Packet 1- Introduction to Biology Notes: pg. 1-2

I. What is Biology? bio= LIFE -ology= STUDY OF, therefore… Biology is the study of life

II. Steps of the Scientific Method To answer a question scientists use many different approaches, yet there are some steps that are common to all approaches:

1. Make an observation Problems are identified by observing and asking questions.

2. Conduct Research Gather information about the thing you plan to change (for biological experiments, this includes learning about the organism you are going to use).

3. Develop a Hypothesis Use the research to make an educated guess It should be in the form of a statement, not a question It must be TESTABLE and you should get results that are MEASUREABLE (not based on opinion). Ex. Changes in temperature cause the color changes in maple leaves. A FORMAL hypothesis is usually in the form of an ‘if….then’ statement. Ex. If a plant is grown under white light, then it will grow more rapidly than a plant under green light.

4. Test your Hypothesis Design and perform an experiment.

5. Record your Data The more information you record, the easier it will be to draw a conclusion. Your data can be recorded in various forms: Quantitative Data = NUMBERS Qualitative Data= WORDS

6. Draw a Conclusion Analyze the data and determine if the data does or does not support your hypothesis. Based upon the data you obtain, you should come to one of the following conclusions: The data did support the hypothesis The data did not support the hypothesis. A conclusion could not be drawn based upon the data that was collected. It is not correct to say that a hypothesis is right or wrong.

7. Replicate or Redo: Conduct the experiment again to show validity of your results or go back to the drawing board…which may mean that you rethink your hypothesis. When possible an experiment should be replicated as many times as possible (3 at the very least). Before you replicate an experiment, you should always be sure that it is designed properly.

III. Parts of an Experiment 1. Independent Variable- is the one thing that the investigator plans to vary or change in the set up of the experiment (also called the manipulated variable). Hint: If I’m the investigator, I change the Independent variable.

2. Dependent Variable- is the variable that the investigator is going to measure (sometimes called the responding variable). Hint: The dependent variable is the data that you record for your results. The independent variable should cause the dependent variable to change (this is called cause and effect relationship, which should be identified within the hypothesis).

Example I want to test to see if the temperature outside affects the number of chirps per minute of a grasshopper. Independent variable= TEMPERATURE Dependent variable= # of CHIRPS PER MINUTE

To make sure that the independent variable (the thing you are changing) is actually causing the change in the test subjects, test subjects are usually divided between two different groups. 3. Experimental Group(s) is the test group. 4. Control Group does not receive the experimental treatment.

Why is the control group in the example so important? It allows you to see if the independent variable is actually causing the change.

Example A drug company has had a breakthrough. They have developed a new diet drug, which they are called The Skinny Pill. After asking for volunteers to try The Skinny Pill, they then secretly place all participants into one of two groups: Those that are in the experimental group are given a pill that contains the diet drug. People in the control group are given a placebo that does not contain any of the diet drug.

5. Standardized Variables (constants)- These are things that are kept the same throughout the setups. In the Skinny Pill experiment, what are some thing you would want to standardize or keep constant? Age range of participants, # of participants in each group, starting weight, overall health, etc.

Hypothesis, Theory, Law. What’s the difference? A. Hypothesis…. A hypothesis is a tentative explanation of a phenomenon. A hypothesis can be refuted (proven wrong) but it cannot be proven correct. However, if a hypothesis is tested again and again and is never falsified, it may become elevated to the level of a theory.

B. Theory… A scientific explanation of an observed phenomenon Have stood the test of time and are accepted as true until proven otherwise

C. Law….. Is a description of an observed phenomenon (but does not try to explain why they happen). A theory will never become a law, and a law never was a theory….Ken Harding

Ex. Law of Superposition- Bottom layers of sediment are older than layers at the top.

Let’s practice what it means to make an inference: Since Darwin was not able to observe the process of evolution, he had to make inferences. These are ideas that come from drawing conclusions based off of previous observations. Let’s practice what it means to make an inference: My fact is that I love candy. What inference can you make from this fact? That because I love candy then I must like all junk food. Fact or Inference? I like candy, therefore I love chocolate. Inference.