Introduction to Biology

1. Introduction to Biology Biology = study of life

2. Scientific Method: (6 steps) • Define the problem – usually stated as a question The basis of the scientific method is asking questions and then trying to come up with the answers. You could ask, "Why do dogs and cats have hair?" One answer might be that it keeps them warm. Other examples: (How, What, Which, When, Who, Why, Where?) -- What roach spray is the most effective at killing roaches? -- Why do spiders spin webs? -- What brand of mouthwash kills the most germs? -- Why do birds sing?

3. Researchand Observations – gather background • information

4. 3.Form a hypothesis, make predictions (If…, then…)-Must be testable and measurable ?

5. 4.Test the hypothesis—perform an experiment

6. Controlled Experiment—only one variable is being tested at a time (experimental variable) • Variable—factor in an experiment that can change Example: temperature, time, size, amount or kind of material • Variable that is deliberately changed—manipulated or independent variable (Typically the manipulated or independent variable is also considered to be the experimental variable.) • Variable that changes in response to manipulated variable—responding or dependent variable

7. What could the experimental variable be?

8. Experimental group— contains the variable being tested Control group— does not contain the experimental variable

9. Example: A scientist designs an experiment to see which kind of fertilizer causes the most growth in tomato plants. He tests Scott’s Liquid Grow, Miracle-Gro, and Fertilome Super Grow. He also tests one group of plants that do not receive any fertilizer. All plants are given the same amount of water, sunlight and potting soil. The scientist measures the height of the plants every 2 days for 14 days.

10. Experimental variable = kind of fertilizer Control group = group that received no fertilizer Manipulated (independent) variable = kinds of fertilizer Responding (dependent) variable = plant height

11. 5.Gather and analyze datafrom experiment Data should be gathered from large sample sizes in order to be more representative Ex: Use many tomato plants (100+) when testing for fertilizer b. The closeness of a measurement to the true valueof what is being measured—accurate Ex: Hitting close to or on the bulls eye of a target c. Exact or repeatedmeasurements very close in value—precise Ex: Hitting close to or on the bulls eye of a target multiple times

13. 6.Form a conclusionbased on the data from the experiment If data supports hypothesis—repeat the experiment for verification A hypothesis tested and confirmed often enough that it is unlikely to be disproved becomes a theory If data does not support hypothesis—refine experiment, then repeat experiment

15. Scientific Method Lab