Chapter 3 Summary and Analysis

There is no telling how many living things exist on earth, Dawkins claims. Of insects alone there may be a million million million. But even though plants and animals and viruses are all very different, they are basically made of the same molecule—DNA. The author says this points to the idea that all living things have come from the same sort of replicators which have found different ways to preserve their pattern or genes. There is no way to know if earth's DNA is different than the original replicators because no record of them exists.

DNA is a long series of tiny molecules called nucleotides, just like proteins are chains of amino acids. The DNA is made of two nucleotide chains, whether it's in a mouse, a bacteria, a human, or a tree. The reason the mouse, bacteria, and...