Speciation Time Scales exam Flashcards
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- SpeciationThe process by which one population splits into two distinct species.
- MicroevolutionEvolutionary changes within a species or small group of organisms, especially over a short period.
- MacroevolutionMajor evolutionary changes that occur over long periods, often resulting in the formation of new species.
- Gradual EvolutionA model of evolution which suggests slow, constant changes over time, leading to numerous intermediate forms.
- Punctuated EquilibriumA model of evolution which posits long periods of stasis interrupted by rapid changes, resulting in fewer intermediate forms.
- What does gradual evolution predict about the fossil record?It predicts that the fossil record should contain many intermediate forms showing a smooth transition from one species to another.
- What does punctuated equilibrium predict about the fossil record?It predicts that the fossil record will show fewer intermediate forms, with species appearing to jump from one form to another.
- Stabilizing SelectionA type of natural selection that favors the average individuals in a population and reduces variation.
- Directional SelectionA type of natural selection that favors one extreme phenotype over the mean or other extreme.
- Intermediate FormsFossils or organisms that show the transitional states between an ancestral form and that of its descendants.
- What is the role of stabilizing selection in punctuated equilibrium?It maintains long periods of stasis with little to no evolutionary change.
- What is the role of directional selection in punctuated equilibrium?It drives rapid evolutionary changes during short periods of time.
- How does gradual evolution view the rate of evolutionary change?As slow and relatively constant over time.
- How does punctuated equilibrium view the rate of evolutionary change?As occurring in rapid bursts, separated by long periods of stasis.
- What is an example of gradual evolution in the fossil record?The smooth transition from terrestrial ancestors to modern whales.
- What is an example of punctuated equilibrium in the fossil record?Species appearing to jump from one form to another with few intermediate forms.
- How long are the periods of rapid change in punctuated equilibrium?Tens of thousands to a hundred thousand years.
- Why are intermediate forms less common in the fossil record according to punctuated equilibrium?Because the rapid changes occur over relatively short periods, leaving fewer specimens to be preserved.
- What connects microevolution and macroevolution?Speciation.
- What does the term 'stasis' refer to in punctuated equilibrium?Long periods of little to no evolutionary change.
- What is the significance of intermediate forms in gradual evolution?They provide evidence of slow, continuous evolutionary change.
- What is the significance of rapid changes in punctuated equilibrium?They explain the sudden appearance of new species in the fossil record.
- How does punctuated equilibrium explain the lack of intermediate forms?Intermediate forms existed but were not around long enough to be commonly preserved in the fossil record.
- What is the main difference between gradual evolution and punctuated equilibrium?Gradual evolution involves slow, constant change, while punctuated equilibrium involves long periods of stasis interrupted by rapid change.
- What is the impact of stabilizing selection on biodiversity?It reduces variation and maintains the status quo within a population.
- What is the impact of directional selection on biodiversity?It increases variation by favoring one extreme phenotype, leading to rapid evolutionary change.
- How do gradual evolution and punctuated equilibrium contribute to our understanding of speciation?They provide different models to explain how species adapt and evolve over time.