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Magnet Biology > Evolution > Flashcards

Flashcards in Evolution Deck (44):
1

Oparin and Haldane

suggested first organic molecules came from early atmospheric gases

2

Miller and Urey

confirmed Oparin and Haldan'es theory

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dating of fossils: relative

layers of strata

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dating of fossils: absolute

radiometric dating

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Precrambrian era

90% of Earth's history

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We are in which era?

Cenozoic era

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Spontaneous generation

life from nonllife

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Theory of biogensis

life from life

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Endosymbotic theory

prokaryotes engulfed other prokaryotes to form eukaryotes

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a population of organisms can change over generations if individuals having certain heritable traits leave more offspring than others

Natural Selection

11

trait shaped by natural selection that increases an organism's reproductive success

Adaptation

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change in the genetic composition of a population over time

Evolution

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Microevolution

pertains to evolutionary change within a population

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Hardy-Weinberg Equilibrium

population that is not changing genetically

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Assumptions under Hardy-Weinberg Equilibrium (there are 5)

1. population is large
2. mating is random
3. no migration
4. mutations can be ignored
5. Natural selection is not acting on the population

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Genetic drift

change in the gene pool of small population due to chance

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Gene flow

gain or loss of alleles due to immigration or emigration

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Non random mating

certain individuals are preferred by the opposite sex

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Types of genetic drift:
Bottleneck effect

a change in a populations allele frequencies due to a substantial reduction in a population size
ex-earthquake

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Types of genetic drift:
Founder effect

Colonization of a new location by a small number of individuals and the random change that occurs in a small colony
ex-amish

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Polymorphism: morph

2 or more contrasting phenotypic alleles for a trait
ex: king snake; blood type

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Polymorphism: cline

graded change in inherited traits in geographic continuum

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Heterozygote advantage

promotes variability and larger gene pool

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Endangered species

generally, low variability

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Neutral variability

No apparent selective advantage for reproductive success; not subject to natural selection

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Types of natural selection: stabilizing-

favors intermediate variants

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Types of natural selection: directional-

shifts the phenotype frequency in one direction or another. Acts as one phenotypic extreme. Common during environmental change
Ex-peppered moths

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Types of natural selection: diversifying-

favors both extremes over intermediates

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speciation

change of a species over time into another

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macroevolution

evolutionary change at or above the level of species

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Prezygotic isolating mchanisms

prevent reproductive techniques

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Habitat isolation

one on land, other on water

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Behavioral isolation

different mating songs

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Mechanical isolation

sex organs are incompatible

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temporal isolation

species reproduce during different seasons or times of day

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Postzygotic

fertilization has occurred but hybrid offspring can't reproduce

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Divergent evolution

formation of a new species from new habitat

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Convergant evolution

2 unrelated species in similar niches but geographically far apart, having similar adaptations

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Homologous structure

our arm vs bat arm

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Analogous structure

bee vs bird wing

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Coevolution

Mutualistic relationship between 2 species
ex-flower and pollinator

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Rate of speciation

most evolution proceeds slowly but sometimes a dramatic event occurs

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gradualism

slow change

44

punctuated equilibrium

dramatic event that causes change