L2: Counter intuitive behaviour

Question 1

What is the idea of group selection?

Answer 1

Certain characteristics of individuals are adaptive not at the individual, but at the group level, to help the group survive and reproduce, and so individuals sacrifice their own personal fitness

Question 2

Why is the theory that group selection acts on self restraint to control population size?

Answer 2

Groups that don’t overexploit their resources don’t prosper, would go extinct.

Question 3

Why can’t group selection work in principle?

Answer 3

The dynamics of groups in actuality are not suitable - between group dynamics is not strong enough for selection to act to favour restraint genes

Question 4

What is infanticide?

Answer 4

When a new male takes over a group, he will often kill the young offspring

Question 5

What is concluded about the hypotheses that infanticide in hanuman langurs is actually non adaptive?

Answer 5

Infanticide may not be adaptive, so isn’t under natural selection, instead it is the males way of reducing overcrowding. Is unlikely because infanticide is no more prevalent in large groups

Question 6

What is concluded about the hypotheses that infanticide in hanuman langurs is favoured by natural selection at the individual level?

Answer 6

Infanticide frees females to become pregnant sooner, the male can father offspring sooner, and so increases his fitness, before he is thrown over by another male - this is the most likely hypothesis

Question 7

What is concluded about the hypotheses that infanticide in hanuman langurs is favoured by natural selection at the group level?

Answer 7

Infanticide has evolved to avoid overcrowding, which would cause the group to over exploit its resources. However, this is unlikely, because individual selection is much stronger.