05 Origin and Evolution of life - part 14 -Evolution of life

05 Origin and Evolution of life - part 14 -Evolution of life - 


Human Evolution

  • It has been traced that the human evolution appeared to have evolved from a tree dwelling shrew like animal. This process began in Palaeocene epoch.
  • During this period, dwindling forests forced arboreal mammals to adapt to life on land. This descent must have been the driving force. 
  • In the following chart, it can be seen that we are most closely related to gibbons, chimpanzees and gorillas.
  • The major evolutionary trends in transition from ape to man are considered further. 
  • Special characteristics have been acquired by man in the course of evolution. 
  • Major changes that took place in evolution of man include -  
  1. increase in size and complexity of brain and enhanced intelligence
  2. increase in cranial capacity
  3. bipedal locomotion
  4. opposable thumb
  5. erect posture
  6. shortening of forelimbs and lengthening of hind limbs
  7. development of chin
  8. broadening of pelvic girdle
  9. development of lumbar curvature
  10. social and cultural development (articulated speech, art, development of tools, etc).
    Cranial capacity of human begins increased over a period of time and large size of frontal lobehelped in development of high forehead. 
  • Increase in intelligence necessitated physical development so that body and brain could be used effectively and productively. 
  • Freedom of forelimbs from locomotory function and opposable thumb led to better utilization of hands for holding objects effectively and development of motor skills etc. 
  • Bipedal locomotion, upright posture coupled with stereoscopic vision helped man to move around safely on land. 
  • Evolutionary history of man was traced with thehelp of fossil remains found over a period of time.
  • Some of our ancestors and their evolutionary history is shown in the table. 
  • The above table clearly shows the gradual increase in cranial capacity, shape of skull and dentition of the ancestral humans till date. Our journey of evolution still continues..... 

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