The Science of Biology 2.2

Review 1. Biology is the scientific study of _________ 2. A data set that uses descriptive words is referred to as ________________data. 3. A data set that uses numeric information is referred to as _________________data. 4. Measurements of a child’s growth for several years would represent _____________data

Hypothesis-Based Science is a Search for Explanations Methods of Hypothesis-Based Science. Figure 2-10 on page 30 illustrates the components of the scientific method: Observation, question, hypothesis, prediction, test

The Components of the Test An experiment will include the following: Background Information A Purpose A List of Materials A Procedure Data table or representation Conclusion

It is true that the work of scientists generally begins with making observations and asking questions.

Forming and Testing a Hypothesis What is a research question? The question being asked and answer sought in an experiment. It should be specific and testable. What is the definition of hypothesis? A suggested answer to a well-defined scientific question.

What is the definition of an experiment? An operation or procedure carried out under controlled conditions in order to discover an unknown effect or law. To test or establish a hypothesis or to illustrate a known law.

A Case Study of Hypothesis-Based Science “From Observations to questions and hypotheses” What are the observations listed in this paragraph? Many poisonous animals are brightly colored There are mimics who look like they’re poisonous but are harmless

What is the given hypothesis? Mimics benefit because predators confuse them with the actual harmful species.

Testing a Prediction of a Hypothesis What is the prediction? Predators will attack snakes with bright rings less frequently than those lacking coloration. What were the materials needed for the experiment? 2 types of artificial snakes, colored and plain brown

What did the researchers do? 1) placed equal #s in various sites 2)Retrieved them after a certain time 3) counted how many had been attacked

Why did the experiment include artificial snakes that were plain brown along with the ringed snakes? The contrast in coloration was necessary to see if predators attack snakes based on their color. The change in color was known as the manipulated variable

What is the definition of a controlled experiment, or otherwise known as experimental control? An experiment that tests the effect of a single variable.

What is the definition of a controlled variable? A variable not changed during an experiment. In the snake experiment, what was the experimental group? Snakes with colored rings. What was the control group? The brown snakes. They were untreated.

Organizing Data and Interpreting Results Define manipulated variable (independent variable) The variable that is altered. In snake experiment: snake color Define responding variable (dependent variable) That which is measured, changed… In snake experiment: # of attacks