Question

Altruistic behaviours between closely related animals are selected for because they

• A. Reduce fighting between species
• B. Ensure survival of the altruistic individual
• C. Force individuals to cooperate with one another and so increase population growth
• D. Increase the frequency of the altruistic individuals genes in the next generation

Answer 1

Answer: (B)

Ensure survival of the altruistic individual

An organism is said to behave altruistically when its behaviour benefits other organisms, at a cost to itself. The costs and benefits are measured in terms of reproductive fitness, or expected number of offspring. So by behaving altruistically, an organism reduces the number of offspring it is likely to produce itself, but boosts the number that other organisms are likely to produce.

So the correct option is 'ensure survival of the altruistic individual'.