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Stephen Jay Gould

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We do not inhabit a perfected world where natural selection ruthlessly scrutinizes all organic structures and then molds them for optimal utility. Organisms inherit a body form and a style of embryonic development; these impose constraints upon future change and adaptation. In many cases, evolutionary pathways reflect inherited patterns more than current environmental demands. These inheritances constrain, but they also provide opportunity. A potentially minor genetic change […] entails a host of complex, nonadaptive consequences. […] What “play” would evolution have if each structure were built for a restricted purpose and could be used for nothing else? How could humans learn to write if our brain had not evolved for hunting, social cohesion, or whatever, and could not transcend the adaptive boundaries of its original purpose?
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"Hyena Myths and Realities", p. 156

 
Stephen Jay Gould

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Sociobiology is not just any statement that biology, genetics, and evolutionary theory have something to do with human behavior. Sociobiology is a specific theory about the nature of genetic and evolutionary input into human behavior. It rests upon the view that natural selection is a virtually omnipotent architect, constructing organisms part by part as best solutions to problems of life in local environments. It fragments organisms into “traits,” explains their existence as a set of best solutions, and argues that each trait is a product of natural selection operating “for” the form or behavior in question. Applied to humans, it must view specific behaviors (not just general potentials) as adaptations built by natural selection and rooted in genetic determinants, for natural selection is a theory of genetic change. Thus, we are presented with unproved and unprovable speculations about the adaptive and genetic basis of specific human behaviors: why some (or all) people are aggressive, xenophobic, religious, acquisitive, or homosexual.

 
Stephen Jay Gould
 

Independent derivation meshed beautifully with the triumph, from the 1930's on, of a strict version of Darwinism based on the near ubiquity of adaptive design built by natural selection... Arthropods and vertebrates do share several features of functional design. But those similarities only reflect the power of natural selection to craft optimal structures independently in a world of limited biomechanical solutions to common functional problems - an evolutionary phenomenon called convergence.

 
Stephen Jay Gould
 

A complete theory of evolution must acknowledge a balance between “external” forces of environment imposing selection for local adaptation and “internal” forces representing constraints of inheritance and development. Vavilov placed too much emphasis on internal constraints and downgraded the power of selection. But Western Darwinians have erred equally in practically ignoring (while acknowledging in theory) the limits placed on selection by structure and development—what Vavilov and the older biologists would have called “laws of form.”

 
Stephen Jay Gould
 

Steve is extremely bright, inventive. He thoroughly understands paleontology; he thoroughly understands evolutionary biology. He has performed an enormous service in getting people to think about punctuated equilibrium, because you see the process of stasis/sudden change, which is a puzzle. It's the cessation of change for long periods of time. Since you always have mutations, why don't things continue changing? You either have to say that the particular form is highly adapted, optimal, and exists in a stable environment, or you have to be very puzzled. Steve has been enormously important in that sense. Talking with Steve, or listening to him give a talk, is a bit like playing tennis with someone who's better than you are. It makes you play a better game than you can play. For years, Steve has wanted to find, in effect, what accounts for the order in biology, without having to appeal to selection to explain everything—that is, to the evolutionary "just-so stories." You can come up with some cockamamie account about why anything you look at was formed in evolution because it was useful for something. There is no way of checking such things. We're natural allies, because I'm trying to find sources of that natural order without appealing to selection, and yet we all know that selection is important.

 
Stephen Jay Gould
 

Many similarities of basic design among animal phyla, once so confidently attributed to convergence, and viewed as testimony to the power of natural selection to craft exquisite adaptation, demand the opposite interpretation that Mayr labeled as inconceivable: the similar features are homologies, or products of the same genes, inherited from a common ancestor and never altered enough by subsequent evolution to erase their comparable structure and function. The similarities record the constraining power of conserved history, not the architectural skills of natural selection independently pursuing an optimal design in separate lineages. Vertebrates are, in a certain sense, true brothers (or homologs) - not mere analogs - of worms and insects.

 
Stephen Jay Gould
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