Question

which of the following is not an example of allopatric speciation? group of answer choices in a population of minnows, some individuals have red bellies and some have white bellies. minnows begin to preferentially mate with others of the same color, eventually leading to divergence between the two color morphs. two populations of shrimp became physically separated by the isthmus of panama approximately 3 million years ago. when placed together in an aquarium, they are not able to interbreed. due to erosion at its headwaters in the mountain of new zealand, a river which used to drain into a river basin in the east of the south island now drains into a river basin in the west. the galaxiid fish living in those headwaters become isolated from downstream populations in the east. these river-basin changes result in different selection pressures acting on the newly-separated populations, which adapt to different sets of ecological conditions. in the hawaiian islands, a typhoon blows several individuals from a population of spiders over to the next island. they survive the rough journey, and spider populations on the two islands begin to accumulate differences due to genetic drift.

Answer 1

The scenario with minnows preferring to mate with others of the same color is not an example of allopatric speciation, as it lacks geographical isolation.

The other scenarios provided describe allopatric speciation, where geographic separation leads to reproductive isolation and the emergence of new species.

Therefore, the correct answer is: option "minnows preferring to mate with others of the same color".

Step-by-step explanation:

Allopatric speciation is a process in which new species are formed through geographic isolation.

The following are not examples of allopatric speciation: in a population of minnows, some individuals have red bellies and some have white bellies. Minnows begin to preferentially mate with others of the same color, eventually leading to divergence between the two color morphs.

The other scenarios given describe examples of allopatric speciation. For instance, when two populations of shrimp become physically separated by the isthmus of Panama approximately 3 million years ago, and are no longer able to interbreed when placed back together, this is indicative of allopatric speciation due to geographic separation.

Another example is the galaxiid fish in New Zealand, which become isolated due to a river changing its drainage pattern. The resulting separation exposes them to different selection pressures, leading to potential allopatric speciation.

Lastly, spider populations blown to a separate island by a typhoon and then evolving differently due to genetic drift is also an example. These scenarios represent the impact of geographic barriers leading to reproductive isolation and evolutionary divergence.