Question

What is meant by the statement "Evolution may proceed along 'genetic lines of least resistance'"?

(a)- Evolution operates on the set of phenotypes that a genotype can produce under all possible environmental conditions.
(b)- The phenotypes produced by genes under selection will be those that require the least energy input, despite potential fitness gains.
(c)- Characters with little genetic variation will constrain the rate of natural selection; correlated characters may increase in fitness less rapidly, because they can evolve only along the greatest axis of variation. Because mutations may be more likely to appear at some locations in a gene than at others, we can easily predict the phenotype it will experience when natural selection occurs.
(d)- Functionally correlated characters will not remain genetically correlated, because they are broken up during segregation and crossing over.

Answer 1

C. Characters with little genetic variation will constrain the rate of natural selection

Step-by-step explanation:

Natural selection can have an effect only as long as there are variations on characters on which it can select upon. Genetic variation is independent of the environment or the needs that a species may have to become better adapted to its changing environment. In other words, genetic mutations are the raw material on which natural selection can work. If there is a low rate for mutations to occur, then natural selection will proceed at a slow pace. The opposite is also true. Since mutation rate may be more frequent at some locations in a gene than at others, it can be predicted that the characters coded in that gene location will be more likely to be affected by natural selection and therefore what phenotype may be molded by natural selection.