cybrsage
Lifer
- Nov 17, 2011
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I am talking about speedy gradualism, which is a form of saltation where they change the time period required for gradual changes from millions of years to tens of thousands of years. Here is a blurb about it:
Speedy Gradualism. Another attempt to resolve the contradiction between neo-Darwinian theory and the fossils is the "speedy-gradualism" argument: If change occurs rapidly during a single time period, but not for millions of years thereafter, the pattern might seem saltational. But what if this "short" period of change lasted 20,000 years? Wouldn't it be reasonable to simply change the meaning of "gradual" and say that while 20,000 years is not a million years, it's still a very long time, plenty of time for gradual selection and everyday genetic phenomena to take their course and create a new type of organism?
This argument was proposed as an explanation of one of the best-documented cases of saltation, the Turkana mollusks described by P. G. Williamson (1981). The speedy gradualists say some shift in the environment forced Williamson's mollusks to change, that the changes occurred "gradually" during a relatively brief (20,000-year) transition period, with the environment stabilizing thereafter, maintaining the new types unchanged for millions of years. But this is not the picture painted in the Origin. There, Darwin explicitly states his views:
natural selection can act only by taking advantage of slight successive variations; she [i.e., Nature] can never take a leap, but must advance by the shortest and slowest steps.3In this kind of evolution, variation arises randomly over time, and is not concentrated in a single, brief interval. But the fact that fossil types appear to come into being abruptly is not the most serious difficulty confronting neo-Darwinism. As Williamson (1981) points out,
The principal problem [with the available paleontological data] is morphological stasis. A theory is only as good as its predictions, and conventional neo-Darwinism, which claims to be a comprehensive explanation of the evolutionary process, has failed to predict the widespread long-term morphological stasis now recognized as one of the most striking aspects of the fossil record.
http://www.macroevolution.net/peripheral-isolates.html
The fossil record and an evolutionary theory without some form of saltation do not match. In other words, evolution without a form of saltation fails to predict the changes we see in the fossil record. As such, it is a failure. With saltation, specifically speedy gradualism, the theory matches the fossil record, so its predictions are valid and the theory is no longer invalid.
That paper explains, then dismisses, the use of speedy gradualism and advocates a completely different theory. They could be right, but for now the evolutionary theory with punctuated equilibrium and speed gradualism (a form of saltation) rules the roost.
The fossil record and an evolutionary theory without some form of saltation do not match. In other words, evolution without a form of saltation fails to predict the changes we see in the fossil record. As such, it is a failure. With saltation, specifically speedy gradualism, the theory matches the fossil record, so its predictions are valid and the theory is no longer invalid.
That paper explains, then dismisses, the use of speedy gradualism and advocates a completely different theory. They could be right, but for now the evolutionary theory with punctuated equilibrium and speed gradualism (a form of saltation) rules the roost.
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