Friday, April 4, 2014
How Human Beings Colonized the Five Continents?
In 1871, Charles Darwin in his book ‘The Descent of Man’ suggested that humans have evolved from the same African ape ancestors that gave rise to the gorilla and the chimpanzee. Although little fossil evidence existed at that time to support Darwin’s case, numerous fossil discoveries made since then strongly support his hypothesis. The first humans or how the human race evolved is a matter of some interesting phases.
The earliest primate with two distinct qualities – grasping the fingers and binocular vision, evolved around 65 million years ago giving rise first to prosimians and then to monkeys. Other mammals do have binocular vision but the combination of the above two provided the ground for an ease in adaptation with the environment.
The earliest primates split into two further categories around 40 million year – prosimians (before monkeys) and anthropoids. The prosimians were nocturnal generally feeding on fruits and plants. The anthropoids, or higher primates, include monkeys, apes, and humans. Anthropoids are almost all diurnal—that is, active during the day—feeding mainly on fruits and leaves. Evolution favoured many changes in eye design, including colour vision, that were adaptations to daytime foraging. An expanded brain governs the improved senses, with the braincase forming a larger portion of the head. Anthropoids, like the relatively few diurnal prosimians, live in groups with complex social interactions.