The third chimpanzee
This is the first book by Jared Diamond. It paved the way for more to come. His style is unique because the book is an amalgamation of information from various disciplines e.g. evolutionary biology, genetics, geography, linguistics etc. He is a true polymath.
There are two species of chimpanzee i.e. the common chimp and the bonobo or pygmy chimpanzee. Scientists from a different planet would have easily classified humans as the third chimpanzee because the genetic make up of the three are almost identical. No matter how small the difference is, that what makes human uniquely human.
On unusual (compared to other animals) sex lives i.e. concealed ovulation and copulation
Evolutionary biology offers three possible explanations
to reduce aggression and increase cooperation among males;
to strengthen the bonds between particular couples, laying the foundations of the human family;
to encourage men to bond permanently with their partners, which intern makes men more confident that they are the fathers of the children their partners bear.
A man and woman who want their child and their genes to survive must cooperate with each other for a long time to rear that child. At the same time, they must cooperate economically with other couples living close by. Regular sexual relations between the man and woman create a bond that is closer than the couples ties to their friends and neighbours. These close bonds between couples are a kind of social cement, not just a mechanism of fertilisation. Our sex life takes place in private to emphasise the difference between sexual and nonsexual partners within the same close group.
On an evolutionary biological explanation of the show off.
Life purpose, according to evolutionary biology, is to perpetuate one’s genetic materials. Competing for mates is natural. In the animal kingdom, fights for mates are nature way of selecting the best (based on strength) genetic material to perpetuate. People, on the other hand, have different way to compete. People who woo possible mates with expensive gifts and other displays of wealth are saying, in effect, “I have plenty of money to support a family, you can believe my boast, because you can see how much money I'm spending now without care.” People who show off jewels or sports cars gain status, because everyone knows that those objects are expensive therefore difficult to obtain. It’s the same economic principle of ‘signalling’. The show off signals economic strength to get a mate.
On significance of geography
Disasters have been caused by politicians ignorant of geography. In the 19th century, the Europeans powers that colonised Africa divided up the continent into territories. Later, when the territories became independent nations, they inherited the borders which often had no relation to the geography (perfect straight line drawn on a map), ethnic relationships, or economies of the African people. This lead to continuous territorial disputes, never-ending wars between neighbours and persistent economic disadvantages of the people.
On our problems and our future
We are the only ones creating our problems, so it's completely within our power to solve them. We are the only animals that can learn from the experiences of other members of our species living in distant places or in the past. Among the hopeful signs are many realistic ways to avoid disaster, such as by limiting human population growth, preserve natural habitats, and adopting others environmental safeguards.