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The flashcards below were created by user
ddanthony
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Four Mechanisms of Microevolution
- 1. Mutation- addtion of new alleles to a population through changes in DNA
- 2. Immigration- introduction of new allele or additional copies of existing alleles via members of different populations
- 3. Genetic Drift- changes in frequency of alleles in a population due to random effects
- 4. Selection- changed in frequency of alleles in a population due to differential survival and reproductive sucess of individuals carrying specific alleles
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Euridian
Element that has a great inifinity to to bind to iron, usually comes from surface of extraterrestial sources- indicating major impact event
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Mass Extinction
(Principle of Hierarchial View)
- 5 major mass extinctions have played a significatn role in shaping modern diversity
- ex. KT extinction
- Bolide impact events
- Flood Basal Eruptions- Volcanism
- Eustatic sea-level changes- changing sea level due to Plate tectonics and climate change <-- buggest mechanism for evolution
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Faunal Turnover
(Principle of Hierarchial View)
Comparision of clade diversification can reveal major events in the history of life
- representatives from 3 statistically distinct "Faunal Cohorts" showing patterns of diversification:
- 1. Vendian-Cambrian Fauna
- 2. Cambrian-Palaeozoic Fauna
- 3. Mesozoic-Cenozoic Fauna
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Gambler's Ruin Model
(Principle of Hierarchial View)
- Orgin and extinction of clades can be modeled as a random process
- repeates many times before the "gambler losses"--> total extinction
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Hierachical model of Macroevolution
Patterns of orgin, diversification & extinction of clades can reveal major events in the history of life
- arises through unique, large-scale phenomena
- contingent historical events are important-especially random
- e.g. KT extinction
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Extrapolationist model of Macroevolution
Accummulated effects of microevolution over very long periods of time
- no unique phenomena
- extinction
- evolution is continous adaptations
- e.g. horse
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Macroevolution
Broad scale patterns of change above species level over geological time. Historical contingency determines which lineages persist.
- Cladogenesis(speciation) is the main creative process
- Extinction (lineage sorting) is the main destructive process
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Microevolution
Genetic changed within a population level over ecological time scales; selection determines which traits persist.
- Mutation is the main creative process
- Selection is the main destructive process
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