INTRODUCTION TO BIOLOGY

I. What is science? A. Science is the process that scientists use to understand the natural world. B. Based on our senses II. What is biology? A. The study of life. What process do we use to learn about science? What process do we use to learn about science? The Scientific Method!

III.The Scientific Method A.State the problem or research question Ex: Does Vitamin C help prevent sickness? B. Gather background information on the problem Why? Why?  Form a hypothesis  Hypothesis – an educated guess based on observation Ex: I think Vitamin C helps prevents sickness because when I take it regularly I don’t get sick.

D. D.Design an experiment to test your hypothesis 3 RULES TO FOLLOW: 1.Have a control a.Control - the group that is not exposed to experimental variable Ex: The group NOT given Vitamin C. 2.Test only one variable a.Variable – Something in an experiment that can be changed Ex: Vitamin C 3.Use as many subjects as possible (30 minimum)

E. E. Record and analyze data Data Table Example Use tables and graphs to visually present your data; this allows you see patterns and draw conclusions 2. Graphing: a. a. Independent variable - factor in experiment that scientist purposely changes; graph on x- axis (Ex: Vitamin C) b. b. Dependent variable – factor in experiment that scientist wants to observe; changes in response to the independent variable; graph on the y-axis (Ex: Amount of times student got sick)

F. Form a conclusion (3 parts) 1. Address your hypothesis  Use your data to support or reject your hypothesis 2. Error analysis  Sources of error that affected your results  Suggestions for future experiments a. Specific changes to eliminate errors b. What improvements would you make? G. Repeat experiment Why? Why?

Designing an Experiment State the Problem Form a Hypothesis Set Up a Controlled Experiment Record Results Analyze Results Draw a Conclusion Publish Results

IV.Developing Theories A. A.After a scientist reports the results of their experiment supporting their hypothesis… 1. 1.Scientific theory explains things or events based on scientific knowledge resulting from many observations and experiments 2. 2.Law is a time-tested concept that makes useful and dependable predictions about the natural world What is an example of a scientific law?

V. Historical Experiments A. Redi’s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat Uncovered jarsCovered jars Several days pass Maggots appearNo maggots appear Responding Variable: whether maggots appear CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.

B. Pasteur’s Test of Spontaneous Generation   Pasteur’s experiment showed that all living things come from other living things Broth is boiled. Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms

CHARACTERISTICS OF LIFE

I. All living things are called organisms. In order to be considered an organism it must be: A.Made of cells  Organization of multicellular organisms cells tissues organism organ system organs

B. B.Capable of reproducing (sexually or asexually) C. C.Based on a genetic code (DNA) that determines organism’s traits and limited lifespan D. D.Able to grow and develop E. E.Need raw materials and energy 1. 1.Metabolism – the breakdown of food into smaller molecules used to carry out life functions F. F.Able to respond to stimuli (internal or external) 1. 1.Stimuli – something that causes a response G. G.Homeostasis - Maintain stable internal environment despite changes in the internal and external environment H. H.Evolve – change over time