Chapter 3: History (Genome)

In chapter 3 of Matt Ridley’s “Genome,” he delves into the history of human evolution and how it can be understood through the lens of genetics. He begins by discussing the trend of increasing brain size in animals over time, and how this is related to the development of larger, multicellular bodies during the Cambrian explosion. He notes that there is a trend of increasing complexity in animals over time, and that the brains of the brainiest animals have gotten bigger with each passing age.

Ridley then goes on to discuss the process of calibrating the molecular clock to give an actual date in years for the split between human and chimpanzee ancestors. He notes that this process is difficult, as apes have slow molecular clocks and not all genes agree on the date of the split. The generally accepted range is five to ten million years.

He then compares the human and chimpanzee genomes and notes that the differences between them are small, with only about 2% of the genome being different. He notes that these differences are mostly in genes related to growth and hormonal development, and that the basic biochemistry and body planning genes are largely the same. He also notes that the genetic record is a valuable source of information on our past, as it contains a record of our four-billion-year evolutionary history.

Ridley then goes on to discuss the concept of the “missing link” in human evolution and speculates on what this common ancestor with chimpanzees may have looked like. He notes that scientists are getting closer to understanding this through the study of fossil records, but that the genome will provide a more complete understanding of the pressures of the Pleistocene era on the two species. He concludes by stating that while the behavior of different apes is largely influenced by genetics, the specific mechanisms behind this are not yet understood.

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Related posts:

1. Law 17: Seize the Historical Moment (The Laws of Human Nature)
2. Part 2: Isolate the Victim (The Art of Seduction)
3. Chapter 16: The Capitalist Creed (Sapiens)
4. On Nietzsche’s Thus Spoke Zarathustra Summary (8.4/10)