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Chapter 23 (terms (terms for gene selection (Relative fitness: individual…
Chapter 23
terms
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Genetic drift: event that causes a change in gene flow, change caused by environmental change (ex. Forest fire)
Founder effect: gene that becomes favourable in a larger group takes over in a smaller group (ex. Settlers on an island, trait for skin color, small population all now have the same skin color)
Bottleneck effect: population shrinks and because of that a trait becomes favourable because it's the most prevalent. Less genetic variation
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terms for gene selection
Relative fitness: individual effect on a gene pool, if you are able to pass on genes “ability to pass on genes”
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Intrasexual selection: competition in between same sex induvidulas for the right to mate with the opposite sex. Males fight for sex
Intersexual selection: females (most commonly) that are choosy in the traits their males counterparts have. Females choose males for sex
Balancing selection: two traits that are different (usually two different colours) that are desirable
Frequency dependent selection: frequency of a phenotypic trait determines how favorable. Rare traits don’t get passed on
genetic variation
populations evolve, not individuals
how evolution progresses
Desirable traits can only come about through existing variation, new alleles don’t arise from nothing
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Chance, selection, and the environment interact
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Chapter 22
terms
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Natural selection: a process whereby desirable traits are passed down (such as strength or intelligence) and because of those traits the species survives
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Strata: layers of rock that, over millions of years, have compressed themselves.
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Homologous: similar make up because of common ancestry Ex: dogs and whales skeletons and internal organs
Vestigous: features that once may have served a purpose that no longer have much use. Ex: appendix for humans, snake pelvis.
Convergence: non similar ancestry, similar traits
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evolution
roots
Hunts proposal of gradualism, Lamarck proposal of “evolution” and “adaptation”
Others: aristotle “ species don’t change over time”, Linnaeus father of classifying organisms / binomial naming system, Malthus population growth
Darwin publishes his observations after a friend says he wants to use his findings in his OWN paper.
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environment
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The patterns is environment demands change, population has variation, favorable traits survive, evolution continues
Chapter 24
24.2
speciation
Sympatric isolation: speciation: formation of new species in the course of evolution behavioral or temporal iso stops the now two distinct species from mating
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chromosomal variation
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Allopolyploid: more than 2 chromosomes and its from two different species. Causes: nondisjunction of chromosomes during mitosis or meiosis
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spaciation rates
punctuated equilibrium: a theory of evolution holding that evolutionary change tends to be characterized by long periods of stability, with infrequent episodes of very fast development (ex. Periods of fit specimens and then there is a forest fire)
gradualism: in evolutionary biology, belief that evolution proceeds at a steady pace, without the sudden development of new species or biological features from one generation to the next (ex. Evolution over millions of years in the ocean)
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