vjsharma25 wrote:
If one of the effects of a genetic mutation makes a
substantial contribution to the survival of the species,
then, and only then, will that mutation be favored in
natural selection. This process is subject to one proviso,
namely that the traits that were not favored, yet were
carried along by a trait that was favored, must not be
so negative as to annul the benefits of having the new,
favored trait.
If the statements above are true, each of the following
could be true EXCEPT:
(A) A species possesses a trait whose effects are all
neutral for the survival of that species.
(B) All the effects of some genetic mutations
contribute substantially to the survival of a
species.
(C) A species possesses a trait that reduces the
species’ survival potential.
(D) A genetic mutation that carries along several
negative traits is favored in natural selection.
(E) A genetic mutation whose effects are all neutral
to a species is favored in natural selection.
Interesting question. Took me just under 2 minutes since it's a could be question, so I had to entertain all possible scenarios.
A: Nowhere does it say that a species cannot possess a trait whose effects are all neutral. The argument deals with mutations being favored in natural selection, not traits per se.
B: Sort of tricky. While a negative trait can be carried along as part of a mutation if it's not detrimental to the species' survival, it is certainly possible that there exists mutations whose effects are entirely positive.
C: Yes, a species can definitely possess a negative trait. However it will not be favored in natural selection as part of a mutation, but the stimulus does not rule out the possibility of a species possessing such a trait.
D: As long as the negative trait is not detrimental, it can be favored during natural selection as part of a mutation.
E: Correct answer. The first sentence explicitly states that one of the effets of a mutation has to contribute substantially to the survival of a species in order for it to be favored in natural selection. Thus, if its effects are all neutral, it cannot be favored.