MurkyWaters writes:
It clearly states that the origin of life is part of evolutionary biology which makes it part of the science of evolution which means it is part of evolutionary theory.
The theory of evolution does not include the origin of life, just as home building does not include the origin of lumber. Home building assumes lumber and doesn't concern itself with where the lumber came from, just as evolution assumes life and doesn't concern itself with where life came from.
Your source appears to prefer to view the field of evolutionary biology as including both the theory of evolution and abiogenesis (theories of life's origins). It is not trying to assert that abiogenesis is part of the theory of evolution.
However it is not a coincidence that all of these concepts are discussed in every verbose reference on evolution. That is because they are all part of evolutionary theory. Evolution theorizes that life arose from non life billions of years ago.
Actually, no. That would be abiogenesis.
This
statement from Wikipedia's Life on Earth article characterizes the relationship between abiogenesis and evolution pretty clearly:
The chemical evolution from self-catalytic chemical reactions to life (see Origin of life) is not a part of biological evolution, but it is unclear at which point such increasingly complex sets of reactions became what we would consider, today, to be living organisms.
Moving on:
Evolution theorizes that all the diversity of life we see today arose from a common ancestor which means one kind changed into another kind.
Well, sort of. Replace "kind" with "species" and this is fine. "Kind" has no formal definition within biology, nor within creationism, apparently.
It is absolutely and equivocally NOT a fact that the earliest life we know existed 3.5 billion years ago (maybe the fact that this date has changed a dozen times might be a clue). It is a theoretical conclusion based on a presuppositional interpretation of known facts. A different interpretation of these same known facts (evidence) would place the creation of life around 6000 years ago.
Well, it really isn't accurate to say that these same known facts are open to radically different interpretations. Concluding that life began 6000 years ago actually requires ignoring broad swaths of evidence, not reinterpreting it.
At one point in an earlier message you said this:
Kinds (UMich) - “The second definition emphasizes the appearance of new, physically distinct life forms that can be grouped with similar appearing life forms in a taxonomic hierarchy. It commonly is referred to as macroevolution”, as opposed to species - “members of a species are individuals that look similar to one another”.
This definition of species is the morphological species concept. It is only applied to species that don't reproduce sexually or which are known only from fossils. In most other circumstances the biological species concept is applied.
The UMich site appears to misrepresent how inadequate the morphological species concept is for classifying many species. It describes morphological species concept as if some scientists would actually consider applying it to living sexually reproducing species. I suppose if there were some rare never-captured species for which we only had a picture or a skeleton then the morphological species concept would be the only option, but when classifying living populations then the biological species concept applies.
I guess I should add that the morphological species concept is often applied in cases where a newly identified species differs significantly morphologically from any existing species. Many new insect species are identified this way every year.
The morphological species concept is usually deprecated because it can so easily lead to errors. Species which are identical morphologically may still be different in other ways, such as the behavioral differences in some species of wasps. And some species go through dramatic morphological change during their life cycle and so could be identified as two species when they are actually one, such as the larval and adult stages of many insects.
A true theory can be tested. However, you can’t seem to get it through your head that conjecture about past events is NOT testable. We can interpret facts based on our presuppositions, but we were not there in the past and cannot recreate past events for testing purposes.
This is just the old familiar creationist assertion that past events cannot be reconstructed from available evidence, which is, of course, clearly wrong. Forensics, archeology, cosmology, geology, they all depend upon reconstructions based upon available evidence.
It’s not strange at all that I have not provided a definition of kind because it’s essentially irrelevant, just as a definition of species is.
In the vast majority of cases, species identification is clear and unambiguous. For sexually reproducing species the definition of species as a population of interbreeding organisms usually works fine. But the world is a complicated place, and ambiguous situations always arise. For example, say you have population A in one place, and population B in another. Population A and B can interbreed with one another, so we call them the same species. But then we find another population C in yet another location, and while C can breed with B, it cannot breed with A. In other words, A and B can interbreed and so are a single species, and B and C can interbreed and so are a single species, but A, B and C taken together are not a single species, because A cannot interbreed with C.
This is just a simple example of how difficult a complicated world can make the definition of simple concepts like species, but the mere fact that complex scenarios exist which defy simple classification does not mean that our definition of species is useless or meaningless, not even close. In most cases the simple biological species concept is more than adequate.
First, species is an arbitrary man-made classification...
Man-made, yes, but arbitrary, no. When you have a rule like "population of mutually interbreeding organisms", that is the opposite of arbitrary.
...which may soon go through dramatic revision based on genetics research so when a species has evolved is a completely arbitrary and therefore non-useful determination for evolution.
I'm not sure why you say this. There's nothing coming out of genetics research to indicate that the concept of species needs to change. Genetic studies can be very helpful for determining degree of relatedness.
Interestingly, a genetic view of life tells us that all species are transitional, except those that end up going extinct.
As I read on through your list of definitions of the theory of evolution, it is apparent that you're responding to RAZD's discussion of the mechanisms of evolution (which very briefly is just descent with modification by means of natural selection acting upon inherent variation) with rather broad definitions of the theory of evolution.
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.
By the way, notice that only one of your definitions of the theory of evolution even mentioned the origin of life, and then only as the starting point for evolution.
You certainly have a twisted sense of what a theory is. I can propose a theory that the moon was made of cheese a million years ago. That doesn’t do much for the science of cheese making but it is nonetheless a theory.
A scientific theory bears no resemblance to what you're doing here. First, hypotheses are constructed to explain observed phenomena, then research is conducted to test the hypothesis, then a theory is constructed around the resulting body of evidence to explain and interpret it, and if the research is replicated and validated then the theory becomes accepted. The idea that the moon was once made of cheese is not an attempt to explain some body of evidence, and it has not been replicated and validated, and so it is not a scientific theory.
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.
--Percy