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Evolution - Baldwin and The Genetic Code

Smoothing the landscape

The Hills-and-Valleys model does suggest that 'sudden sharp peaks' are harder for evolution to find than 'peaks on gently rising surfaces'. In turn this means that a biological mechanism that smooths out the peaks makes it easier to find the maxima.
  • Baldwin Effects - Smooths the peaks by plasticity in the organism.
  • The Genetic code - Is designed so that point errors are less likely to lead to radical changes in properties.

Index3.1 Smoothing

Baldwin Effects

The Baldwin Effect mentioned earlier can be seen as one which smooths the evolutionary landscape, and indeed this is how Dennett in his book "Consciousness Explained" presents it.

Dennett's interest in the Baldwin Effect is that it suggests the advantage the brain's flexible strategies give. Dennett doesn't emphasise it, but the flexible response of our immune system is also subject to the Baldwin Effect. The Baldwin Effect promotes evolution of the immune system.

In both cases there is in addition a transfer of non-genome information. With the brain we learn some strategies by verbal transmission of ideas. With immune response, maternal milk contains antibodies which help to 'educate' the immune system.

In both cases a flexible system promotes evolution and in both cases there is a non germ-line transfer of information.

Index3.1 Smoothing

Genetic Code

Are there other ways in which the evolutionary landscape is smoothed? Yes.

The genetic code by which DNA is translated into protein is organised in such a way that point mutations (changes of a single DNA base) tend to preserve the character of amino acids used in a protein. The evolutionary landscape would be bumpier if point mutation typically led to a very different amino acid being used.

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"Evolution - Baldwin and The Genetic Code" page last updated 5-July-2003