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Somewhere I read following paragraphs giving one counter-example to Darwin's theory of evolution.

(By the way, I am a physicist and not a biologist, but I am interested in this field.)

Do these paragraphs point to the reality? What is the current status of "theory of evolution of species" ?

"Darwin cited the giraffe as an outstanding example of natural selection. Supposedly, as a result of extended droughts, the supply of green leaves could be obtained only at the top of the trees, and therefore the shorter necked giraffe died off. The giraffes which grew longer necks survived. However, there is no evidence whatever in the fossil record or elsewhere that giraffes with short necks have ever existed. And what would have happened to young giraffes with relatively short necks?

Darwin failed to realize that body characteristics in offsprings are determined and programmed by DNA factors of the Genes or the Genetic material of the parents, and not by the stretching of the neck or any other bodily exercise."

atom
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    Where is that quotation from? – James Feb 07 '17 at 03:45
  • @James: I got an email from someone whom I do not recognize/know; this is similar to a spam email. – atom Feb 07 '17 at 03:48
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    Ignore it. There is a lot of painfully wrong/uninformed statements in there. Berkeley is a good place to get an overview of the modern understanding of evolution. – James Feb 07 '17 at 04:23
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    As a matter of fact, there is fossil evidence of shorter-necked giraffe ancestors: http://www.livescience.com/52903-transitional-giraffe-fossils.html Also remember that fossilization is a very rare happenstance (otherwise we'd be up to our necks in them), so not every intermediate form will have left fossil evidence. – jamesqf Feb 07 '17 at 05:48
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    Wow...Are some creationists spamming people to spread their believes now?! – Remi.b Feb 07 '17 at 07:52
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    That missing links are not found doesn't mean they are not there. Further, why on earth bother about spam? – AliceD Feb 07 '17 at 08:52
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    "and not by the stretching of the neck or any other bodily exercise." was never put forward by Darwin, instead, it was Lamarck's theory of Acquired characteristics. – Imtiaz Raqib Feb 07 '17 at 20:34
  • the three evolution videos from Stated Clearly are the best video explanations of evolution I have ever seen. I recommend watching them it will help you a lot. https://www.youtube.com/watch?v=0SCjhI86grU – John Feb 07 '17 at 22:39

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Darwin cited the giraffe as an outstanding example of natural selection. Supposedly, as a result of extended droughts, the supply of green leaves could be obtained only at the top of the trees, and therefore the shorter necked giraffe died off.

The term outstanding is funny in its usage here but otherwise this text is quite right so far.

However, there is no evidence whatever in the fossil record or elsewhere that giraffes with short necks have ever existed.

Actually there is. See this popular science article suggested by @James.

And what would have happened to young giraffes with relatively short necks?

The answer in the text above. It rightly says the shorter necked giraffe died off.

Darwin failed to realize that body characteristics in offsprings are determined and programmed by DNA factors of the Genes or the Genetic material of the parents [..]

This is an awfully phrased sentence making it very clear that the author has no idea about genetics.

not by the stretching of the neck or any other bodily exercise

Sure. The concept that individuals stretch their necks, necks become longer and this characteristic is passed on to the offspring is wrong indeed. This is known as Lamarckism. It is funny because the above text describe natural selection and it then says that it is wrong by making a straw man, misrepresenting natural selection as a Lamarckist process.

What is the current status of "theory of evolution of species" ?

You should have a look at the post Is evolution a fact?.

You should also have a look at an intro course to evolution. There are several online and free introductory ressource of information on evolutionary biology. Understanding Evolutionby UC Berkeley is probably one of the best. It is very short, very introductory and will already teach you a lot.

Community
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Remi.b
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Giraffe necks being long because of 'reaching' is false. The neck size is due sexual selection.

The writer of the paragraph fundamentally misunderstood Darwin, he never argued that the act of stretching of necks would make them longer in subsequent generations, that is Lamarkism, which is what Darwin argued against.

Darwin postulated that there exists some sort of information carrier which can be transmitted from parent to offspring. At the time there was no understanding of DNA or of any type of 'genetic material', all of early genetics actually was done statistically on abstract 'lines' of genes with no conception of DNA. Genetics as a field of study doesn't require a DNA model for genes.

Likewise, knowing what DNA is or isn't doesn't matter to the theory of evolution. Evolution is an intrinsic process of change in any system where there is heritable variation and selection. If you have self-assembling robots competing for a limited amount of scrap metal and which can make errors (and those errors are copied to future generations) they can be thought of as evolving.

Now given the restrictions on any system of heritability, variation and selection the result is evolution. Now the question is can evolution explain speciation that we see in the natural world.

I've studied genetics for just over 10 years and so far the answer has always been yes, it explains it amazingly well. There is no alternative theory or idea which can explain the observed variation in DNA between species, in cancer cells etc... as well as Darwinian evolution does.

Jack Aidley
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Artem
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  • In one of the posts here, some one wrote about the famous paper "Gould and Lewontin, the Spandrels of San Marco". Does that paper support Darwin's theory ? I have not read that paper; I came to know about it just few minutes ago. But looking all around, my view is that Darwin's theory is not accepted by ALL biologists. Is this my view correct ? Pardon me for my lack of biology knowledge. – atom Feb 07 '17 at 04:21
  • That paper is about another, what I think is more of a semantic argument in genetics. Does evolution act at the level of the entire holistic organism or does it act at the nucleotide. Regardless, there is no doubt that both sides are discussing the action of Darwanian evolution. – Artem Feb 07 '17 at 04:56
  • Also to clarify, my professional experience is that all geneticist I have met accept and apply Darwin's theory. I would make the analogy that evolutionary theory is as much a consequence of our universe as is the relation of force to mass * acceleration. – Artem Feb 07 '17 at 05:04
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    A few comments. While it might be true that neck size is under sexual selection, it is not quite the point that the post is trying to make. Also, you would need a reference to backup the claim that mate choice is based on neck size in giraffes. You slightly misrepresent evolution as being the result of natural selection only while several processes affect evolution (such as genetic drift typically). I am not sure I understand the point of highlighting that early evolutionary biologist knew nothing about the structure of DNA (it is true but arguably off-topic for the post IMO). – Remi.b Feb 07 '17 at 08:08
  • A few comments (suite). The sentence knowing what DNA is or isn't doesn't matter to the theory of evolution is quite misleading IMO. I am not sure either why you say "Now the question is can evolution explain speciation that we see in the natural world.". Also "Lamarckism", not "Lemarckism". – Remi.b Feb 07 '17 at 08:08
  • @remi.b I understand one can take a DNA-centric view of evolution and for all practical purposes that is correct. The point I'm trying to make is that evolution is a consequence of the properties of DNA based life, namely heredity, variation and competition. In that way one can know nothing about DNA but still understand the theory of evolution. Evolution is the process. – Artem Feb 07 '17 at 18:23
  • @Artem: And as a matter of simple fact, Darwin knew nothing about DNA (it wasn't discovered until a century later), or even Mendelian genetics. His theory was based on observation. Indeed, we could have evolution that's not based on DNA, as for instance self-reproducing machines. – jamesqf Feb 07 '17 at 19:31
  • @atom yes, the theory of evolution (whose modern version has, well, evolved enormously since Darwin's days) is absolutely accepted by the scientific community. There are some people (AFAIK exclusively in North America) who reject it but they are essentially considered crackpots by the broader community since they simply don't have any leg to stand on scientifically. – terdon Feb 09 '17 at 12:13
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The theory of evolution of species is about as solid as the theory of general relativity.. may even better considering that there are no known situations in nature that invalidate it unlike say... when general relativity meets the very small and encounters the theory quantum of mechanics.

The giraffid animal which had short neck... would not have been recognized as giraffe. it would have been the ancestral species to the giraffe. The closest living relative to a giraffe is the okapi. https://en.wikipedia.org/wiki/Giraffid

JayCkat
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