Importance of the Scientific Method in Biology

1. Chapter 1 Scientific Method

2. Why is the Scientific Method Important?

3. The Scientific Method • To answer questions, biologists may use many different approaches, yet there are some steps that are common to all approaches. • The common steps that biologists and other scientists use to gather information and answer questions are known as scientific methods. • There are no fixed steps to follow, but scientific investigations generally involve: 1. Making observations/State problem 2. Making a hypothesis 3. Collecting information 4. Forming a theory by proving/disproving hypothesis

4. A hypothesis is an explanation for a question or a problem that can be formally tested. The hypothesis must be tested in some way. • A hypothesis is not a random guess. It comes about through observations, extensive reading, or previous investigations. • Eventually, the hypothesis will be tested through an experiment.

5. An experiment is an investigation that tests a hypothesis by the process of collecting information under controlled conditions. • Some experiments involve two groups: 1.Control group 2.Experimental group • A control is the standard against which results are compared. The control receives no experimental treatment. • The experimental group is the test group that receives experimental treatment.

6. CONTROL EXPERIMENTAL GROUP GROUP No fertilizer Add fertilizer Same sunlight Same sunlight Same amt. water Same amt. water

7. Designing an Experiment • In a controlled experiment, only one condition is changed at a time. • Independent variable=what is tested because it is the only factor that affects the outcome of the experiment. • Dependent variable=resulting condition • Biologists use a variety of tools to carry out an investigation. Ex: beakers, test tubes, petri dishes, thermometers, balances, etc.

8. Control Experimental Group Group What is the independent variable? What is the dependent variable?

9. The information gained from experiments is called data, which can be in numerical form or verbal form. • Data from an investigation may be considered confirmed only if repeating that investigation several times yields similar results. • Results and conclusions are reported in scientific journals, where they are available for examination by other scientists. • A hypothesis that is supported by many separate observations and investigations, usually over a long period of time, becomes a theory.

10. Kinds of Information • Scientific information can usually be classified into one of two main types: 1.Quantitative information 2.Qualitative information • Quantitative=numerical data Ex: graphs, tables, counts, temperatures • Scientists always report measurements in the metric system called the International System of Measurement, commonly known as SI. Ex: meter (length); gram (mass); liter (volume); second (time); Celcius degrees (temperature) • Qualitative=written descriptions

12. Theories & Laws • A theory is an explanation of a natural phenomenon that is supported by a large body of scientific evidence obtained from many different investigations and observations. • Scientists also recognize certain facts of nature, called laws or principles, that are generally known to be true. (Ex: gravity)

13. REVIEW *Identify what kind of research these are: 1. Numerical data ______________ 2. Field study of hunting behavior ______________ 3. Thermometer, stopwatch ______________ 4. Measurements from lab ______________ 5. Purely observational data ______________ 6. Binoculars, tape recorder ______________

14. Scientific Method Song • http://www.youtube.com/watch?v=MV8lSmIo4Achttp://www.youtube.com/watch?v=MV8lSmIo4Ac