Divergent evolution is the process of two or more related species becoming more and more dissimilar, while convergent evolution is unrelated species becoming more similar in appearance as they adapt to the same environment. The two types of evolution are important in generating variation and ensuring that species play their role.
Divergent evolution involves accumulation of differences between groups leading to formation of new species, usually due to diffusion of the same species to various and isolated environments. The gene flow among the distinct populations is blocked by the environment, leading to differentiated fixation of characteristics through genetic drift and natural selection.
An example of divergent evolution is adaptive radiation. The red fox and the kit fox are two species that have undergone divergent evolution. The red fox lives in mixed farmlands and forests, where its red color enables it to adapt with surrounding trees. The kit fox lives on the plains and in the deserts, where sandy color conceals it from prey and predators. The kit fox also has large ears that help it adapt in the desert environment. Dinosaurs are other examples of divergent evolution.
An example of convergent evolution is the resemblance of the cactus, which grows in the American desert, to the euphorbia, which grows in the African deserts. Both plants have fleshy stems with spines. These adaptations enable the plants to store water and ward off predators. Other examples of convergent evolution include: emus, rheas and ostriches.