Questions and Answers
What is evolution defined as?
To demonstrate evolution by natural selection, all of the following conditions must be satisfied EXCEPT?
______________ selection favors organisms that have character values at both extremes of the phenotypic distribution.
Disruptive
Which of the following statements is NOT consistent with evolution by natural selection?
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All of the following statements are true about mutations EXCEPT?
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A population is defined as?
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Birth weight in human babies is generally:
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The change in genotypic frequency of a fish population after a flash flood is most likely attributable to?
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Which of the following best explains why genetic bottlenecks and founder effects are evolutionarily important?
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The phenotypic trait of polydactyly, associated with Ellis-van Creveld syndrome, is more commonly found in Old Order Amish populations. What is a possible explanation?
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Study Notes
Evolution and Natural Selection
- Evolution is defined as a change in the frequency of alleles in a population over time.
- Conditions for evolution by natural selection: variation for a trait, heritability of a trait, and differential reproductive success are essential; genetic drift is not required.
- Disruptive selection favors organisms at both extremes of a phenotypic distribution.
Understanding Natural Selection
- Variation among individuals can be inherited, and natural selection can lead to speciation.
- Inherited changes in an organism's lifetime adapting to the environment contradicts natural selection principles.
Mutations and Genetic Variation
- Mutations serve as the origin of genetic variation; they occur as changes in an organism's DNA and are generally random.
- Most mutations are neutral or beneficial; however, the mutation rate is not necessarily affected by radiation exposure.
Population Definitions and Traits
- A population consists of individuals of the same species that live in the same area and have potential for interbreeding.
- Human birth weight is typically subject to stabilizing selection, indicating optimal intermediate weights are favored.
Genetic Drift and Evolutionary Impact
- Significant changes in genotypic frequency in populations, such as after events like flash floods, are often due to genetic drift.
- Genetic bottlenecks and founder effects are crucial in evolution, leading to small populations that are susceptible to genetic drift.
Case Study: Ellis-van Creveld Syndrome
- Polydactyly, associated with Ellis-van Creveld syndrome, is more prevalent in the Old Order Amish; this may suggest a founder effect where a small group of ancestors contributes disproportionately to the gene pool.
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Description
Test your knowledge on the principles of evolution with these flashcards from Chapter 8. Each card includes key definitions and concepts related to evolutionary biology, focusing on allele frequency and morphological traits in populations. Perfect for revision and enhancing your understanding of evolutionary processes.
