As you come in, please:

• Get out a sheet of paper and put your name on it.

• Write a definition, from your own memory, for these terms: hypothesis, scientific law, scientific theory, scientific model.

• On the back of the page, draw a picture of scientists doing science. Show some detail: who is working, what they are doing, what they are using.

What is Science?The Nature of Science and Scientific Inquiry

Who is a scientist?

Who is a scientist?

Ecologists

Who is a scientist?

Microbiologists

Who is a scientist?

Taxonomists

Who is a scientist?

Geneticists

Who is a scientist?

Botanists

Who is a scientist?

MolecularBiologists

Who is a scientist?

Zoologists

Science: A Human Endeavor

The Nature of Science

• Science is:

• based on observations and inferences about the natural world.

• a creative human endeavor

• socially embedded.

The Nature of Science

• Science produces:

• Laws

• Theories

• Models

• knowledge that is always tentative (subject to change).

Hypotheses

• A hypothesis

• is a statement that predicts the outcome of an experiment.

• is valid if it is testable, falsifiable, and specific — not if is correct!

• is tested (not “proven”) by scientific inquiry.

Scientific Laws• A scientific law is a description of a

natural phenomenon.

• Laws are based on empirical evidence.

• Examples:

• Mendel’s laws of inheritance.

• The Hardy-Weinberg Law of population genetics.

• Laws may change with new knowledge.

Scientific Theories• A scientific theory is an

explanation of a natural phenomenon.

• Theories are based on empirical evidence.

• Examples:

• The theory of natural selection.

• Cell theory.

• Theories may change with new knowledge

Scientific Inquiry

• The process that creates scientific knowledge is scientific inquiry.

• Inquiry can be:

• Descriptive

• Correlational

• Experimental

Descriptive Studies

• Descriptive studies describe the object of study in detail.

• Characteristic of young sciences.

• Some sciences, such as Astronomy and Taxonomy, rely almost entirely on descriptive studies.

Correlational Studies• Correlational studies describe two

events that occur at the same time, and look for a relationship between the two.

• Many health studies are correlational: they use large databases of health information, and try to answer questions when an experiment would be unethical.

• However, a correlation does not prove a cause.

Experimental Studies• Experimental studies involve

setting up control and experimental groups in order to the effects of one variable on another.

• Experiments can be used to determine cause.

• Experiments are used to test hypotheses (not to “prove” them).