Bio: Chp. 15 & 16

Front 1

Hutton

Back 1

(1785) published theory saying earth is millions, not thousands, of years old

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Lyell

Back 2

(1833) wrote book on geology and history of the earth (used by Darwin), argued that earth is millions of years old and that the processes shaping it are still at work today

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Lamarck

Back 3

(1809) best known naturalist pre-Darwin, 3 theories: use+disuse (if a trait is used it will be passed down, if its not used it will evolve out); tendency towards perfection (all animals inclining gradually towards perfection, more efficiency); inherited traits (all traits of a parent inherited: evolution can occur in one generation)

Front 4

Malthus

Back 4

(1798) studied human population growth rate, theorized that if population kept expanding at such a rate there would be insufficient resources to sustain us; disease, war, famine, etc. only check

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natural variation

Back 5

natural differences within a species (e.g some cows give more milk than others, some plants have more flowers)

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artificial selection

Back 6

humans using traits of natural variation to modify characteristic to be more useful (e.g. selective breeding)

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struggle for existence

Back 7

all animals competing to survive, fighting for food, resources, etc.

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fitness

Back 8

an organisms ability to survive in its specific habitat

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adaption

Back 9

an inherited characteristic that increases an animal's fitness (chance of survival)

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survival of the fittest (natural selection)

Back 10

animals more fit to their environments survive and reproduce, animal not fit die or leave few offspring

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descent with modification

Back 11

natural selection causes change in inherited characteristics of a population, changes the population; each living species had descended from another over time

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evidence for evolution

Back 12

homologous structures, fossil record, geographical distribution of species, early development

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homologous structures

Back 13

parts of animals that on the outside look different (e.g. bird wing, mammal leg), anatomically are similar, develop from same embryonic tissue

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vestigial organs

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organs or structure that have little or no function but don't evolve out because they don't effect ability to survive

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gene pool

Back 15

all the genetic information of organisms in a given population, has two or more alleles for each inheritable trait

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population

Back 16

group of organisms of the same species in a given area

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relative frequency

Back 17

number of times an allele appears in a gene pool in comparison to other alleles

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main causes of genetic variation

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mutations: changes in DNA (e.g. red estevan); gene shuffling during reproduction of gametes, (crossing over & random chromosome combinations)

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single-gene trait

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trait controlled by one gene, therefore only two possible phenotypes

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polygenic trait

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trait controlled by several genes, many possible phenotypes and genotypes, follows a bell curve

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directional selection

Back 21

organisms at one end of bell curve more fit than others, bell curve shifts as fitter survive and non-fit die

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stabilizing selection

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those at center of curve fitter than either end

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disruptive selection

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those at either end are fitter than center, if enough pressure can cause spilt into two phenotypes

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genetic drift

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chance change in alleles not by natural selection, common in small populations