Bird guides once listed the myrtle warbler and Audubon's warbler as distinct species. Recently, these birds have been classified as eastern and western forms of a single species, the yellow-rumped warbler. Which of the following pieces of evidence, if TRUE, would be cause for this reclassification?
A) The two forms interbreed often in nature, and their offspring have good survival and reproduction.
B) The two forms live in similar habitats.
C) The two forms have many genes in common.
D) The two forms have similar food requirements.
E) The two forms are very similar in coloration.

Question

Quizplus · Accepted Answer

If the two forms interbreed and produce viable offspring, this provides evidence that they are the same species. This is because different species cannot produce fertile offspring. Therefore, if the myrtle warbler and Audubon's warbler interbreed and produce healthy offspring, it would indicate that they are the same species and should be reclassified as such.

Bird Guides Once Listed the Myrtle Warbler and Audubon's Warbler