Beyond The Selfish Gene

We need to reconsider our theories of evolution.

Darwin’s theory of evolution depends on reproduction (the capacity of individuals to survive and produce offspring), on heredity (the tendency of offspring to resemble their parents), and on variation (individuals differing from one another). Darwin recognized that natural selection occurs because the differences among individuals affect their survival and the numbers of offspring they produce. If the variations that affect reproduction are heritable, they increase in frequency and the outcome is evolutionary change. Many generations of natural selection in a particular direction, for example for moving efficiently through the air, increase the frequency of variants that eventually can give rise to complicated structures like wings and coordinated processes like flying.

Clearly, to flesh out Darwinian evolution, we need to understand the processes that are at its core. We need to know how organisms develop to survive and reproduce, what is inherited and how it is inherited, how heritable variations are generated, and what is selected.

Since the mid-20th century, biological heredity has been identified with genes*, which are usually equated with DNA base sequences that have functional effects. Reproduction has been seen in terms of the replication of DNA, and variation in terms of random (non-specific and functionally blind) changes in DNA base sequences. Because the origin of heritable variations was assumed to be independent of development and the selective environment, the generation of variations was seen as unimportant when trying to understand the adaptive fit between organisms and their environments. Natural selection alone could explain adaptation.

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