Behavioral Ecology

Contents

Problems

Problem :

What is the difference between direct fitness and inclusive fitness, and how are they calculated?

Direct fitness is the number of offspring an individual produces. Inclusive fitness is the direct fitness plus indirect fitness. Indirect fitness is calculated by the number of related individuals produced multiplied by the degree of relatedness to those individuals.

Problem :

What is the degree of relatedness you have to your father's first cousin's child?

Figure %: Degree of relatedness to your father's first cousin's child.

From you to your father is r=.5. From your father to his father is r=.5. From your grandfather to his sister (or brother) is r=.5. From your great aunt to her son is r=.5. And from your father's first cousin to his child is r=.5. Therefore your degree of relatedness is .5^5=.03125.

Problem :

Your grandmother was dating three men when she became pregnant with your mother. One of the three men who might be your grandfather has another grandchild. What is your degree of relatedness to his grandchild?

Figure %: Degree of relatedness to a possible cousin

The degree of relatedness through your grandfather is r=.5^4, but there is only a 1/3 probability that this man is your grandfather, so r=(1/3)(.5^4)=.0208.

Problem :

In a haplodiploid honeybee colony, the Queen mates with three drones. The paternity of all members of the colony is unknown. Are you more likely to help your brothers or your sisters?

Figure %: Relatedness is a haploidiploid bee colony with unknown paternity.