Chp 22-20 Vocab

Front 1

Adaptive Radiation

Back 1

Evolution of several different forms of an unspecialized ancestor

Front 2

Allele frequency

Back 2

Measure of the occurrence of an allele in a population expressed as a proportion. .84 (84%)

Front 3

Allopatric Species

Back 3

Differentiation of geographically isolated populations into distinct species

Front 4

Assortive Mating

Back 4

Type of non random mating where phenotypically similar individuals mate more frequently

Front 5

Behavorial Isolation

Back 5

Evolutionary mechanism thays helps members of the same species find each other as proper mates

Front 6

Biological Species Concept

Back 6

Concept that defines species as groups of populations that can interbreed and are reproductively isolated

Front 7

Bottleneck Effect

Back 7

Loss of genetic variability that occurs when a population is reduced drastically

Front 8

Character Displacement

Back 8

Process in which natural selection favors individuals in a species that uses resources not used by other species

Front 9

Convergent Evolution

Back 9

Independent development of similar structures in organisms not directly related

Front 10

Directional Selection

Back 10

Acts to eliminate one extreme from an array of phenotypes

Front 11

Dissortative Mating

Back 11

Nonrandom mating where phenotypically different individuals mate more frequently

Front 12

Disruptive Selection

Back 12

Acts to eliminate rather than favor they immediate type

Front 13

Ecological Isolation

Back 13

Individuals mate in their preferred habitat, therefore they do not meet individuals with different preferences

Front 14

Fitness

Back 14

Genetic contribution of an individual to succeeding generations

Front 15

Founder Effect

Back 15

Where rare alleles and combination of alleles may be enhanced in new population

Front 16

Gene flow

Back 16

Movement of alleles from one population to another

Front 17

Genetic Drift

Back 17

Random fluctuations in allele frequencies over time by chance

Front 18

Generic Variation

Back 18

Difference in alleles of genes found within individuals of a population

Front 19

Genotype

Back 19

Genetic constitution underlying a single trait or set of traits

Front 20

Genotype Frequency

Back 20

Measures the occurrence of a genotype in a population, expressed as a proportion (25% homozygous recessive genotype)

Front 21

Geographic Isolation

Back 21

Population of animals, plants, or other organisms that are separated from exchanging genetic material with other organisms

Front 22

Gradualism

Back 22

View that species change very slowly in ways that may be imperceptible from one generation to the next

Front 23

Hardy-Weinberg Equilibrium

Back 23

Mathematical description of the fact that allele and genotype population in the absence of inter breeding

Front 24

Heterzygote Advantage

Back 24

Situation in which individuals heterozygous for a trait have a selective advantage

Front 25

Hybrid Infertility

Back 25

When hybrid animals can't reproduce

Front 26

Hybrid Inviability

Back 26

Hybrid animal that is biologically unable to grow to health mature adult

Front 27

Industrial Melanism

Back 27

Phase used to describe the evolutionary process in which lightly colored organisms become dark from natural selection

Front 28

Key Innovation

Back 28

Newly evolved trait in a species that allows members to use resources of the environment previously inaccessible

Front 29

Mass Extinction

Back 29

Sudden, sharp decline in the number of species

Front 30

Mechanical Isolation

Back 30

When different species are isolated by mechanisms such as genetalia could have different shape and sizes

Front 31

Microevolution

Back 31

Evolutionary process itself. Evolution within a species also called adaptation

Front 32

Mutation

Back 32

Permanent change in a cells DNA; includes changes in nucleotide sequence, alteration of gene position, loss, or duplication

Front 33

Oscillating Selection

Back 33

Where selection alternately favors one phenotype at one time and a different phenotype at another time

Front 34

Phenotype

Back 34

Realized expression of the genotype; physical appearance of a trait

Front 35

Polymorphism

Back 35

Presence in a population of more than one allele of a gene at a frequency greater than that of newly arising mutations

Front 36

Polyploidy

Back 36

Condition in which one or more entire sets of chromosomes is added to the diploid genome

Front 37

Population Genetics

Back 37

Study of properties of genes in populations

Front 38

Punctuated Equilibrium

Back 38

Hypothesis about the mechanism of evolutionary change proposing that long periods of little or no change are punctuated by periods of rapid evolution

Front 39

Reproductive Isolation

Back 39

Barrier that prevents genetic exchange between species

Front 40

Stabilizing Selection

Back 40

Form of selection in which selection acts to eliminate both extremes from a range of phenotypes

Front 41

Stasis

Back 41

Period of time during which little evolutionary change occurs

Front 42

Subspecies

Back 42

Geographically defined populations within a single species thats has distinctive characteristics

Front 43

Sympatric Species

Back 43

Differentiation of populations within a common geographic area into species

Front 44

Temporal Isolation

Back 44

Prevents species from mating because they breed at different times

Front 45

Vestigial Structure

Back 45

Morphological feature that has no apparent current function and is thought to be an evolutionary relic; example, hip bones of a boa constrictor