The Natural History Reader in Evolution

The Natural History Reader in Evolution

The Natural History Reader in Evolution

The Natural History Reader in Evolution

Excerpt

"Nothing in biology makes sense except in the light of evolution." So wrote the late geneticist Theodosius Dobzhansky, perhaps the central figure in the development of the "synthetic theory" of evolution, still the dominant set of ideas on how the evolutionary process actually works. In its broadest sense, biological evolution means that all organisms are descended from a common, primitive ancestor. All life is unified by virtue of its common origin. Life has achieved its present state of diversity as lineages of organisms have branched and become modified during the course of the last 3.5 billion years.

It was Dobzhansky who, in his book Genetics and the Origin of Species ( 1937), achieved the first comprehensive integration of the relatively young science of inheritance--genetics--with the original Darwinian vision of adaptation and natural selection. Critical to this venture was Dobzhansky's early training as a field naturalist, specializing in ladybird beetles. Darwin knew that organisms resemble their parents, and that there is heritable variation within populations. Both are necessary for natural selection to work, retaining favorable variations to maintain or improve the adaptations of organisms. In hammering out the essentials of an understanding of the principles of heredity, early geneticists began to question some of the older Darwinian notions. Thus mutations seemed often to be large in scale, and harmful in their effects--leading some geneticists to suppose that natural selection, working on a groundmass of smoothly intergradational variation, was not the real stuff of evolution. Large-scale mutations (if not lethal) were sufficient to lead to the instantaneous creation of new species--or so early saltational ("jumping") genetical theories of evolution saw the matter. But, by the thirties, geneticists had come to realize that many mutations are relatively slight in magnitude, and either neutral or downright beneficial in their effects--paving the way for a return to orthodox Darwinism, but this time with a firm basis in genetic principles. Dobzhansky went one step further, melding experimental results in the laboratory with observations of organisms in the wild.

Thus we have a theory of evolution that sprang in large measure from . . .

Search by... Author
Show... All Results Primary Sources Peer-reviewed

Oops!

An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.