L11 inclusive fitness theory 2 Flashcards
What is situationism in the context of inclusive fitness?
The idea that social behaviors like cooperation or altruism depend on specific situational contexts—environment, demographics, location, and available strategies—rather than a single kin‐helping rule.
What does context‐dependent altruism imply?
Individuals act altruistically only when the benefits (to relatives or indirectly to themselves) outweigh the costs, which can change with nesting environment, predators, or resource levels.
Give an example of situationism in a bird species.
A bird might feed unrelated chicks if doing so builds future cooperative partnerships or secures territory defense benefits aligned with its inclusive fitness.
What is Hamilton’s geometric approach to relatedness?
A visual/mathematical model showing how genetic relatedness in a population arises from different causes and how individuals are genetically distributed.
What is coancestry and why is it important?
Shared genes through common descent (e.g., siblings r = 0.5); it underlies classic kin‐selection examples like cooperative breeding.
How does selective aggregation create relatedness?
Genotypes that share habitat preferences or behaviors cluster together (e.g., butterflies on certain tree heights), boosting local genetic similarity without close kinship.
Why can selective aggregation mimic kin selection?
Aggregated individuals gain cooperative benefits—like better predator detection—that functionally resemble kin‐selected altruism.
What is genetic recognition?
A mechanism where organisms detect shared alleles or phenotypes in others and preferentially cooperate with them.
What are the three components of the Green Beard effect?
(1) A gene produces a recognizable trait, (2) carriers detect that trait in others, (3) carriers preferentially help those with the trait.
Provide a real‐world example of genetic recognition.
Social amoebae or colonial ascidians fuse with genetically similar individuals and reject dissimilar ones, promoting cooperation among like genotypes.
What is intra‐genomic conflict?
Conflict among different genetic elements within one individual when they have divergent evolutionary interests.
How do X and Y chromosomes illustrate intra‐genomic conflict?
X‐linked alleles may favor female fitness, while Y‐linked genes benefit males, creating tension over trait expression and resource allocation.
How can mitochondrial DNA vs. nuclear DNA cause conflict? Summarize an experiment.
mtDNA is maternally inherited and can harbor mutations that benefit females but harm males; experiments in mice and fruit flies show certain mtDNA variants reduce male fitness without female effects.
What is genomic imprinting and its role in conflict?
Genes expressed differently depending on parental origin, balancing or mediating conflicts between maternal and paternal genetic interests.
Why are intra‐genomic conflicts important for the geometric view of relatedness?
They add complexity to genetic‐distribution models by introducing local tensions even when overall relatedness is high.
What core question does the “Significance of Fitness Maximisation” address?
Whether inclusive fitness is truly maximized by organisms—or if it’s simply a useful theoretical measure implying they behave as if maximizing future genetic representation.
What empirical evidence supports inclusive fitness maximisation?
Alarm calls in squirrels and cooperative breeding in birds show patterns largely predictable by inclusive fitness models.
How is inclusive fitness maximisation analogous to principles in other disciplines?
It parallels the principle of least action in physics or profit maximisation in economics, fitting observed evolutionary outcomes.
What does the “contextual complexity” argument say against perfect fitness maximisation?
Ecological and developmental constraints, plus unpredictable trade-offs (e.g., disease, environmental change), can prevent organisms from achieving a true fitness optimum.
How do intragenomic conflicts challenge global fitness maximisation?
Different genetic elements within an individual may have divergent interests, producing local fitness maxima for some genes rather than a single global optimum.
What is the haplodiploid hypothesis in the evolution of eusociality?
In haplodiploid insects (bees, ants), females are diploid and males haploid, so sisters share on average 75% of their genes, which was proposed to favor worker altruism.
Why can average sister relatedness fall below 0.75 in real insect colonies?
Because queens may mate with multiple males or colonies may have multiple queens, lowering the mean relatedness among workers.
Besides high relatedness, what other factors contribute to eusociality?
Ecological conditions, developmental constraints, parental manipulation, nest-building behaviors, and lifetime monogamy.
What is the modern consensus on the “3/4 effect”?
High sister relatedness can facilitate eusociality but does not alone cause it; it’s one part of a broader set of genetic, ecological, and behavioral factors.
