Evolution

Front 1

Fitness

Back 1

measured in terms of reproductive success and the relative genertic contribution of an individual to the future of the population

Front 2

Natural Selection

Back 2

- chance variations occur thanks to mutation and recombination
- if the variation is "selected for" by the environment, that individual will be more "fit" and more likely to survive to reproductive age
- survival of the fittest leads to an increase of those favorable genes in the gene pool

Front 3

homologous structure

Back 3

similar in structure and share a common evolutionary origin

Front 4

analogous structure

Back 4

share a functional similarity but arose from different evolutionary origins

Front 5

vestigial structure

Back 5

remnants of organs that have lost their ancestral functions

Front 6

Hardy-Weinberg equilibrium conditions

Back 6

1. Large population
2. No mutations
3. Mating is random
4. No migration
5. Genes in population are equally successful ar reproducing

Front 7

Calculating:

allele frequency

Back 7

p + q = 1

Front 8

Calculating:

genotypic frequency

Back 8

p2 + 2pq + q2 = 1

Front 9

5 deviations from Hardy-Weinberg

Back 9

1. Natural selection
2. Mutation
3. Assortive mating
4. Genetic drift
5. Gene flow

Front 10

Natural selection

Back 10

genotypes with favorable variations are selected through natural selection, and the frequency of favorable genes increases within the gene pool

Front 11

Mutation

Back 11

Gene mutations change allele frequencies in a population, shifting gene equilibria

Front 12

Assortive Mating

Back 12

Mates not randomly chosen, but selected according to criteria

Front 13

Genetic Drift

Back 13

Regers to changes in composition of gene pool due to chance

Front 14

Gene Flow

Back 14

Migration of individuals between populations will resultin a loss or gain of genes

Front 15

Three different modes of natural selection

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1. stabilizing selection
2. directional selection
3. disruptive selection

Front 16

Stabilizing selection

Back 16

reduces the frequency of extreme phenotypes, thereby reducing variation

Front 17

directional selection

Back 17

increase in proportion of individuals with an extreme phenotype
- occurs when organisms must adapt to changing environment

Front 18

disruptive selection

Back 18

favors both phenotypic extremes over intermediates
- leads to existence of two or more phenotypic forms within a population (polymorphism)

Front 19

altruistic behavior

Back 19

benerfits one individual at the expense of another

Front 20

speciation

Back 20

groups that can interbreed freely with each other, but not with membres of another species
- due to reproductive isolation

Front 21

Prezygotic causes for reproductive isolation

Back 21

- temporal isolation
- ecolgical isolation
- behavioral isolation
- reproductive isolation
- gametic isolation

Front 22

Postzygotic causes for reproductive isolation

Back 22

- hybrid sterility
- hybrid instability
- hybrid breakdown

Front 23

temporal isolation

Back 23

breed during different seasons or different times of day

Front 24

ecological isolation

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live in same territory but in different habitats

Front 25

behavioral isolation

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not sexually attracted to each other due to things like pheromones or courtship

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reproductive isolation

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physically incompatible

Front 27

gametic isolation

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intercourse can occur, but fertilization cannot

Front 28

hybrid inviability

Back 28

genetic incompatibilities between two species abort hybrid zygote development, even if fertilization does not occur

Front 29

hybrid sterility

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hybrid offspring are steril, thus incapable of producing functional gametes

Front 30

hybrid breakdown

Back 30

first-generation hybrids are viable and fertile, but secondary-generation are inviable and/or infertile

Front 31

convergent evolution

Back 31

refers to independent development of similar characteristics in two or more lineages NOT sharing a recent common ancestor

Front 32

divergent evolution

Back 32

regers to independent development of dissimilar characteristics in two or more lineages sharing common ancestry

Front 33

parallel evolution

Back 33

regers to the process whereby related species evolve in similar ways for a long period of time in response to analogous environmental selection process