Challenges to Neo-Darwinism

[Swammerdami]

In Darwin's model, mutations occur RANDOMLY and are then SELECTED for, based on whether the mutant and his progeny survive.

The researchers here claim that the mutations themselves are NOT random. (But further research is needed to understand and confirm the claim.)

 

[bilby]

this view has always left open fundamental questions, such as the problem of complexity

Whichever journalist wrote that is clearly waaaaay out of their depth, as they obviously have no clue that the sole value of the theory of evolution is that it provides an answer to the problem of complexity.

It's like saying "Gravity is widely accepted in the scientific community, but this has left open fundamental questions such as the problem of why things fall down"

 

[skepticalbip]

In Darwin's model, mutations occur RANDOMLY and are then SELECTED for, based on whether the mutant and his progeny survive.

I would think that the random mutations are more often neutral, only minor variations about the average. Then there are mutations that are detrimental to survival and/or procreation so are generally "selected against"... that many random mutations produce less robust or less sexually appealing results if not serious birth defects. Then there are only a small percentage of mutations that give a survival or reproductive edge so are 'selected for".

 

[Swammerdami]

In Darwin's model, mutations occur RANDOMLY and are then SELECTED for, based on whether the mutant and his progeny survive.

I would think that the random mutations are more often neutral, only minor variations about the average. Then there are mutations that are detrimental to survival and/or procreation so are generally "selected against"... that many random mutations produce less robust or less sexually appealing results if not serious birth defects. Then there are only a small percentage of mutations that give a survival or reproductive edge so are 'selected for".

Yes. I should have written "then possibly SELECTED for" rather than "then SELECTED for."

 

[Peez]

In Darwin's model, mutations occur RANDOMLY and are then SELECTED for, based on whether the mutant and his progeny survive.

The researchers here claim that the mutations themselves are NOT random. (But further research is needed to understand and confirm the claim.)

I notice that earlier you had posted "neo-Darwinism (for our purpose that's just "Darwinism")", but note that Darwin did not mention mutation (or anything like it). That said, I understand what the article reports that the paper claims. I have not yet read the paper, but the article makes a number of false (or at least misleading) statements, so one should be at least cautious.

 

[Swammerdami]

In Darwin's model, mutations occur RANDOMLY and are then [sometimes] SELECTED for, based on whether the mutant and his progeny survive.

The researchers here claim that the mutations themselves are NOT random. (But further research is needed to understand and confirm the claim.)

I notice that earlier you had posted "neo-Darwinism (for our purpose that's just "Darwinism")", but note that Darwin did not mention mutation (or anything like it). That said, I understand what the article reports that the paper claims. I have not yet read the paper, but the article makes a number of false (or at least misleading) statements, so one should be at least cautious.

I am also very skeptical. One reason I posted was to see if this article is refuted. I'd not be surprised if Google would find another scholarly article that laughs at the one in OP.

But what do I know? It was only recently that I learned about RNA editing which, among other uses, helps implement the genetic code. One reason for the nuclear membrane is to keep freshly minted RNA isolated long enough to do the editing, which proceeds MUCH more slowly than the ribosomal translation that occurs once the RNA is outside the nucleus. Intron splicing is also a complicating process.; and human cells can do reverse transcription! (However none of these facilities could explain the paper's claimed results AFAIK.)

Darwin knew nothing about genetics. For him "mutation" was completely vague and the vagueness led to severe inadequacies in his model. However, FWIW he did use the word 'mutation' seven times in Origin of Species. (Eight if you include his single mention of 'transmutation.') Two occurrences of 'mutation' appear in the same sentence:

The belief that species were immutable productions was almost unavoidable as long as the history of the world was thought to be of short duration; and now that we have acquired some idea of the lapse of time, we are too apt to assume, without proof, that the geological record is so perfect that it would have afforded us plain evidence of the mutation of species, if they had undergone mutation.

 

[Peez]

Fair enough, he used the word "mutation" but not with the same definition. My fault: I was being lazy. By "mutation" in this context I meant 'genetic mutation' (changes in the genetic code, rather than changes generally). Darwin was using "mutation" as a synonym for "evolution", he certainly knew virtually nothing about the genetic basis of it. Note that Darwin explicitly did not think that his "mutation" is random.

 

[steve_bank]

Are not evolution and muattion synonymous?

 

[Peez]

"Genetic mutation" and "biological evolution" are not synonymous, but "mutation" can just mean change and "evolution" can just mean change, so they can be synonymous in some cases.

 

[steve_bank]

"Genetic mutation" and "biological evolution" are not synonymous, but "mutation" can just mean change and "evolution" can just mean change, so they can be synonymous in some cases.

'

Semantics.' Mutation' can be metaphor for many things. So can evolved and evolution. The evolution of western democracy. Chrtianity evolved out Judaism.

Genetic mutation to me in general conversation infers biological evolution and vice versa. You can't have one without the other.

On a thread on evolution mutation and evolution are synonmus withgnetc mutation and biological evolution unless used eexplicity in a different context.

This is a 'slam dunk'.

 

[Peez]

Of course it is semantics, how could "Are not evolution and muattion (sic) synonymous?" be anything but semantics?

That said, in the context of biology, as the terms are used by biologists, "mutation" (genetic mutation) is not synonymous with "evolution" (biological evolution). It is possible to have mutation without evolution, and evolution without mutation. Grabbing the nearest general biology text book (it happens to be Campbell Biology, Second Canadian Edition): "mutation" is defined as "A change in the nucleotide sequence of an organism's DNA or in the DNA or RNA of a virus." and for "evolution" there is "Descent with modification: the idea that living species are descendants of ancestral species that were different from the present-day ones, also defined more narrowly as the change in the genetic composition of a population from generation to generation." Not synonyms.

Note that by claiming that under the Darwinian paradigm mutation is random, and that mutation and evolution are synonymous, you are claiming that Darwinian evolution is random.

 

[bilby]

Grabbing the nearest general biology text book (it happens to be Campbell Biology, Second Canadian Edition): "mutation" is defined as "A change in the nucleotide sequence of an organism's DNA or in the DNA or RNA of a virus." and for "evolution" there is "Descent with modification: the idea that living species are descendants of ancestral species that were different from the present-day ones, also defined more narrowly as the change in the genetic composition of a population from generation to generation." Not synonyms.

The meanings Darwin gave to the words was clearly very different though.

He had never heard of nucleotides, DNA, or RNA; And his meaning for "evolution" was a novel idea that he was attempting to explain to an unavoidably ignorant audience.

It's pointless to attempt to understand Darwin using modern definitions for the words he used. We can only grasp his intent if we also understand what his words meant to his contemporary audience, and they would have understood "mutation" to simply mean "change", and "evolution" to mean a progression of changes over time. Neither was a specifically biological word; He was borrowing them from a wider context.

 

[Bomb#20]

Genetic mutation to me in general conversation infers biological evolution and vice versa. You can't have one without the other.

On a thread on evolution mutation and evolution are synonmus withgnetc mutation and biological evolution unless used eexplicity in a different context.

This is a 'slam dunk'.

Mutation is something that happens to an individual organism during meiosis; evolution is something that happens collectively to a population of organisms over many generations. So it's perfectly possible for a group of animals to give birth to generation after generation of mutants and yet never evolve, if by chance all the mutations are deleterious so natural selection preserves the original form of all the genes. Likewise, a population can continue to evolve even without any new mutations, when sex among the preexisting supply of genetic variants creates a hybrid that combines the advantages of both parents with the disadvantages of neither, allowing the hybrid to outreproduce the other animals in the group.

 

[Peez]

Indeed, I did post "he used the word "mutation" but not with the same definition." Our modern concept of evolution is very similar to his, but more detailed since we know far more about it now. Certainly genetic mutation is not something he could address, though it would have been interesting to sit down with he and Mendel.

 

[steve_bank]

That is why it is called Theory Of Evolution not Darwinism. The scope of TOE includes all of the branches of science that feeds into the main theory and its conclusions.

An ancient Greek theorized all life began in the sea. Darwun made a logical deduction bsed on observation. Genetics was yet to come, but the idea of inheritance in plants, humans, and domesticated animals was understood.

 

[Peez]

Indeed people have probably known for thousands of years that individuals tend to share traits with their parents, but the mechanism remained obscure until Mendel made his contribution. It has been a while since I read Darwin, but I seem to remember that his ideas about inheritance were not very good. Certainly Darwin had the opportunity to read Mendel's work, but it is not clear if he did. A interesting discussion at https://academic.oup.com/qjmed/article/102/8/587/1598792#:~:text=A catalogue of Darwin's library from Down House,his scientific library passed to his son Francis.

 

[Swammerdami]

... Certainly Darwin had the opportunity to read Mendel's work, but it is not clear if he did. A interesting discussion at https://academic.oup.com/qjmed/article/102/8/587/1598792#:~:text=A catalogue of Darwin's library from Down House,his scientific library passed to his son Francis.

Very interesting. Loren Eiseley has written a book, Darwin's Century, which tells much about 19th century developments, both by Darwin and by others, of evolution theory. But his book does not mention Focke at all, and implies that Mendel's paper was completely ignored for decades.

One interesting fact in Eiseley's book is that an obscure 1831 book, On Naval Timber and Arboriculture, by Patrick Matthew, has a few sentences which outline the Theory that Darwin published 28 years later. When Matthew complained, Darwin acknowledged that this book, which he hadn't read, laid out the key ideas, albeit in just two paragraphs in an appendix.

As Nature, in all her modifications of life, has a power of increase far beyond what is needed to supply the place of what falls by Time's decay, those individuals who possess not the requisite strength, swiftness, hardihood, or cunning, fall prematurely without reproducing -- either a prey to their natural devourers, or sinking under disease, generally induced by want of nourishment, their place being occupied by the more perfect of their own kind, who are pressing on the means of subsistence.
. . .
Geologists discover ... fossil species [and] an almost complete difference to exist between the species or stamp of life, of one epoch from that of every other. We are therefore led to admit, either of a repeated miraculous creation; or of a power of change, under a change of circumstances, to belong to living organized matter ...

 

[Swammerdami]

This has all been off-topic of course. The thread isn't about Challenges to Darwinism in the 19th century, but about Challenges to Neo-Darwinism in the 21st and late 20th centuries.

Two topics I might discuss are

(a) The huge difference between Eukaryotes and Prokaryotes. One hopes to see, perhaps via fossils, a progression from one form to the next, but Eukaryotes burst into existence leaving no "trail." The gulf between any Prokaryote and any Eukaryote is HUGELY greater than the difference between an amoeba and one cell from a giraffe, or between that giraffe cell and the cell of an apple tree. There are no missing links visible. The chronological ordering of the MANY evolutionary "inventions" which separate Prokaryote from Eukaryote must be guessed or deduced.

(b) According to Nick Lane in his wonderful book Life Ascending: the Ten Great Inventions of Evolution, the evolution of sex is a great mystery. If nobody beats me to it, I might try to summarize that chapter, just to make sure I understand it myself.

 

[steve_bank]

I am not all that knoledgeable so I will bow out.

 

[Peez]

I would argue that these issues have little to do with the thread title, and nothing to do with the subject of the OP. I find it not surprising at all that we do not have a nice clear record of fossils showing intermediates in the evolution of eukaryotic cells from prokaryotic cells (the whole "missing link" thing is a notably creationist tactic). That said, it is true that the sequence in the evolution of early eukaryotes can only be guessed at. The evolution of sex is indeed an interesting topic, about which we know little. Perhaps fresh threads would be appropriate.