1. “The activity of N2RB gene declines in older mice and causes a decline in learning ability.” Some have suggested that this is beneficial because it means older mice cannot forage as efficiently as they once did, which frees up resources for the next generation. This hypothesis is based on group selection because:
a. It deals with two populations, older and younger mice, rather than one species as a whole.
b. The trait of interest is said to have features that reduce the reproductive success of some individuals.
c. The trait of interest is said to cause individuals to sacrifice some reproductive opportunities in order to help another generation of mice to grow and reproduce.
2. “If a mutation were to occur in which the N2RB gene doubled, so that individuals carried two copies of the gene instead of one, these individuals would be guaranteed to live longer and reproduce more because they could learn better into the later part of life.”
a. This statement is probably false because it considers only the benefits of the extra copy of the gene, not the fitness costs.
b. This statement is probably false because these individuals would interfere with turnover in the population, a necessity for evolution by natural selection.
c. This statement is surely true because better learners would remember where to find food better, and so could survive better.
d. This statement is probably true because the gene product of N2RB has an effect on the functioning of brain cells.
I have very little BIO background. Asking for HELP!
THANKS
Quick Reply
