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40 Cards in this Set
- Front
- Back
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Speciation
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Formation new species |
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Macroevolution
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Evolutionary changes that produce new species and groups of species |
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Species |
A group of organisms that maintain a distinctive set of attributes in nature; can interbreed |
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Populations in various stages of separation |
-Ecotypes |
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Subspecies |
Cant classify traits somewhat different but not enough can still interbreed |
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Ecotypes |
Populations |
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Characteristics biologist use to identify a species depend on type of organisms |
-Morphological traits -Molecular features -Ecological factors -Evolutionary relationships |
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Reproductive Isolation
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Interbreeding prevented |
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4 main problems with reproductive isolation as the only distinction between species |
-Extinct species -Can be hard to observe -Sometimes they do interbreed, but maintain distinct traits |
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Morphological traits |
-Issues How many traits to consider, continuous variation, and sexual dimorphism |
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Molecular features
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-Compare DNA, genes, chromosomes or proteins |
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Ecological Factors
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-Used for a lot of bacterial species |
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Species Concepts |
-Biological species concept -Evolutionary lineage concept -Ecological species concept -General linage concept |
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Biological Species Concept |
focus on interbreeding |
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Evolutionary lineage concept
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Based on separate ancestral species |
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Ecological species concept |
Based on habitat/ resource use |
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General linage concept |
unifies other ideas; multiple criteria are needed |
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Reproductive Isolating Mechanisms |
-Postzygotic Barriers |
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Prezygotic Barriers
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-Temporal Isolation -Behavioral Isolation -Mechanical Isolation -Gametic Isolation |
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Postzygotic Barriers |
(Not common) -Hybrid Inviability -Hybrid Sterility -Hybrid Breakdown |
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Mechanical Isolation
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Body parts don't match |
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Temporal Isolation |
Different times |
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Habitat Isolation |
Different habitat |
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Behavioral Isolation |
Proper mates |
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Gametic Isolation
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Gametes fail. |
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Cladogenesis
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-Requires reduction in gene flow |
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Allopatric Speciation
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Geographical Isolation Most common type |
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Hybrid Zone |
therefore population not entirely reproductively isolated theres a pass |
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Adapative radiation |
most common on isolated islands |
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Sympatric Speciation |
-Adaptation to local environments -sexual selection -polyploidy -Sexual selection |
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Polyploidy
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Describes organisms with >2 sets of chromosomes plants more tolerant than animals |
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Polyploidy and Speciation
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-new polyploidy can cause immediate isolation -failure to divide after gene duplication -Nondisjunction events (error during mitosis) |
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Gradualism |
Large phenotypic difference due to accumulation of many small genetic changes |
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Punctuated equilibrium
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-Supported by fossil record |
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Evo-Devo
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Developmental genes play large role in pattern formation |
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BMP |
Bone morphogenic protein causes apoptosis takes away webbed |
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Gremlin |
counteracts BMP allows to leave webbed feet |
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Hox genes
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-vary by number & arrangement |
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Heterochrony
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Changes in rate or timing of developmental events |
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Pedomorphosis |
Mature organisms retain juvenile characeristics |
