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40 Cards in this Set
- Front
- Back
Heterochrony
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Evolutionary change in timing or rate of an organism's development. Used for comparisons of different species. Organism's shape depends in part on relative growth rates of different body parts during development. Changes in rates can alter adult form substantially, leading to evolution of one or more new species.
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Paedomorphosis
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Retention in adult of one or more juvenile features. Eg, Axol-lottle salamander species that grows full size and develops sexual maturity and can reproduce while retaining larval characteristics.
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Allometry
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Relation between size of an organism and the size of its parts. Eg, relation between body size and brain size.
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Homeotic genes
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Master regulatory genes determine basic features, eg, where a pair of legs/wings will develop. Eg, hox genes: provide positional information of a structure in animal embryo. Change in location correlates with conversion of swimming appendages to feeding appendages.
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Exadaptation
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Structures evolve in one context with one function but through time develop another function. Eg, bones that formerly comprised the jaw hinge of early mammals were incorporated into ear region for hearing.
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Taxonomic hierarchy mnemonic device
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King Phillip Came Over From Germany Singing
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Microevolution / Macroevolution
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Micro: Takes place at species level or below.
Macro: Above the species level. |
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Allele
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contrasting gene for the same phenotype
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Phylogeny
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Study of the evolutionary history of the development of a group of organisms compared to other groups of organisms
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Homologous / Analogous structures
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Homologous: structures that are similar in form, shape, structure and function but more importantly share a common embryological ancestor (Eg, wing of bat, flipper of whale)
Analogous: no embryological source (eg, wing of bat and wing of butterfly) |
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Scala Naturae
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Aristotle's Ladder of Nature--species are fixed
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Hutton
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Principle of gradualism (Earth's surface gradually changing)
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Lyell
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"Principle of uniformitarianism" - supported Hutton's gradualism
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Malthus
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"Essay on the Principle of Populations" - Humans are outstripping food sources
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Date: Theory of natural selection
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1838
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Wallace
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theory of natural selection similar to Darwin
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Date: "Origin of Species"
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1859
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Mendel
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Discovered genetics
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Is NS an all-or-none phenomenon?
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No.
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Stabilizing selection
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Involves elimination of individuals with extreme phenotypes. Eg, clutch size in swiss starling
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Disruptive selection
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Increase in the number of individuals with extreme phenotypes, decrease in number of individuals with intermediate phenotypes. Eg, Coho salmon in pacific northwest
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Directional selection
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Increase in number of individuals with an extreme phenotype due to replacement of one allele or more by one or more alleles. Eg, peppered moths
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Intrasexual / Intersexual selection
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Intra: Individuals of one sex of species compete with each for other sex.
Inter: Individuals of one sex act as selection pressure on other sex (women are picky, selection pressure on men) |
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Balanced polymorphism
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Phenotypes are maintained in fairly stable proportions from one generation to the next through time. Eg, terrestrial snail and bird predators
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Cline
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Graded variation in a trait that follows geographic distribution
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Ecotype
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Groups of distinct phenotypes in different habitats that make up a species. Eg, brown bears, bottlenose dolphins
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Convergent evolution
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2 species not closely related evolve similar adaptations or structures because of similar selection pressures.
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Parallelism
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Same as convergent evolution, except species are closely related.
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Divergent evolution
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Populations of organisms isolated from the rest of the species evolve into different species because of selection pressures. Eg, brown bear --> polar bear.
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Allopatric meaning. 2 types
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Different land. Vicariance and dispersal
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Allopatric speciation: vicariance
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Formation of geographical barrier splitting the species
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Allopatric speciation: dispersal
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Group of individuals somehow move to a new habitat and evolve into new species because of selection pressures
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Sympatric speciation. 2 types
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Same land. Ecological isolation and polyploidy
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Sympatric speciation: ecological isolation
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Different resources. Eg, some species of insects
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Sympatric speciation: polyploidy
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Increase in the number of chromosomes beyond the normal diploid number; more common in plants than animals; results from the abnormal movement of chromosomes during meiosis when the gametes are formed. Two types: autopolyploidy and allopolyploidy
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Autopolyploidy
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Individuals of same species
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Allopolyploidy
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Individuals of different species
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Anagenesis
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Species A becomes species B. No increase of number of species.
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Cladogenesis
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Species A becomes species B and C. Increase in number of species.
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Gradualism v. Punctuated Equilibrium
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Gradualism: Speciation is a gradual process and there are intermediates in the formation of a new species.
Punctuated Equilibrium: Speciation is a very fast process with no intermediates. |