Openstax Biology - Chapter 19 - Evolution Of Populations

Front 1

adaptive evolution

Back 1

increase in frequency of beneficial alleles and decrease in deleterious alleles due to selection

Front 2

allele frequency

Back 2

rate at which a specific allele appears within a populatio; also known as gene frequency

Front 3

bottleneck effect

Back 3

magnification of genetic drift as a result of natural events or catastrophes

Front 4

cline

Back 4

gradual geographic variation across an ecological gradient

Front 5

directional selection

Back 5

selection that favors phenotypes at one end of the spectrum of existing variation

Front 6

diversifying selection

Back 6

selection that favors two or more distinct phenotypes

Front 7

evolutionary fitness

Back 7

individual’s ability to survive and reproduce; also known as Darwinian fitness

Front 8

founder effect

Back 8

event that initiates an allele frequency change in part of the population, which is not typical of the original population

Front 9

frequency-dependent selection

Back 9

selection that favors phenotypes that are either common (positive frequency-dependent selection) or rare (negative frequency-dependent selection)

Front 10

gene flow

Back 10

flow of alleles in and out of a population due to the migration of individuals or gametes gene pool all of the alleles carried by all of the individuals in the population

Front 11

genetic drift

Back 11

effect of chance on a population’s gene pool

Front 12

genetic structure

Back 12

distribution of the different possible genotypes in a population

Front 13

genetic variance

Back 13

diversity of alleles and genotypes in a population

Front 14

geographical variation

Back 14

differences in the phenotypic variation between populations that are separated geographically

Front 15

good genes hypothesis

Back 15

theory of sexual selection that argues individuals develop impressive ornaments to show off their efficient metabolism or ability to fight disease

Front 16

handicap principle

Back 16

theory of sexual selection that argues only the fittest individuals can afford costly traits

Front 17

heritability

Back 17

fraction of population variation that can be attributed to its genetic variance

Front 18

inbreeding depression

Back 18

increase in abnormalities and disease in inbreeding populations

Front 19

modern synthesis

Back 19

overarching evolutionary paradigm that took shape by the 1940s and is generally accepted today

Front 20

nonrandom mating

Back 20

changes in a population’s gene pool due to mate choice or other forces that cause individuals to mate with certain phenotypes more than others

Front 21

population genetics

Back 21

study of how selective forces change the allele frequencies in a population over time

Front 22

population variation

Back 22

distribution of phenotypes in a population

Front 23

relative fitness

Back 23

individual’s ability to survive and reproduce relative to the rest of the population

Front 24

honest signal

Back 24

trait that gives a truthful impression of an individual’s fitness

Front 25

inbreeding

Back 25

mating of closely related individuals

Front 26

macroevolution

Back 26

broader scale evolutionary changes seen over paleontological time

Front 27

microevolution

Back 27

changes in a population’s genetic structure

Front 28

selective pressure

Back 28

environmental factor that causes one phenotype to be better than another

Front 29

sexual dimorphism

Back 29

phenotypic difference between the males and females of a population

Front 30

stabilizing selection

Back 30

selection that favors average phenotypes