Perspectivas evolutivas e comparativas
Introduzido| English | Significado |
|---|---|
| inclusive fitness/ɪnˈkluːsɪv ˈfɪtnəs/ | aptidão inclusiva |
| fixed action pattern/fɪkst ˈækʃn ˈpætn/ | padrão de ação fixo |
A decision before an answer
- A sterile ant works for the colony because her genes are carried by her sisters.
- Your goal: Apply kin selection and inclusive fitness to helping.
Weight help by relatedness
- Kin selection explains helping by inclusive fitness: a gene spreads by aiding relatives who share it. Hamilton's rule says helping pays when rB>C — benefit to the recipient weighted by relatedness exceeds cost to the helper.
- With benefits and costs held equal, closer relatedness makes the inequality more likely to hold: compare siblings (r=.5) with first cousins (r=.125). The rule predicts direction and rough ordering, not exact human behaviour.
Under Hamilton's rule, helping is favoured when:
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The benefit must be weighted by relatedness before comparing with the cost.
Release the fixed pattern
- Ethology studies species-typical behaviour.
- A fixed action pattern is an invariant sequence released by a specific sign stimulus and run to completion, as in classic egg-retrieval or mating displays. Because it is triggered rather than assembled, a fixed action pattern can be hijacked by supernormal stimuli — models with exaggerated features.
A bird courts a painted model with an oversized tail while ignoring real mates. The model works as:
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Exaggerated features of a releasing cue form a supernormal stimulus hijacking a fixed action pattern.
Test the functional story
- Evolutionary explanations ask about function: how a behaviour raised reproductive success in ancestral environments.
- They compete or combine with learning accounts; prepared learning (fast acquisition of evolutionarily relevant fears like snakes) shows both at once. An evolutionary story is a hypothesis about history, and needs comparative or experimental evidence, not plausibility alone.
Helping a sibling before a cousin fits rB>C ordering. A goose retrieving a doorknob as if it were an egg shows a fixed action pattern released by an exaggerated sign stimulus. Acquiring a fear of snakes after one bad experience, but not of flowers, illustrates prepared learning.
Helping a sibling rather than a cousin follows the ordering predicted by ____ selection.
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Inclusive fitness weights aid by relatedness.
Separate the evidence types
- Comparative caution cuts both ways: do not read human motives into animal behaviour (anthropomorphism), and do not assume a human behaviour is learned when cross-species patterns suggest otherwise.
- The examinable skill is matching each explanation to its evidence type.
Treating Hamilton's rule as a precise human calculator, or explaining any observed behaviour as adaptive after the fact; an evolutionary claim needs evidence, not a plausible story.
Qual resposta se encaixa neste caso?
Aplique seleção de kin e aptidão inclusiva para ajudar
A plausible evolutionary story about a behaviour counts as evidence for it.
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Functional accounts are hypotheses about history and need comparative or experimental evidence.
Keep the distinctions
- inclusive fitness 广义适合度 — Reproductive success counting both direct offspring and the reproduction of relatives weighted by relatedness.
- fixed action pattern 固定行为模式 — An invariant species-typical sequence released by a specific sign stimulus.
- Apply kin selection and inclusive fitness to helping.
- Recognise fixed action patterns and sign stimuli in ethology.
- Evaluate evolutionary explanations against learning accounts.
Match each term with its precise meaning in this lesson.
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Keep the distinctions stated in the teaching example.
Put this lesson’s reasoning or event sequence in order.
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The order follows the stated process; check each stage before the next.