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