Question

Question 4: Try to trace the various components of human evolution (hint: brain size and function, skeletal structure, dietary preference, etc.)

Class 12 - Biology - Evolution Page 142

Answer 1

The various components of human evolution are as follows.
(i) Brain capacity
(ii) Posture
(iii.) Food / dietary preference and other important features

i.About 15 million years ago, primates calledDryopithecusandRamapithecusexisted. They were hairy and walked like gorillas and chimpanzees.Ramapithecuswas more man-like, whileDryopithecuswas more ape-like. So, these were the forerunners of hominids.

ii.Progress was made further when a skull was discovered about 5 million years ago. It had a brain size of about 500 cm3within the range of an ape’s brain, but its jaw and teeth were human like. It was probably not taller than 4 feet but walked upright. It was named asAustralopithecus africanusand lived in the East Africa grasslands. Evidence showed that this species hunted with stone weapons but essentially ate fruits.

iii.FromAustralopithecusevolvedHomo habiliswho was characterised by having a larger brain thanAustralopithecus(650-800 cc), used tools and were bipedal. They probably did not eat meat.

iv.Homo erectusappeared about 1.5 million years ago. Their brain capacity increased to about 800-1,200 cc, and they migrated to Asia and Europe. Fossils of ‘Java man’ and ‘Peking man’ belong toHomo erectus. They probably ate meat.

v.Homo erectuswas later replaced byHomo sapiens. There were several sub-species ofH. sapiens, a widespread one of which wasH. sapiens neanderthalis, a large brained game hunter. They have a brain size of 1,400 cc and lived in the Near East and Central Asia between 100,000 and 40,000 years ago. They used hides to protect their body and buried their dead ones.

vi.The oldest remains ofH. sapiens sapiensappeared about 35,000 years ago, probably having evolved from Neanderthal man. They were as large brained (1,500 cc) as they were today and existed as hunter gatherers in co-operative bands. They were stout, short and used hides for clothing. They built huts and buried their dead ones.

vii.Prehistoric cave art developed about 1,800 years ago. Agriculture came about 10,000 years ago and human settlements started.

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