Even though your question is not directed to me, I would like to respond to it.
First let me clarify. Variation is a general term which says that reproduction reshuffles the deck every time a life form is conceived. Now we know that half of the genes comes from the male and half from the female, but which ones and how they are mixed are random. Children are not like their parents and children of the same parents are not like each other. Each one is different or maybe in some cases each spawn is different, but variation is built into the sexual reproduction.
Now there is another kind of variation usually called mutation. Mutation is variation caused by changes in the DNA outside the normal. This can be mistakes in the way the DNA is copied, radiation. etc. This is usually believed to be the source of exceptional change in evolution. There are other sources of change also, such as reusing old DNA stored in the genome or borrowing from other species.
The point I am trying to make is that variation is an integral part of life and cannot be stopped. It is random because it indeterminate, but it has a definite purpose which is to allow life forms to adapt to their environments.
I hope this answers your question and I am sure Eddie will given his opinion if needed.
My question is a hypothetical and you did not answer it. It is an attempt to get people to think about mechanisms.
“Variation is a general term which says that reproduction reshuffles the deck every time a life form is conceived.”
No, that is not what “variation” means. You are conflating the source of variation with the quantifiable phenomenon of variation. People and animals in populations vary in heritable ways.
“Children are not like their parents and children of the same parents are not like each other. Each one is different or maybe in some cases each spawn is different, but variation is built into the sexual reproduction.”
This is correct, but my question to Eddie or anyone else has nothing to do with the source of heritable variation. It’s about whether most evolution is acting upon existing or new variation.
My more general point with Eddie is that one can easily discuss these things without reference to people or to books.
Evolution would go on for quite some time even without any new mutations. (Benkirk’s question made it clear that he meant no new mutations.) There is plenty of variation in existing populations of organisms. (Except, of course, in Oompa-loompas.)
[quote=“Eddie, post:5, topic:4327”]
And about a year or so ago, Joao claimed explicitly that evolution would proceed almost as fast with no new mutations at all, just on the strength of existing variation, and was challenged on that claim by biologist/biochemist Preston Garrison. Preston asked for, not the names of people or books, but evidence for the claim. Joao dropped out of the conversation at that point, and has never returned since with the “data” which support the claim.
[/quote]A link just might possibly be useful. So would discussion of issues instead of people and what they say, which appears to be impossible for you to achieve.
[quote=“Eddie, post:11, topic:4327”]
I cannot remember what thread it was posted on. I have read thousands of columns here, over several years. I am no better at using the search engines than you are. You can find it as quickly as I can, possibly even more quickly. I am unwilling to invest the time.[/quote]
I did and cannot find it.
Yet despite your relentless bragging about how much you’ve read, you clearly understand very little of evolutionary biology.
Perhaps you are mistaken. As for you not stating the truth, were you stating the truth in the other thread in which you wrote that you were breaking off discussion with me?
Why would you make such an accusation and refuse to support it? Doesn’t that make you a man lacking intellectual integrity by the standard by which you want to judge others?
I haven’t found any evidence to support your claim. Unlike you, I’ve looked.
[quote]Do you uphold that thesis? Then provide the evidence. Who first articulated it (Joao) doesn’t matter at all, according to you. Tell me about the artiodactyl and the whale. I’m all ears.
[/quote]How about answering my questions first? Why are you so resistant to separating evolutionary mechanisms to understand them better?
As a mental experiment, it is easy to imagine a gene pool of some living thing (let’s suppose CLAMS!), where there are 10 different kinds of shell color … and there has been for 1 million years … and for all those millions of years, the dominant clam color has swung back and forth, in response to sea bottom changes… without a single new color appearing in the gene pool.
As a DIFFERENT mental experiement, perhaps we could call it the OPPOSITE experiment, imagine a lagoon where an isolated species of crocodile has lived for 1 million years. It looks just like it did 1 million years ago. But for whatever reason, the genetic system in this species throws off a huge number of variations every generation… but the variations deal with biochemistry and physiology - - none of which produces any observable surviving changes in the appearance of the crocodiles.
For starters, if you had 10% of the understanding of evolutionary theory you pretend you have, you’d clearly know that you would have to stipulate the size of the initial population and the polymorphism of the population.
Secondly, real scientists are doing real, empirical work on the subject, unlike your buddies at UD and DI, who just talk.
Physicochemical Evolution and Molecular Adaptation of the Cetacean Osmoregulation-related Gene UT-A2 and Implications for Functional Studies
Scientific Reports 5, Article number: 8795 (2015)
Comparative genomics reveals conservation of filaggrin and loss of caspase-14 in dolphins
Experimental Dermatology, 2015, 24, 365–369