BIOL 214 Terms & Definitions

DNA

A molecule that stores hereditary information in code form

Gene

Segments of DNA that contain the information that molecular machines use to make a product—an RNA or protein—that functions in the organism

Mutation

Any change in DNA. Mutations create new alleles

Allele

Versions of a gene. For example, if the product of a certain human gene affects hair color, one allele may lead to redder hair while another allele leads to browner hair. Different alleles have different variations of the coded information in the gene

Genotype

A listing of the alleles present in an individual

Phenotype

What an individual looks or acts like

Fitness

The ability to produce viable offspring

Natural selection

The process that changes allele frequencies when certain heritable traits are associated with different levels of reproductive success.

Evolution

A change in allele frequencies.

Directional selection

Natural selection that favors an extreme phenotype.

Stabilizing selection

Natural selection that favors the average phenotype in the population and acts against extreme phenotypes.

Adaptation

A heritable trait that increases fitness in a particular environment.

Theory

An explanation or set of hypotheses that attempt to explain a large and pervasive phenomenon, meaning they that tie together a large suite of observations about how the natural world works.

Fitness

The ability to produce viable offspring.

Artificial selection

When humans actively and consciously select which individuals will be the parents of the next generation.