Holt Modern Biology, Chapter 16 Vocab

Front 1

Microevolution

Back 1

A change in the collective genetic material of a population

Front 2

Bell Curve

Back 2

On a graph of the frequency of some variable, a curve that first rises and then falls and thus forms a symmetric bell-shaped curve

Front 3

Allele Frequency

Back 3

The proportion of gene copies in a population that are a given allele, expressed as a percentage

Front 4

Hardy-Weinberg Principle

Back 4

The principle that states that the frequency of alleles in a poplulation does not change over generations unless outside forces act on the population

Front 5

Population Genetics

Back 5

The study of the frequency and interaction of alleles and genes in populations

Front 6

Gene pool

Back 6

All of the genes of the reproductively active members of a population

Front 7

Phenotype frequency

Back 7

The ratio of individuals with a particular phenotype to the total number of individuals in a population

Front 8

Immigration

Back 8

The movement of an individual or group into an area

Front 9

Emigration

Back 9

The movement of an individual or group out of an area

Front 10

Geneflow

Back 10

The movement of genes into or out of a population due to interbreeding

Front 11

Genetic Drift

Back 11

The random change in allele frequency in a population

Front 12

Sexual Selection

Back 12

An evolutionary mechanism by which traits that increase the ability of individuals to attract or acquire mates appear with increasing frequency in a population; selection in which a mate is chosen on the basis of a particular trait or traits

Front 13

Stabilizing Selection

Back 13

A type of natural selection in which the average form of a trait if favored and becomes more common

Front 14

Disruptive selection

Back 14

A type of natural selection in which two extreme forms of a trait are selected

Front 15

Directional Selection

Back 15

A type of natural selection in which the most extreme form of a trait is favored and becomes more common

Front 16

Speciation

Back 16

The formation of new species as a result of evolution

Front 17

Morphology

Back 17

The study of the structure and form of an organism

Front 18

Biological Species Concept

Back 18

The concept that a species is a population of organisms that can interbreed but cannot breed with other populations

Front 19

Geographic isolation

Back 19

The physical separation of populations due to geographic barriers that prevent interbreeding

Front 20

Reproductive isolation

Back 20

The inability of members of a population to successfully interbreed with members of another population of the same or related species

Front 21

Gradualism

Back 21

A model of evolution in which gradual change over a long period of time leads to biological diversity

Front 22

Punctuated Equilibrium

Back 22

A model of evolution in which short periods of drastic change in species including mass extinctions and rapid speciation , are separated by long periods of little or no change