Evidence for Evolution

[GaryK]

Darwin is dead and not coming back!

That video isn't an an example of any actual science. It is just a bunch of old guys pontificating and philosophizing. I any event, What do you actually think Behe is saying here?

He invents this ill-defined concept of irreducible complexity but doesn't actually define what he means by parts or whole. Logically one would start with individual atoms which is what biochemists such as himself would start with. But he starts with molecules in some examples and whole structures in other examples. And many of the complex processes he talks about as being irreducibly complex have simpler analogs in more primitive protist and bacterial cells.

Creationists such as Behe used to point to the human eye as their keystone example of an irreducibly complex organ. That was one of Behe's key examples of irreducible complexity. But in recent years scientists have documented a myriad of examples of more primitive vertebrate eyes, both in living organisms and the fossil record. In fact, today the eye is now one of the anatomical structures about which we have the most complete understanding of its gradual evolution. So you don't hear Behe talking about the human eye anymore. Instead he has retreated to more obscure examples such as the bacterial flagellum or protein transport

The whole notion of irreducible complexity misunderstands how organs (or cell organelles) work, and how evolution works. It is true that the human eye or some cell organelle won't work if you remove one single part. But evolution doesn't work by adding fully formed parts to a pre-existing structure in the same way that say mechanical engineering works. Where an engineer might swap out one part for another. Rather, the entire structure evolves as a unit: Organelles, cells, and the whole organism.

In any event, all of the major claims in his 1996 book "Darwin's Black Box" have since been refuted and disproven by various scientists. And it turns out that Behe himself lied about his book undergoing peer review when it turns out that it did not. His own department at Lehigh University has repudiated his work as unscientific.

Look, I get that I'm not going to convince you of anything here (and vice versa). But pseudoscientists like Behe who lie and distort facts do not make a compelling argument for or against anything.

Like I said, actual scientists make their names and go down in history by overturning existing theories and proposing new and better ones. When someone uses science to actually overturn the theory of evolution by natural selection and propose some different and more powerful theory that explains the change that we observe in the natural world all around us. Then they will become world famous and be listed among the greats like Newton, Einstein, Pasteur, and yes, Darwin. It would frankly be one of the most exciting scientific developments of the century. I would be immensely intrigued and excited so see that sort of new scientific breakthrough.

This video clip of a few old guys pontificating amongst themselves is not that.

I didn't watch the video but the one "old guy" is John Lennox and he has debated people like Richard Dawkins and Christopher Hitchens and, IMO, came out of those debates with very convincing arguments. He may be old but he ain't just any "old guy".

[Falco Knotwise]

What proof is there - from the study of genetics - that natural selection can select a variation that is not already potentially within the genetic coding of the species?

I’m talking about the theory that an organism cannot vary indefinitely because there are only a finite number of possible variations to choose from, so that effectively it would be impossible to create a new species from within that gene pool. In other words, an organism can’t mutate its way out of its own species.

My question is whether there is physical evidence from the study of gene structures or is it currently only the theory of natural selection itself that explains why “speciation” is possibile/probable?

I’m genuinely asking because, as you can see, I don’t consider myself an expert here.

This really isn’t something I’ve spent a whole lot of time on in the past.

[Ken]

What proof is there - from the study of genetics - that natural selection can select a variation that is not already potentially within the genetic coding of the species?

I’m talking about the theory that an organism cannot vary indefinitely because there are only a finite number of possible variations to choose from, so that effectively it would be impossible to create a new species from within that gene pool. In other words, an organism can’t mutate its way out of its own species.

My question is whether there is physical evidence from the study of gene structures or is it currently only the theory of natural selection itself that explains why “speciation” is possibile/probable?

I’m genuinely asking because, as you can see, I don’t consider myself an expert here.

This really isn’t something I’ve spent a whole lot of time on in the past.

I'm not an expert in genetics either. I teach it at the HS level in both regular and AP bio classes but that is just briefly scratching the surface of the subject. However since all living organisms on the planet have the same DNA, just in different combinations and chromosomes, one could theoretically take the DNA of any organism and edit/rewrite it enough to produce any other organism. Just like you could take the same exact 26 letters and assorted punctuation marks found in any book in the English language and with enough editing and re-writing turn it into any other book in the English language. You could take the letters in the Bible and rearrange them to form James Joyce Ulysses or the Lord of the Rings or any other work in the English language. So yes, organisms can, in fact, vary infinitely

Generally speaking mutations are frequent and relatively constant. By far the species we have studied most closely is humans because the whole field of medicine is hugely concerned with genetic diseases caused by mutations. In humans mutation rates have been estimated to be on the order of 10−4 to 10−6 per gene per generation. The rate of nucleotide substitutions which is the most common form of mutation is estimated to be 1 in 108 per generation, implying that 30 nucleotide mutations would be expected in each human gamete. That is out of about 100,000 genes in the human body of which only about 25,000 actually seem to be protein-coding genes that serve a function. There are more complex types of mutations that affect large sections of DNA or whole chromosomes but they are less common.

Put another way, each sperm and egg that forms has on average about 30 mutations from the parent cells. The vast majority do nothing at all since about 75% of the human genome doesn't seem to code to any specific instructions. Another portion have no effect because they don't change any instructions. There are only 4 nucleotides in DNA that are read in 3 letter combinations to produce coding instructions for amino acids and there are many 3-letter combinations for each amino acid. So for example you can have a mutation that changes the codon GCA to GCG or GCC or GCT and it still codes to the same instruction. Most mutations that actually do something are benign. They don't really have any obvious positive or negative effect. Some are highly detrimental and we call those genetic diseases. And a few provide some sort of trait that might provide some advantage in a given habitat.

So speaking about organisms generally now and not humans, there are a vast number of traits that might be advantageous in some way. Maybe it is a color change, maybe the animal is slightly bigger or smaller, maybe it has thicker fur or thinner fur, maybe a bigger fat layer which might help in cold climates or a thinner fat later which might help in warm climates. The list is endless. And they are all dependent on the specific habitat and niche that the organism occupies. But if those changes confer any sort of reproductive advantage which usually means that the individual is more likely to survive to reproductive age and reproduce then we would expect nature to select for that gene mutation (natural selection). And negative mutations that cause an animal to be disadvantaged in survival and reproduction would be expected to be weeded out over time. Which is also a form of natural selection.

That is why evolution doesn't work on traits that operate past reproductive age. So, for example, some genetic mutation that makes an organism more resistant to cancer and dying in old age? There is no evolutionary mechanism to select for it since that trait doesn't present itself until AFTER the organism is done reproducing. That is why we don't see any evolutionary pressure to create longer and longer lived organisms. By the time such traits present themselves the individual has long since stopped reproducing.

[Ken]

I didn't watch the video but the one "old guy" is John Lennox and he has debated people like Richard Dawkins and Christopher Hitchens and, IMO, came out of those debates with very convincing arguments. He may be old but he ain't just any "old guy".

Well, I watched the video and he doesn't say much. It is mostly just a clip of Michael Behe talking about one or two examples of the idea he invented which he calls "irreducible complexity" Which he suggests as an argument against a nearly 200-year-old comment made by Charles Darwin.

You all do realize that Michael Behe is an evolutionist. He completely accepts the science about the age of the earth and all the natural processes such as mutations and natural selection that compose the theory of evolution by natural selection. We should be clear about that. He accepts all of evolutionary science.

All he really does is find a few examples of structures (human eye, bacterial flagella, certain protein transports) that he "claims" are irreducibly complex and then posits that those examples are signs that there is some designer (God) that is stepping in to manipulate evolution from time to time to make it work better. That is his notion of intelligent design. So he isn't making any sort of argument in favor of a Biblical narrative of creation at all. Not even in the slightest. Rather, he's making an argument in favor of some vaguely defined concept of "intelligent design". Which is frankly very unscientific because you could assert that any aspect at all of the natural world from atomic structure to DNA is the result of intelligent design. That gets into questions of faith which are not science.

Nevertheless, as science advances, even his examples are getting chipped away one by one. The vertebrate eye, for example, was one of his favorite examples 30 years ago. Now he no longer mentions it because science has since uncovered a great deal of information about the evolution of the vertebrate eye from simpler to more complex forms. So his examples are becoming more obscure.

The thing about science is that it is exceedingly easy to find things that we don't know or understand. Even today in 2023 we have only studied a tiny fraction of the diversity of life on earth let alone all the processes and components of very form of life. Take bacteria, for example. There are an estimated 10^30 bacteria on the planet which is 1 followed by 30 zeros. And there are an estimated to be between 10^7 and 10^9 different species of bacteria on the planet which is between 10 million and 1 billion species. We don't even have an estimate that is precise within 2 orders of magnitude. That means you can walk out to your backyard, scoop up a spoon of soil, and find about 1 billion bacterial cells and about 10,000 different species of bacteria, many if not most of which have never been studied or described by science. Much less to the detail of exploring the evolutionary origins of a specific trait like flagella.

What we don't know about the natural world vastly exceeds what we do know. And every time we find something new (such as sequencing the entire human genome) it only opens up thousands of new questions and avenues for investigation and we find out how much more we DON'T know.

This means it is ridiculously easy for people like Behe to pick some random thing in nature and make a claim about it (irreducible complexity) and get away with it for a while since it is probably something that no one has ever actually studied. But if and when other scientists actually take a hard look at the thing in question they find he is wrong. He is just some guy at a small university in PA that is focused mainly on undergraduate education not graduate research. The scientific world doesn't devote itself to examining or debunking his claims. Although his own university's biology department has disavowed them as unfounded pseudoscience.

In fact, the world of life sciences doesn't really spend that much time on evolution. For example, if you look at the biology department at the University of Washington where I attended and my daughter currently attends you will find that what they call "evolution and systematics" is only one specialty out of 20 that they do work and research in. And it is far from the largest field of study since most research dollars are in other areas of live sciences such as virology, molecular biology, ecology, botany, etc. https://www.biology.washington.edu/people/faculty Without doing a complete census I would expect that no more than about 1 in 50 biology faculty at UW are working in the field of evolution. The cutting edge interest is mostly elsewhere. So the world of science is really not focused on examining the claims of people like Behe or Lennox. They are free to do their own peer-reviewed research, publish it, and then people will pay some attention if it is anything new and interesting. But they mostly don't do that at all. They go on talk shows and philosophize instead of doing actual science.

[ohio jones]

However since all living organisms on the planet have the same DNA, just in different combinations and chromosomes, one could theoretically take the DNA of any organism and edit/rewrite it enough to produce any other organism. Just like you could take the same exact 26 letters and assorted punctuation marks found in any book in the English language and with enough editing and re-writing turn it into any other book in the English language. You could take the letters in the Bible and rearrange them to form James Joyce Ulysses or the Lord of the Rings or any other work in the English language.

Interesting. I've generally seen the Infinite Monkey Theorem used against evolution, rather than in support of it.

[Ken]

However since all living organisms on the planet have the same DNA, just in different combinations and chromosomes, one could theoretically take the DNA of any organism and edit/rewrite it enough to produce any other organism. Just like you could take the same exact 26 letters and assorted punctuation marks found in any book in the English language and with enough editing and re-writing turn it into any other book in the English language. You could take the letters in the Bible and rearrange them to form James Joyce Ulysses or the Lord of the Rings or any other work in the English language.

Interesting. I've generally seen the Infinite Monkey Theorem used against evolution, rather than in support of it.

Evolution isn't random any more than selective breeding by humans to produce 500 different varieties of apples is random. If evolution was random then it would, indeed, go nowhere. Mutations can be random, but then out of the millions of mutations that occur with a species population every generation, only those few that confer some higher level of reproductive fitness are selected for by the evolutionary process of natural selection. So it is very much the opposite of random.

The point I was making is that there is no theoretical outward limit to any species' genome. In theory, with enough gene editing or mutations you could turn any species into any other species, or into some new species that we have yet to see. Genetics is just an alphabet that can be used to duplicate any existing species or any new species that you care to imagine. There are physical limits in the natural world. For example, you probably couldn't put wings on a blue whale and expect it to fly. Far too much mass. Or you couldn't scale up an insect to the size of an elephant and expect its exoskeleton to function. At least on our earth. Maybe on some other planet with far less gravity it would be possible. Who knows.

I'm just responding to Falco Knotwise's question about whether there is only a set amount of possible variation within the genetic code of any given species. That is not the case. There is near infinite possible variation. Perhaps there is some numerical limit out there after you have combined and recombined every possible combinations of genes in every way possible. But that number is so astronomically high as to be effectively infinite.

[Falco Knotwise]

I'm just responding to Falco Knotwise's question about whether there is only a set amount of possible variation within the genetic code of any given species. That is not the case. There is near infinite possible variation. Perhaps there is some numerical limit out there after you have combined and recombined every possible combinations of genes in every way possible. But that number is so astronomically high as to be effectively infinite.

Thanks Ken. Like I said I’ve not given this a whole lot of thought before, so I guess I’ve still got some pretty primitive ideas in my head.

Okay, so I confess I’m actually quite okay with the ToE, which doesn’t mean I don’t think there’s *plenty* room for criticism. Darwin was a good biologist but a terrible metaphysician and social Darwinism has had some pretty devastating effects that I think continues in various forms. (Probably most of us would agree with that.)

The Catholic Church today supports “theistic evolution” and rejects a literal interpretation of Genesis - creationism. (The fact is, most of the Church Fathers did as well.)

I’m quite satisfied with that position.

https://en.wikipedia.org/wiki/Evolution ... lic_Church

How do you feel about Henri Bergson? Ever heard of him?

[Soloist]

The Catholic Church today supports “theistic evolution” and rejects a literal interpretation of Genesis - creationism. (The fact is, most of the Church Fathers did as well.)

Can you support the church father’s claims?
Perhaps as a follow on question, who are you calling church fathers?

[Falco Knotwise]

The Catholic Church today supports “theistic evolution” and rejects a literal interpretation of Genesis - creationism. (The fact is, most of the Church Fathers did as well.)

Can you support the church father’s claims?
Perhaps as a follow on question, who are you calling church fathers?

Augustine argued long ago that since the first and second day occurred before the sun and moon were created that it was probably symbolic. He speculated (I think) that the first light of creation was intelligence, if I remember correctly.

There were others upon whose works Augustine was drawing. If I can find something on it, I’ll post it. I think there was something from Villanova University.

[Soloist]

Augustine argued long ago that since the first and second day occurred before the sun and moon were created that it was probably symbolic. He interpreted the first light (I think) as intelligence, if I remember correctly.

There were others upon whose works Augustine was drawing. If I can find something on it, I’ll post it. I think there was something from Villanova University.

I can see Augustine speculating on that. I personally have no trouble believing it as wrote. Elsewhere we get told that

Rev 21:23  And the city had no need of the sun, neither of the moon, to shine in it: for the glory of God did lighten it, and the Lamb is the light thereof

So perhaps God created the light.
If you assume that it was symbolism, then I think Ken’s position ends up a logical assumption.