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Originally Posted by Michaelangelica
This is not good "Survival of the Fittest" How does Darwin explain Death, extinction?
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Death is the mechanism by which natural selection works on the individual. Extinction if the mechanism by which natural selection works on the species, or higher taxonomic group.
I sense this is a major stumbling block for you, but I am not quite sure why. It should be the keystone of the concept, yet you are seeing it as a negative. Look at it like this:
Fitness = Life
Unfitness = Death
On a second point, evolution is not seen today as being purely the result of natural selection. Genetic drift and factors such as gene flow, or genetic recombination of various sorts, are also clearly understood to play an important role. These aspects are fundamental to the modern synthesis of Darwinism.
In addition, other factors are slowly being recognised as playing a role. Recent research has demonstrated that speciation through hybridisation is much more common than originally thought. The potential for environmental factors to effect the expression of genes in offspring has been recognised. Thus, epigenetics, while not constituting a wholesale return to Lamarckian ideas definitely puts a new twist on the role of the environment.
