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13 Cards in this Set
- Front
- Back
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Macroevolution
What is it? 3examples? |
-How we go from one species to another
-The large scale evolutionary changes such as ex 1. the appearance of new species 2. genera 3. higher taxonomic levels |
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Speciation
What is it? Starts? |
(new species)
- Macroevolutionary Process -Starts when a population becomes reproductively isolated from others of the species and ends with new species |
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Biological Species Concept
Theorist? States? |
-Earnest Mayr
-A species is one or more groups of individuals that can interbreed & produce fertile offspring |
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Prezygotic (5 parts)
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(before fertilized embryo)
-Prevent Mating 1) Behavioral Isolation - Different activities Ex. Bird Calls, Frog Calls and Firefly Flashes 2) Temporal -Timing of fertilization on is different in species Ex. Cicada (only come up every 13 years) 3) Mechanical -Animal parts & pollinator parts must match 4) Ecological -Different Environment -populations adapted to two different microenvironments in the same habitat -Ex. Red Fox vs. Arctic Fox 5) Gametic Morality -Gametes cannot unite -Gametes of different species have molecular incompatibilities Ex. Different Pollen or Fertilization in Fish |
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Postzygotic
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after embryo
Postzygotic Isolating Mechanisms Genes can lead to 1. Hybrid inviability (embryo death) 2.Sterility 3. Weak Hybrids (uneven alleles ex. mules & ligers |
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3 models of specitation
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allopatric
parapatric sympatric |
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Sympatric Speciation
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Descended From Single Ancestor
-No barrier -Competition for food may be cause of divergence into two species Polyploidy- 3 or more of each type of chromosome numbers Ex. Fern, Flowering Plant, insects, fish, amphibians & reptiles |
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Parapatric Speciation
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(alongside)
Neighboring populations become distinct species while maintaining contact along a common border Ex. Bullock & Baltimore |
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Allopatric Speciation
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-Physical Separation- Population is split
-Speciation in geographically isolated populations -Preventive Barrier Ex. Mountains, Rivers & Oceans -effectiveness varies Ex. Archipelagos (due to colonization and genetic divergence it is in stage of speciation |
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Gradualism
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Evolution takes place slow and steady
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Punctated Equillibrium
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Long Periods of Stasis alternating with breif bursts of fast evolutionary change
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Adaptive Radiation
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Divergence of multiple new species from a single ancestral type in a relatively short time
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Extinction & Causes of Extinction
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Extinction & Causes of Extinction
All members of a species have died Occurs from failure to adapt to environmental change Causes of Extinction 1.) Impact Theory Asteroid 2.)Crustal MovementsChange Climate 3.)Humans |
