![]() There were few, perhaps no, places in tropical or Southern Africa that could have provided such a combination. To evolve adaptations to dry, open country, the erects would have had to suffer a period of isolation from other hominins, in an appropriately discrete habitat. Because the adaptation of equatorial species inhibits their colonization of temperate regions, the successful emigration of the erects out of Africa strongly suggests that this was a northern, not a tropical species. The australopiths never made it beyond the southern margins of the Sahara. So what ecological niche forged the modern human body? Anatomical innovations are selected when they enable more efficient exploitation of some particular niche. Natural selection explains why bodies change. Most of these changes were introduced with Homo Erectus: I have previously explained why we are bipedal (flexible waist, straight backs, walking on two feet).īut why do we have scent glands in our armpits? Fat in our asses? Such weird hair? Hairless skin with massive subcutaneous fat deposits? But why do we look so different from our closest living relative, the chimpanzee? The moderns ( H sapiens) emerge out of Africa, and completely conquer the globe.The archaics ( H heidelbergensis) appear, who eventually give rise to the Neanderthals, Denisovans, and us.The erects ( H erectus) with near-modern anatomies.They presumably used these anatomical and cultural gifts to compete with other scavengers on the savannah (projectiles to repulse competitors, stone flakes to speedily butcher a carcass). They began making stone tools (Mode 1 tools, the Oldowan industry). Their hands show adaptations for flexibility, and their shoulders and elbows for throwing missiles. These creatures had the same small bodies, but larger brains. In contrast, the habilines (e.g., Homo Habilis) took a different strategy: meat eating. These impressive creatures comprise a blend of human and cow-like features. The paranthropes adapted by promoting tubers from backup to primary food. The descendents of Australopithecus had to adapt their diet. Desertification would have reduced the wetlands where australopiths found fruits, seeds, and underwater roots. Africa began drying out about 3 million years ago, making the woodlands a harsher and less productive place to live. Dental morphology and microwear together suggest that australopiths acquired food from a new source: tubers (the underground storage organs of plants).Ĭlimate change is responsible for the demise of the australopiths. They could walk comfortably, but retained their adaptations for tree living as well. The very first unique hominin feature to evolve was bipedality, which was an adaptation for squat-feeding. The most recent common ancestor of humans and chimpanzees lived 7 mya (million years ago). Content Summary : 2100 words, 21 min read
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