This is in response to the information\assertions made in
Message 118 regarding the Galapagos Finches and whether this constitutes evolution or not:
MurkyWaters writes:
... In all of the change that we have observed, fruit flies are still fruit flies, moths are still moths, finches are still finches. No evolution. It doesn’t matter if we simply observe species changing. ...
As we see from the
Definition of Evolution you can define evolution several ways, but the required elements are (a) hereditary traits and (b) natural selection operating on those traits as expressed in the individual phenotypes, and that result in (c) the change in hereditary traits within populations of species over time (or from generation to generation). When these conditions are met evolution has occurred. This is "descent with modification" to use Darwin's formulation, and thus we would always expect that the offspring of (X) would always be (X) regardless of what (X) is, and to say otherwise is to misunderstand or misrepresent evolution. If there is a change in hereditary traits from one generation to the next then evolution has occurred, whether it is still the same species or not.
If you want to discuss the definition of evolution go to
Definition of Evolution
MurkyWaters writes:
... As we all know, the word “evolution” can refer to this theory or it can refer to the “process” (or mechanism) that is occurring today (as many references pointed out). In other words, you can look to the Galapagos finches and say “this is evolution” referring to the process (CISOT), or you can say the Galapagos finches does not go far enough to demonstrate evolution, referring to the theory (MTM) ...
{Where "CISOT" refers to "change in species over time" (where the "change" has been specified as hereditary) and "MTM" refers to "molecules to man" (which MurkyWaters also states as "all the living forms in the world have arisen over billions of years from a single common ancestor which itself came from an inorganic form").
This is essentially agreeing that evolution has occurred by the process of mutation and selection. As we see from
The Definition for the Theory of Evolution that there is a lot of confusion as to what constitutes a theory, and we also see that we can define the theory of evolution several ways, but the essential elements are (a) evolution per a scientific definition (such as "change in hereditary traits from one generation to the next"), and (b) the theoretical postulation that this applies to any level of change that has been observed, whether that change be microevolution within a population or macroevolution and the increasing divergence possible between related species with the increasing passage of time.
MurkyWaters writes:
(Percy, Message 115)
The Galapagos finches are an example of evolution in action because scientists were able to observe modification through successive generations brought about by changes in the natural environment that in turn changed which variations were more desirable than others.
This is where we part ways. This is exactly the point that initiated this entire debate. It all depends on how you define “evolution”. It may demonstrate “evolution” which some have deceptively defined as only change in species over time but it DOES NOT demonstrate the theory of evolution.
The point is not how
people define evolution, but how
evolutionary biologists define evolution. When you use the definition used by the scientists it qualifies as evolution. That there is a conflict with how the
theory of evolution is defined by the "MTM" theory would imply it is a faulty statement of the theory of evolution, not that evolution has not occurred.
Again, if you want to discuss the definition of evolution go to
Definition of Evolution.
MurkyWaters writes:
(Percy, Message 115 ... adding back comments in gray)
You spend much time objecting to "change in species over time," which you abbreviate as CISOT, as part of the theory of evolution. I don't understand why you raise this objection, since all the dictionary definitions you cited include change over time. The entire purpose of Darwin's Origin of Species was to present evidence explaining how the current diversity of life came about by changes in predecessor species.
You’ve made my point. The purpose was to explain how all “the current diversity of life came about”, NOT just how species change. The fact that species change, by itself, DOES NOT rule out the possibility that this diversity is the result of changes to the original created kinds about 6000 years ago.
But applying the theory to the evidence would. When you apply the theory to the evidence back to say the end of the Cretaceous Period (the KT extinction event) or all the way back to bacterial life (when only prokaryotes lived on earth) and show that the change in hereditary traits in populations from generation to generation explains the data sufficiently,
then it validates the theory of evolution over a concept of minimal original "kinds" of animals (especially with certain "typical examples" as listed in Genesis). In fact you only need to go back a few million years before those "typical example" organisms evolved to reach this conclusion.
It is not the
theory that makes the distinction between competing theories, but predictions based on the theory for results when you apply it to the evidence to see if it can explain the evidence: that is what distinguishes one theory from another (and those predictions are usually made to falsify one or the other of competing theories). This is basic to how science works, so once again we need to use definitions as used by scientists that study evolution. This has been reviewed on
The Definition for the Theory of Evolution, and currently the definition of the
theory of evolution as defined on that thread is:
RAZD writes:
Message 158
(1) The modern theory of biological evolution is a synthesis of several validated theories on how species change over time.
(2) The modern theory of biological evolution is a synthesis of several validated theories on how species change over time; it includes theories on how change is enabled, and it includes theories on how changes made within each generation are selected.
(3) The modern theory of biological evolution is a synthesis of several validated theories on how species change over time; it includes theories on how change is enabled, due to the available variations (diversity) within populations from the formation and accumulation of different mutations in hereditary traits, and it includes theories on how changes made within each generation are selected, due to the differential response of organisms under prevailing ecological pressures to their individual development, their ability to pass on hereditary traits to the next generation, and their opportunities to disperse into other ecological habitats.
(4) The modern theory of biological evolution is a synthesis of several validated theories on how species change over time; it includes:
- theories on how change is enabled
...(list of theories on different mechanisms for the formation and accumulation of different mutations in hereditary traits within populations) - theories on how changes made within each generation are selected
...(list of theories on different mechanisms of selection and where and when they operate)
... etc
If you want to discuss the definition of the
theory of evolution go to
The Definition for the Theory of Evolution (which is currently closed but can be reopened on request to moderation staff (see
Thread Reopen Requests 2) or restarted - it's currently at 215 out of a usual 300 messages on a topic, and many of them are discussions not related to the
theory of evolution).
According to that statement of the theory, evolution can be as small a change as just the change in hereditary characteristics from one generation to the next, it does mean that the changes observed in the Galapagos Finches meet the requirements of the theory of evolution as used by evolutionary biology scientists.
What else does MurkyWaters say that impacts this thread on the evolution of the Galapagos Finches? Several times, most recently in
Message 112 and
Message 118 of the same thread, he has made statements like:
MurkyWaters writes:
One of the greatest evolutionary minds, Ernst Mayr, who has been called the “Darwin of modern times” says that change in frequency of alleles is NOT evolution and therefore not a part of the definition.
And let’s not get into this silly notion that evolution is simply a change in frequency of alleles. There are many scientists that disagree with this definition including the Darwin of modern times Ernst Mayr. “Neutral evolution” is NOT evolution.
But of course the change in beak size of the Galapagos Finches is not "
neutral evolution" as it involves selection of hereditary traits from one generation to the next.
As documented on
Message 192 using these quotes of Mayr is misrepresenting what he says, and does not take into consideration where he actually says what evolution
is throughout the book. Some examples are:
quote:
"Evolution is best understood as the genetic turnover of the individuals of every population from generation to generation."
-- Ernst Mayr (2001) What Evolution Is, Basic Books, New York p.76
"Evolution in sexually reproducing organisms consists of genetic changes from generation to generation in populations, from the smallest local deme to the aggregate of interbreeding populations in a biological species."
-- ibid p.157
"In fact, the way organisms are structured, evolution is inevitable. Each organism, even the simplest bacterium, has a genome, consisting of thousands to many millions of base pairs. Observation has established that each base pair is subject to occasional mutation. Different populations have different mutations, and if they are isolated from each other, these populations inevitably become more different from each other from generation to generation. Even this simplest of all possible scenarios represents evolution."
-- ibid p.264
There can be no doubt for anyone understanding what Mayr is saying in this book, that evolution occurs when hereditary traits are selected and that the selection then affects the distribution of those traits in following populations. There can be little rational doubt that applying the statements above to the Galapagos Finches shows that they evolved fully in accordance with the views of Mayr.
Conclusions
(1) evolution as defined by evolutionary biologists involves the change in hereditary traits from generation to generation.
(2) the theory of evolution as defined by evolutionary biologists involves evolution (per 1) and the (testable) postulate that this applies to any observed level of change in species over time.
(3) the change observed in the Galapagos Finches in response to changes in the ecology did involve selection of hereditary traits from one generation to the next, and that this is therefore an example of evolution in action.
(4) the change observed in the Galapagos Finches was explained by the change in hereditary traits from one generation to the next, and this is therefore a validation of the theory of evolution at this (small) scale of change and in this one instance.
Enjoy.
Edited by RAZD, : sp, grammar
Edited by RAZD, : reopening thread link
Edited by RAZD, : reworded section for clarity
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