Question

Read the following statement and justify the same in your own words with the help of suitable examples.
Geographical and reproductive isolation of organisms gradually leads to speciation.

Accepted Answer

A species is a group of organisms that can reproduce among themselves and produce fertile offsprings. Due to the geographical barrier, separation of some individuals of one species occurs. This separation prevents reproduction among the separated groups leading to reproductive isolation. The separated group will follow its own evolutionary course and evolve into a different species. Moreover, geographic isolation is known to contribute to divergent evolution, resulting in unique phenotypes.

An example of speciation is the Galápagos finch. Different species of these birds live on different islands in the Galápagos archipelago, located in the Pacific Ocean off South America. The finches are isolated from one another by the ocean. Over millions of years, each species of finch developed a unique beak that is especially adapted to the kinds of food it eats. Some finches have large, blunt beaks that can crack the hard shells of nuts and seeds. Other finches have long, thin beaks that can probe into cactus flowers without the bird being poked by the cactus spines. Still other finches have medium-size beaks that can catch and grasp insects. Because they are isolated, the birds don’t breed with one another and have therefore developed into unique species with unique characteristics.

Maharashtra Board Solutions for Chapter: Heredity and Evolution, Exercise 8: Exercise

Maharashtra Board Science Solutions for Exercise - Maharashtra Board Solutions for Chapter: Heredity and Evolution, Exercise 8: Exercise

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