Creation vs. Evolution
Neo-Darwinism
As you would expect with a field of scientific inquiry, much has
been discovered since the time of Darwin. In particular, current
knowledge of genetics has been applied to evolution. Consequently,
the theory of evolution has been modified and augmented. These new
changes are referred to as Neo-Darwinism. An even newer term that
supercedes Neo-Darwinism has been coined by Futuyma to cover the
current ideas on evolution -- Modern Synthesis. Following
is a description of Modern Synthesis.
- The major tenets of the evolutionary synthesis, then, were that
populations contain genetic variation that arises by random (i.e.
not adaptively directed) mutation and recombination; that
populations evolve by changes in gene frequency brought about by
random genetic drift, gene flow, and especially natural selection;
that most adaptive genetic variants have individually slight
phenotypic effects so that phenotypic changes are gradual (although
some alleles with discrete effects may be advantageous, as in
certain color polymorphisms); that diversification comes about by
speculation, which normally entails the gradual evolution of
reproductive isolation among populations; and that these processes,
continued for sufficiently long, give rise to changes of such great
magnitude as to warrant the designation of higher taxonomic levels
(genera, families, and so forth)."
- Futuyma, D.J. in Evolutionary Biology, Sinauer Associates, 1986;
p.12
For a fuller explanation of Modern Synthesis and Neo-Darwinism,
see the article, The
Modern Synthesis of Genetics and Evolution by Laurence
Moran. His main points are summarized here.
There are three important differences between Modern Synthesis
and Darwinism.
- Several mechanisms of evolution are recognized in addition to
natural selection, including random genetic drift.
- Characteristics are inherited as discrete entities called
genes. Variation within a population is due to the presence of
multiple alleles of a gene.
- Speculation is (usually) due to the gradual accumulation of
small genetic changes. This is equivalent to saying that
macroevolution is simply a lot of microevolution.
Another good reference to check on this subject is
Polymorphism and the History of Evolutionary
Theory.
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