Final answer:
Allopatric speciation occurs when populations become isolated by a geographic barrier, leading to reproductive isolation and the formation of new species. Examples of allopatric speciation include the separation of bird populations and the drying up of a connecting creek between two ponds.
Step-by-step explanation:
Allopatric speciation occurs when populations become isolated by a geographic barrier, leading to reproductive isolation and the formation of new species. In the given examples, the correct choices that describe allopatric speciation are:
- c. Pygmy nuthatch and brown-headed nuthatch are separated by hundreds of miles in which neither bird occurs
- d. A creek connecting two ponds dries up permanently, separating those aquatic populations in those two ponds until they eventually speciate
In option a, the Cichlid fishes of Lake Tanganyika undergo sympatric speciation, not allopatric speciation. In option b, the marine invertebrates reproduce in the same location, so they do not experience geographic isolation that leads to allopatric speciation.