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Questions and Answers
What best defines convergent evolution?
What best defines convergent evolution?
Which term describes the similarity between a shark and a dolphin due to convergent evolution?
Which term describes the similarity between a shark and a dolphin due to convergent evolution?
What is the primary significance of the encephalization factor?
What is the primary significance of the encephalization factor?
What accounts for the unique developmental aspects of the primate brain?
What accounts for the unique developmental aspects of the primate brain?
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What is NOT a cost associated with having a larger brain?
What is NOT a cost associated with having a larger brain?
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Which statement best defines homology?
Which statement best defines homology?
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What does taxonomy refer to in biological classification?
What does taxonomy refer to in biological classification?
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What major evolutionary transition occurred with Australopithecines?
What major evolutionary transition occurred with Australopithecines?
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Study Notes
Chapter 6: Key Terms & Ideas
- Convergent Evolution: Similar behaviors/structures in unrelated animals due to adapting to similar environments. Homoplasy is the resemblance of features (e.g., sharks and dolphins).
- Homology: Similarities based on shared ancestry.
- Analogy: Similarities based on function (e.g., human hand and elephant trunk).
- Genetics: The study of inheritance mechanisms, beginning with Mendel and DeVries.
- Linnaeus's Classification System: Species are identified using genus and species names. Genus groups similar individuals, and species groups those who can reproduce fertile offspring.
- Phylogeny: Visual representation of evolutionary relationships, often resembling a family tree.
- Taxonomy: The science of classifying organisms.
Reasons to Study Species
- Understanding Outstanding Features: Comparing species, studying diseases, and brain development.
- Evolutionary History: Understanding species' evolutionary paths.
Two Methods Used to Study Evolution of the Brain
- Endocast: Creating a brain cast from fossil skulls.
- Studying Living Animals: Comparing similar species to ancestral forms.
Studying the Brain In Evolution
- Encephalization Factor: A measure of brain size relative to body size.
- Brain Size Variation: Brain regions developing later (e.g., cortex) enlarge more relative to other areas (e.g., medulla).
- Primate Brain Evolution: Increased cortex size relative to other parts.
- Mammalian and Reptilian Brain Layers: Differences in the number of cortical layers. Mammals have 6, reptiles have 3.
- Hominin Brain Evolution: Accelerated increase in brain size after the chimp-human split. Factors such as tool use, bipedalism, and agriculture contributed to brain growth.
Costs and Benefits of Large Brains
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Costs: Long gestation periods, small birth canals, prolonged parental dependence, and potential harm from mutated genes.
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Benefits: Innovative behavior, tool use, social learning, and group size limitations.
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Social Brain Hypothesis (Dunbar): Group size and brain size are linked, but Miller counters that sexual selection is the more likely driver.
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