The Science of BiologyCh 2

I. Science is Based on Inquiry and Observations

• Science = A way to answer questions about the natural world

• Starts with asking questions and making observations

• Uses the scientific method

II. The Scientific Method

• Observing and asking questions →make inference→ hypothesis → experiment→ analysis→ conclusion

• Observation :– act of noticing things in nature

Ex: many nonpoisonous snakes mimic the bright coloration of poisonous snakes

• Question: based on observations

• Why do nonpoisonous snakes mimic poisonous ones?

• Inference:– logical interpretation of the question

Mimicry protects the nonpoisonous snakes

• Hypothesis:– Educated guess or possible answer to a question.

Based on observation. Has not been tested yet.• If mimicry protects the snakes, then fewer

colorful nonpoisonous snakes will be attacked than noncolorful nonpoisonous snakes 

• Experiment– Designed to test hypothesis – A controlled experiment has only one variable

being tested or manipulated, the independent variable

• Independent variable: the variable that you are changing

• Dependent variable is what is being measured or observed (the effect)

• all other variables in the experiment should be kept unchanged.

• Some experiments have a positive control and a negative control – Positive control: – Negative control:

• Analysis of data: record of observations• Tables • Graphs • Written observations • Drawings

• Conclusions • Summarizing the data collected• Prove or disprove hypothesis • If hypothesis is disproved did experiment

fail?

• Theory: A hypothesis tested MANY times and proven true. However it could eventually be proven false

•  • Law: a hypothesis that can NEVER be proven

false