Members of two different species possess a similar looking structure that they u
ID: 8004 • Letter: M
Question
Members of two different species possess a similar looking structure that they use in a similar fashion to
perform the same function. Which information would best help distinguish between an explanation based on
homology versus one based on convergent evolution?
A) The two species live at great distance from each other.
B) The two species share many proteins in common, and the nucleotide sequences that code for these
proteins are almost identical.
C) The sizes of the structures in adult members of both species are similar in size.
D) Both species are well adapted to their particular environments.
E) Both species reproduce sexually.
Answer is B. Im trying to understand the theme here. AND what is B saying??
homology: same ancestor different adaptions VS Convergent evolution: different ancestor, same adaptions (similar environment) is my thinking right?
Explanation / Answer
Homology is where two or more species share the same basic structure, but it produces different functions. Homology is evidence that the basic structure was inherited from a common ancestor, and then re-purposed for different functions.
Convergent evolution is where two or more species have basically the same function with very different basic structures. Two very different structures that achieve a similar function is evidence that the two species came from very different ancestors that converged on the same function; hence convergent evolution.
The answer, B, is part of the definition of convergent evolution. The ultimate cause of convergence is usually a similar evolutionary biome, as similar environments will select for similar traits in any species occupying the same ecological niche, even if those species are only distantly related.