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The changes in climate, brought about by the cycling process of compression and relaxation of the solid crust, with the associated temperature fluctuations and glaciations, play likely the dominant role in biological evolution.
During the last ice age, many species that could not adapt to the cold climate perished, and new species emerged. Among the plants evolved grasses that were cultivated into the grain-producing varieties, and among the animals, mammoth, bison, and related species evolved into cattle, while wolves were bred into dogs. Among birds, dark colored species, such as crows emerged.
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