Question

A social woodpecker lets its two brothers and four nephews feed on the acorns that it has stored in a communal acorn storage tree. The added food increases the chance that these six relatives will survive over the winter by 50% but it reduces the helpful woodpecker's own reproductive success by the equivalent of 1.5 offspring. Show all your calculations.

1. what was the cost to the social woodpecker in units of inclusive fitness for its altruism?

2. what was the benefit to the social woodpecker in units of inclusive fitness for its altruism?

3. how much inclusive fitness did the social woodpecker gain/lose from its altruism?

4. the behavior was: adaptive/adaptionist/a costly by product of an adaptation/maladaptive? Explain.

Answer 1

Inclusive fitness made up of two component- Direct fitness and Indirect fitness.

Direct fitness :- It is paasing own genes via reproduction to next generation.

Indirect fitness:- It is passing genes to next generation by helping relatives.

rB > C

r = coefficent of relatedness (via shared genes)

B= benefit received by recepient(no. of relative individual)

C= Cost to altruist.(no. of offspring)

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4. The behaviour is not adaptive beacuse the woodpecker helped sibing to servive by sharing food. If it left for adaptation their chance of servival will not same. Some may not live in the harsh condition. Here woodpecker increased the chance of servival of individual and insure the gene transfer to next generation.