What is Science?The Nature of Science and Scientific Inquiry

The Nature of Science

• Science is based on observations and inferences about the natural world (empirical evidence).

• Science is a creative human endeavor that is socially embedded.

• Scientific knowledge is always tentative (subject to change with new knowledge.

• Laws and theories are the products of science.

Hypotheses

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

• An hypothesis may be stated as a null hypothesis; that is, the hypothesis may predict no change.

• Hypotheses are tested by scientific inquiry.

• Tested hypotheses help build scientific knowledge.

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

• Scientific inquiry is the process that results in building scientific knowledge.

• There are three main types of inquiry (scientific studies):

• 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).

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