Development of Brain
Comparison of Brain Development human and animal brains shows steady progression in brain size in relation to body weight. Not only the size but also there is expansion of areas as cerebral cortex. Frontal lobes are involved in inhibition of instinctive behavior associated with intelligence which is suppression of instinctive behavior. Temporal lobes which lie behind the temples on each side of brain cover storage and retrieval. The parietal lobes which lie on top contain cerebral cortex which specialize in linking up and synthesis of ideas and information–another important aspect of intelligence.

The advanced hominids include the Neanderthal man and Cro–magnon man. Most important as far as independence is concerned the one specialization which man did acquire is bipedalism. Ramapithecus was a hominid close to our ancestors who lived 10–12 million years ago. Finally the 1st true man Homo–erectus evolved about 800,000 years ago showing further increase in brain size, tool use and cultural adaptation.

The social animal
When the present condition of man is compared with lower forms of life from which he originated, it is obvious that an evolutionary ladder is ascended, leading from the earliest protoplasm to amphibian, to reptiles, on to mammals, the primates, then man; which is the ladder of social evolution.

Sexual Behavior
The second main social link is that which is created between male and female for purpose of procreation. This is sexual behavior. Sexual behavior has been important in primate evolution. Development is particularly evident on sight or visual signals. Like most mammals the females of all primates except humans have an oestrous cycle. This is a regular and usually non–seasonal cycle of sexual receptivity at the height of which a female ovulates and shows sign of increased sexual excitability. In humans the menstrual cycle predominates due to unresponsiveness to changes in hormone levels. Sexual adaptations also include more curvatures in the body outline, pubic hair and development of prominent breasts and also secondary sexual characteristics such as standing upright, meeting face to face and kissing. The human male’s penis in erect state is larger than any primate and may have evolved as a means of signaling male’s sexual excitability. Apart from these, maternal behavior seen in context of mother–child relationship is developed.

The final truth
Whatever the final truth about man’s social origins, there is no doubt that such behavioral adaptations have led to the development of structural societies and advanced material culture have been dependant upon mental and physical adaptations which have given man the highly developed body and mind he possesses today.

Speculations
What remains to be seen is how far is evolution going to extend? Is there a limit to human evolution along with advance in intelligence? Can man reach all frontiers in nature? Can he supercede nature? Most important question in our minds which still remains unsolved is, whether Intelligent life exists out in the universe? Is there another earth in the formation or already formed? Let us cross our fingers and hope for a miraculous union of intelligence that this universe has in store for us.