and written form Extensive discussion attempts to make sense of what you found What does the data mean? What kinds of things made sense or not? Problems or other questions that arose?

Conclusions Was your hypothesis supported? Do not overreach the limits of your study The case of the biting dogs…

Recommendations/Future studies Addresses possible solutions to problems you encountered Things you would like to do differently or repeat in a different way “Offshoots”…what other questions did your research raise? This is how most real research is generated! Some researchers work their entire careers on the basis of one original question

Publication/peer review process “Peer reviewed literature” is often very specific to certain disciplines (ie scientific journals) Process involves sending drafts of manuscripts to experts in the field who review it anonymously and make recommendations Edits and revisions are the norm, sometimes very extensive Often takes up to a year or more Helps to keep science “honest” and as correct as possible

1.2 Science in context Attitudes of a good scientist: – Curiosity – Skepticism – Open-mindedness – Creativity

1.2 Science in context Theory: a well-tested explanation that unifies a broad range of observations and hypotheses and enables scientists to make accurate predictions about new situations Theories are based on much EVIDENCE and supported by DATA

Theories vs. laws Theories do not become laws! Laws (such as ideal gas laws or Newton’s laws) are concise and specific descriptions of how some aspect of the natural world is expected to behave in certain situations. Theories are more dynamic and complex. They encompass a greater number of ideas and hypotheses than laws and are constantly fine-tuned through the process of science.

Bias Scientists must make every effort to avoid bias (bias is not scientific!) Bias does creep into science through funding and political issues, but should be seen and confronted The case of the disappearing whales of Prince William Sound…

Exxon Valdez spill Prince William Sound AK 1989

1.3 Studying Life How do biologists determine if something is “living” or “nonliving”? (biotic or abiotic) They must meet certain criteria Some things (VIRUSES!) meet some but not all of the criteria…grey areas exist

Characteristics of Living Things Based on a universal genetic code (DNA) Grow and develop Respond to their environment (stimulus & response) Made up of cells Reproduce (asexually or sexually) Maintain a stable internal environment (homeostasis) Obtain and use energy and materials (metabolism) *Taken as a group, living things evolve.

Three Domains of Life

6 kingdoms of organisms

Biotic vs. Abiotic