Question

please discuss the role of changing climate in our divergence from the chimpanzee line. Emphasize our ancestral diet and dentition. (150 wds).

Answer 1

Environmental condition alterations has stimulated important changes in human orgin .Variations in temperature, annual cycles of precipitation, and larger swings in climate adaptations of plants and animals and ultimately may determine their survival. Changes in global and regional climates apparently had profound effects on the evolutionary history of many species .Chimpanzee (Human last common ancestor ) and human original divergence is considered to be occured 13 million years ago , and hybridization until 4 million years ago.

The common ancestral lineage of the three extant genera, chimpanzees, gorillas and humans,remained in Africa. Main climatic change that lead to dispersal of them believed to happend in Africa and Eurasia. Over past 8million years climate from monsoonal forcing , ice volume changes in high altitude , changes in solar radiation , volcanism , coastlines , greenhouse gas effects and Tibetan and East African ocean gate way changes. It created possibility of divergence and development of behavioural and intellectual characters.

Dentition :The structure of a tooth and even the amount of enamel, for example, hint at what the teeth are adapted to eat. 2:1:2:3 dental formula Ancestors like chimpanzee posses diastema and humans do not. Incisors and canines are expression of aggression and defensive weapon. Premolar and molar are flat. Diet :Major dietary shifts in human evolution, including meat eating, cooking, and those associated with plant and animal domestication. examples: Chimpanzee bonobos - frugivorous diet , hunt small primates and non primates occasionally. Ar.ramidus - mixed fruits or tough vegetations Australopithecine - large and thick enameled teeth for eating starch rich underground foods bulb, corns etc