Sympatric Speciation скачать в хорошем качестве

Sympatric Speciation

   • Speciation      • Mode of Speciation/Types of Speciation      • Allopatric Speciation      • Parapatric and Peripatric Speciation   Sympatric speciation is speciation that occurs when two groups of the same species live in the same geographic location, but they evolve differently until they can no longer interbreed and are considered different species. Sympatric speciation can be seen in many different types of organisms including bacteria, cichlid fish, and the apple maggot fly, but it can be difficult to tell when sympatric speciation is occurring or has occurred in nature. An extremely recent example of sympatric speciation may be occurring in the apple maggot fly, Rhagoletis pomonella. Apple maggot flies used to lay their eggs only on the fruit of hawthorn trees, but less than 200 years ago, some apple maggot flies began to lay their eggs on apples instead. Now there are two groups of apple maggot flies: one that lays eggs on hawthorns and one that lays eggs on apples. Males look for mates on the same type of fruit that they grew on, and females lay their eggs on the same type of fruit that they grew up on. Therefore, flies that grew up on hawthorns will raise offspring on hawthorns, and flies that grew up on apples will raise offspring on apples. There are already genetic differences between the two groups, and over a long period of time, they could become separate species. This shows how speciation can occur even when different subgroups of the same species have the same geographic range.