I want to share an excerpt with you from Chapter 3, subsection 'The alternation of generations'. This offers a unique and poetic explanation for where we come from and how our posterity will receive us:
Our sex is determined by our gametes. All eggs have one X chromosome, while half the sperm have one X and the other half one Y chromosome. A combination of X and X in the fertilized egg will give a female and X plus Y a male. [... T]he germ cells that will ultimately produce the single-celled gamete (an egg or sperm) are set aside very early in embryonic life. If we are born to a middle-aged mother, we may have lived almost as long as an unfertilized egg as we do in the form of a multicellular organism. In reality, each of us leads a double life. There is the romantic life we know, that of a thinking, moving, feeling individual, and there is that secret life lying dormant within us, the sexual life of our gametes - thoughtless, senseless sperm or eggs, waiting for a rare opportunity provided by their host to meet with a gamete of the opposite sex and produce a new individual, thereby handing down the thread of life from one generation to the next. One world is familiar to us, the other alien and mysterious. One is a brief spark of sentient life, the other tied to thousands of millions of years of slow continuous evolution. For the mature sperm, life is nasty, short and brutish. It lives only for a few days and it is a trillion to one chance that it will fertilize an egg. Few will even make it into a woman's vagina. The vast majority are destined to be washed out of the man's reproductive tract each time he urinates, to be flushed down the toilet, ending their days amongst the detritus of civilization in the sewers of some city, or spilled upon the ground, where they die like stranded tadpoles. A woman begins life with millions of eggs, each unique, but virtually all of them die inside her body and, of the tiny fraction that are released, most go unfertilized and are incinerated with menstrual pads. Our gametes are our birthright, but we are unaware of their presence and accord them scant respect.
This alternation of the generations between a mortal soma and immortal germ plasm has fascinated philosophers, theologieans, poets and scientists for generations, and will continue to do so long into the future. For it deals with the very nature of life, and death, and the transmission of our DNA, from generation to generation. At one extreme, there are those who like to think that a chicken is merely an egg's way of making another egg. Or maybe, as Richard Dawkins would have it, the soma is merely the product of an ageless battle between selfish genes, striving for mastery and seeking propagation through succeeding generations. [...] Our life on Earth has not been a series of discontinuous acts of creation, but is an unbroken thread tying us all to our ancestors and with the potential of linking us to innumerable future generations. We are indeed trailing clouds of glory - the glory of billions of years of continuous evolution. We do not create life: we have only the privilege of passing it on.
Genesis, eat your heart out.