By Phys.org
The most characteristic feature of Darwin’s finches is the diversification of beak morphology that has allowed these species to expand their utilization of food resources in the Galápagos archipelago. A team of scientists from Uppsala University and Princeton University has now identified a gene that explains variation in beak size within and among species. The gene contributed to a rapid shift in beak size of the medium ground finch following a severe drought. The study is published in Science.
Darwin’s finches are a classical example of an adaptive radiation. Their common ancestor arrived on the Galápagos about two million years ago. During the time that has passed the Darwin’s finches have evolved into 18 recognized species differing in body size, beak shape, song and feeding behaviour. Changes in the size and form of the beak have enabled different species to utilize different food resources such us insects, seeds, nectar from cactus flowers as well as blood from seabirds, all driven by Darwinian selection. In a previous study from the same team the ALX1 gene was revealed to control beak shape (pointed or blunt) and now a gene (HMGA2) affecting beak size has been identified.
‘Our data show that beak morphology is affected by many genes as is the case for most biological traits. However, we are convinced that we now have identified the two loci with the largest individual effects that have shaped the evolution of beak morphology among the Darwin’s finches’, says Sangeet Lamichhaney PhD student at Uppsala University and first author of the study.
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51 comments on “Evolution in action detected in Darwin’s finches”
@OP – The medium ground finch diverged in beak size from the large ground finch on Daphne Major Island, following a severe drought in 2004-2005.
In drought conditions, they would probably become more specialised by dependence on the co-evolved Opuntia Cacti for food.
[http://bguile.northwestern.edu/env/cactus.html}(http://bguile.northwestern.edu/env/cactus.html)
There are several types of prickly pear cactus in the Galápagos. These cacti have flat pads with spines. Some islands have varieties that may grow as tall as 12 meters high and have trunks like trees. Other islands have varieties that grow in bushy short clumps. The prickly pear cactus on Daphne Major are usually 1 to 3 meters tall.
The prickly pear cactus produces green fruits and has yellow flowers 5 to 7 cm across. The cactus finches eat the seeds and nectar from the flowers and eat the fruit and seeds. The ground finches feed on the fruit and seeds of the cactus.
https://en.wikipedia.org/wiki/Opuntia_echios
Birds may well have brought the Cactus seeds to the islands in their guts!
Opuntia seeds in prickly pears, are particularly think shelled and resistant to digestion and damage.
A genus of salamanders is now in the early stages of incipient species formation, and maybe going though character displacement (see ensatina.net). One creationist wrote in and said “You can’t prove that!”
Given that creationists cannot recognise the evidence of evolution in millions of other species, their opinions on what constitutes “proof” is of negligible consequence!
Nothing new here.
Dr Lee Spetner questions Darwin’s ‘Natural Selection’ hypothesis in the light of accelerated evolution which has been observed with finches, cichlids, daisies, etc. Concerning Darwin’s finches he writes:
Spetner. The Evolution Revolution. p.75.
‘In 1967, about 100 identical finches were removed from a U.S. Government Bird Reservation in the middle of the Pacific Ocean and were taken about 300 miles away to a group of four small atolls lying within less than 10 miles of each other, which had no native finches. The birds were released onto one of these islands, and they soon spread to all of them. Seventeen years later, when the birds were first checked, they were found to have a variety of bill shapes and to be adapted – both by their behaviour and by their bill shapes and associated muscles – to various niches. This was a speeded- up form of the conventional scenario of Galapagos finch evolution. In seventeen years, and possibly less, the finches have diversified into various niches. If this diversification occurred in less than seventeen years, why did Darwin’s Galapagos finches have to take two million years? They could have done it much more rapidly, and perhaps they indeed did. The diversification can be accounted for by a built-in response of the finch’s genome to an environmental input as postulated in the NREH.’
I live within a short walking distance of these birds; I must book a viewing.
Short term selection of varietal differences or variation in a particular species, does nothing to challenge the masses of evidence of natural selection shaping millions of species over millions of years.
He is a mechanical engineer seeking to confirm his biblical preconceptions, so it is understandable that he does not understand biology!
BTW: Evolution by way of Natural Selection, is a scientific theory not just a hypothesis.
No scientific theory has ever claimed Natural selection, to be “random”. That is a creationist strawman.
Nothing unusual at all that some creationist is totally incompetent at interpreting biological observations.
What is being described her is evolutionary radiation sometimes called “adaptive radiation”.
Major changes usually take a long time, but genetically diverse populations rapidly expanding into a new habitat, are liberated from the selective pressures of the previous habitat, and are then selected according to the new opportunities available to them.
Lee Spetner also writes:-
The proximate biochemical signal evoking the change in beak shape [of Galapagos finches] has been discovered to be a protein growth factor Bmp4. The more Bmp4 that is made, the broader and deeper is the bird’s beak. This protein acts as a signal to the development of the craniofacial bones which determines the beak’s shape. If my suggestion is correct that the hormones triggered by environmental inputs affect embryonic development, then those hormones induce these growth factors to form the finch beak
and if his speculations are wrong, as is to be expected when creationist engineers make up their own versions of biology, the changes were triggered by mutant variations in hox genes which switch on and off the genes triggering beak development activating hormones, with the beak forms SUBSEQUENTLY selected by the feeding opportunities and survival of individuals and groups of birds.
These are indeed the early stages of evolution, during which genetic diversity within existing gene-pools, where speciation proceeds through the stages of varieties, and sub-species towards full speciation.
Considerable genetic diversity usually exists within populations, but the adaptations in Darwin’s Finches are much more extensive than simply a change in the shape of the beaks.
Their initial adaptation was probably much slower, as it is unlikely that as many as a hundred, would arrive by chance weather events at such a remote location, so the genetic diversity would have been much less.
The “environmental input”, IS the natural selection, acting on the effects of pre-existing and on-going mutations.
Lee Spetner, simply fails to understand the mechanism, gets the causes of the changes backwards, and then flips back in denial of the natural selection acting on random genetic mutations, to his biblical gap-filler for an explanation.
‘BTW: Evolution by way of Natural Selection, is a scientific theory not just a hypothesis.’
Both Perry Marshall (Evolution 2.0) and John Sanford (Genetic Entropy, and the Mystery of the Genome) totally shred the theory of Natural Selection. Marshall does so by emphasizing the importance of epigenetic controls in evolution, and the comparison of DNA to computer code; an area where he is an expert.
Sanford also dismisses Natural Selection as an agent of improving change since it cannot select at the molecular level; its function is to weed out the less able, the disabled, and the old and sick. It is practically useless in selecting, extremely rare, good mutations.
Of more interest, Sanford explains the puzzle of genetic entropy over ‘millions of years’.
Both books are worth reading, and contribute to the evolution/creation debate. Marshall is a theistic evolutionist whereas Sanford is a creationist. He started out as an evolutionary atheist. Sanford understands biology, and was a prolific inventor in related areas.
‘BTW: Evolution by way of Natural Selection, is a scientific theory not just a hypothesis.’
I’m afraid, that for professional biologists, these claims are laughable, and would fail even school level biology!
Regardless of if he has expertise in computer code, he obviously has no competence in genetics, or he would know that DNA bears no resemblance to computer code!
There are no “epigenetic controls” in evolution. Epigenetics is about short-term temporary carry-overs of genetic features, which have failed to reset at fertilisation. They fade out after one or two generations.
Whole organisms function “at molecular level”, so any selection of organisms removes or selects at all levels. This is simply a nonsensical assertion on his part.
This claim is an oxymoron! Removing weaker competitors is what liberates resources to promote the growth and reproduction of beneficial mutations.
What puzzle?
Entropy is explained by the second law of thermodynamics!
That is a political debate not a scientific one. The science of evolution happening by way of natural selection has been confirmed many thousands of times, in high integrity competent university studies – reviewed by expert biologists.
These books are just the personal opinions of those who cannot understand the science or who are in denial of the science.
Neither theistic evolution, nor creationism is science.
Both are theology which is simply not compatible with science – despite assertions to the contrary!
No doubt he invents many ideas – its just that they are ideas which fail whenever tested by reputable science departments! (That does not mean he cannot invent gadgets etc. using science from unrelated subjects.)
These books may impress amateurs, but when presented to scientific journals for expert review, they usually don’t even make it to the starting line – because they fail at the level of high-school science!
As far as refuting the massive volume of evidence of evolution/natural selection goes, they might just as well decide to refute gravity and then step out of a tenth-floor window to test their “new science”!!
Your time would be better used studying some standard biology text-books, rather than this whimsical stuff!
Ben #8
Just to headline Alan here, this is a list of profound misunderstandings. Spectacular bunk.
To add to the entropy argument. The misunderstanding comes from the schoolboy error of not noticing that entropy increases in closed systems. We are bathed in the most momentous flux of energy from the sun. We are very far from in a closed system. Schrodinger gave a fuller treatment back in 1967.
http://whatislife.stanford.edu/LoCo_files/What-is-Life.pdf
‘What puzzle?
Entropy is explained by the second law of thermodynamics!’
These are the perplexing questions to which Sanford proposes an answer:
‘A S Kondrashov. 1995. Contamination of the genome by very slightly deleterious mutations: Why have we not died 100 times over? J. theor. Biol. 175:583-594.
A. Eyre-Walker and P. Keighley.1999. high genomic deleterious rates in Hominids. Nature 397: 344-347.
”..deleterious mutation rates appear to be so high in humans and our close relatives that it is doubtful that such species could survive…”
Loewe, L. 2006. Quantifying the genomic decay paradox due to Muller’s ratchet in human mitochondrial DNA. Genet. Res. Camb 87:133-159.
”A surprisingly large range of biologically realistic parameter combinations should have led to extinction of the evolutionary line leading to humans within 20 million years…”
Kondrashov’s puzzled question is asked again and again in different forms by such as Crow, Higgins & Lynch, Hoyle, etc. 1995.’
Incidentally, have you read either of the authors I have cited? Marshall, as a marketing expert, is certainly engetically pushing his work online. Also he also offers a huge monetary reward to anyone who can refute his thesis; but no takers yet. Icertainly believe that he argues conclusive that DNA is a code needing a programmer.
Thanks Alan and Phil; it’s refreshing when visiting RDFRS to now and then get a reminder of what’s what.
It seems that religious faith can render people incorrigible.
Sorry, not 1967. 1944. A Cambridge publication of it was in that year. Schroedinger allegedly died in 1961, but maybe someone forgot to open the box to check?
So many christian preachers refer to evolution as strictly random changes, so how can such a complex organism or organ possibly evolve by “random” changes alone? That demonstrates the abysmal ignorance they have for the many theories evolutionary biology.
I have read that kind of shallow thinking many times. Those of us here who have an understanding of the mechanisms of evolutionary biology, know well that mutations may be random, but natural selection is NON random ( nonrandom survival, nonrandom mating, and nonrandom fecundity). The interactions between random mutations and nonrandom natural selection is the basis for evolutionary change. That concept is clear and obvious.
Ben #11
Ben the questions posed in your other references are countered by mathematical modeling of necessary mutation rates (too low we die out, too high we die out) and finding in acttuality they match these models jolly nicely. This is a multiskilled task, needing maths, computing and biological capabilities. If you can reference the teams behind any of these chaps I would be grateful.
If this is about gene multi-functionality and the loss of some sub-set of functions, that is now reliably covered in the work of Andreas Wagner (see Arrival of the Fittest covering his Swiss team’s work in the field). It transpires that the entire solution space of proteins, for instance offer something up to a millionfold more functional proteins to do a specific function than was imagined and that these solutions lie in meshes across the solution space (however organised) . This greatly relieves the evolutionary burden for multi-function genes as the meshes create stable pathways for the maintenance of one function whilst further functions may be sought (or rather, stumbled into). A converse way of viewing this is the millionfold reduction that a mutation will be catastrophic. (Mutations will mostly be catastrophic, but now in demonstrably survivable numbers.)
No scientific theory has ever claimed Natural selection, to be “random”. That is a creationist strawman.
As I understand it, natural selection works by means of the non random survival of randomly occurring self replicating information.
The mutations which survive do so because they enable the genotypes within which they have taken place to succeed phenotypically.
I think!?
Oh well, I’ll just have to wait and see if the Damoclean sword drops.
‘What puzzle?
Entropy is explained by the second law of thermodynamics!’
The answers are in standard physics textbooks, and even on Wikipedia!
It is very easy to understand why deleterious mutations do not cause species to die out!
Millions of sperm in any ejaculation, have deleterious mutations – so they fail in the competitive race to fertilize human eggs.
Similarly many eggs and zygotes in humans which are not viable, or carry deformities, spontaneously abort.
(70% of the total of fertilized human eggs do not develop to the point of birth.)
Only the fittest ones make it to birth! (It’s a form of natural selection)
As I said earlier, the information is in standard biology (and medical) textbooks.
There is no need to seek out whimsical notions from the ignorant and incredulous who ask questions THEY do not understand, and who have urges to promote their daft speculations in books written to impress the uninformed!!
He probably believes it himself, and argues with the sincerity of self-delusion!
In order to make effective use of scientific papers, it is necessary to understand the basic science behind the investigative methods.
It is not possible for such authors to understand information taken from PhD science papers, while they fail to understand high-school biology – hence the arguments from incredulity.
I’ve just accidentally “liked” on of my own comments, when I meant to like someone elses!
Didn’t think that was possible; shouldn’t be really.
‘As I said earlier, the information is in standard biology (and medical) textbooks.’
You cannot be serious? Seriously?
You seriously delude yourself and try to delude everyone else if you think that all those geneticists cited above (from A S Kondrashov to Loewe) need do is consult a few standard biology textbooks. Wise up:-)
I suggest that before you make any further silly responses you read both Sanford and Marshall; as obviously you haven’t.
‘As I said earlier, the information is in standard biology (and medical) textbooks.’
I can assure you I am serious.
What I said was that creationists READING the work of geneticists needed to understand basic evolutionary biology in order to grasp what was being said in science papers.
Sanford and Marshal cannot be competent biologists if they are making the claims you quote, as these illustrate a profound ignorance of the subject!
It is like Flat Earthists claiming the be expert astronomers!
Why should I take their claims seriously when there are thousands of peer-reviewed papers on evolutionary biology and genetics which contradict their unevidenced claims?
The consensus of geneticists clearly supports neo-Darwininan evolutionary theory!
@OP – Changes in the size and form of the beak have enabled different species to utilize different food resources such us insects, seeds, nectar from cactus flowers as well as blood from seabirds, all driven by Darwinian selection. In a previous study from the same team the ALX1 >gene was revealed to control beak shape (pointed or blunt) and now a gene (HMGA2) affecting beak size has been identified.
‘Our data show that beak morphology is affected by many genes as is the case for most biological traits. However, we are convinced that we now have identified the two loci with the largest individual effects that have shaped the evolution of beak morphology among the Darwin’s finches’, says Sangeet Lamichhaney PhD student at Uppsala University and first author of the study.
This quote based on study data is clear language scientific unlike the vague suggestions about unspecified “environmental inputs” during embryonic development (in the egg) -as if hormones and growth are not governed by genes selected by ancestral history!
@#7 -Lee Spetner also writes:- If my suggestion is correct that the hormones triggered by environmental inputs affect embryonic development, then those hormones induce these growth factors to form the finch beak
If it had any scientific credibility, he would get it published in a scientific journal! Anybody can publish nonsense on a blog!
‘Sanford and Marshal cannot be competent biologists ..’
Marshall is not a biologist. Sanford, who is a competent geneticist, was persuaded to creationism as a consequence of a determination to follow wherever an evaluation of the facts led; and it led to creationism. He began his search as an atheist.
see https://en.wikipedia.org/wiki/John_C._Sanford.
In ‘Genetic Entropy, and the Mystery of the Genome’, Sanford writes ‘The Primary Axiom[TOE] is actually an extremely vulnerable theory. In fact it is essentially indefensible. It’s apparent invincibility derives largely from bluster, smoke, and mirrors. A large part of what keeps the Axiom[TOE] standing is an almost mystical faith that the “true-believers” have in the omnipotence of natural selection. Furthermore, I began to see that this deep-seated faith in natural selection ‘is typically coupled with a degree of ideological commitment which can only be described as religious. I started to realise (again with trepidation) that I might be offending the religion of a great number of people!
In the Foreword it is stated that:
The author concludes that most professional biologists today are just like he was earlier in his career. Most simply are not aware of the fundamental problems with the Axiom. This is because the Axiom’s fundamental assumptions are not critiqued in any serious way, either in graduate classes, or in graduate level textbooks, or even in the professional literature.
Most biologists today are unaware that the claims of population genetics to which they were exposed in
graduate school can no longer be defended from a scientific standpoint. Most, therefore, can hardly imagine that when realistic assumptions are applied, population genetics actually repudiates the Axiom.’
‘As I said earlier, the information is in standard biology (and medical) textbooks.’
While thermodynamics is in physics textbooks.
If you are going to use citations to claim scientists support your arguments, you are going to have paste quotes of the evidence (if you can find any) they present which does so.
When your claims contradict standard textbooks and thousands of university level science papers, such vague citations lack credibility!
It gives the impression you are just cutting and pasting stuff from dubious sources, or which you do not understand!
You do not seem to understand the concept of ‘genetic entropy’ to which Sanford is alluding. The following quote may be helpful in focussing on the problem raised by Kondrashov, Loewe, and other competent geneticists. These are atheistic evolutionists.
Sanford. Genetic Entropy, … P.45.
‘The consensus among human geneticists is that, at present, the human race is genetically degenerating due to rapid mutation accumulation and relaxed natural selection pressure (Crow, 1997). These geneticists realise that there is presently a net accumulation of mutations in the population and that it is occurring at a much higher rate than was previously thought possible. Geneticists widely agree that these mutations are essentially either neutral or deleterious (if they are beneficial, they are considered so rare as to be entirely excluded from consideration). Subsequently, they realize that genetic information is currently being lost, which must eventually result in reduced fitness for our species. This decline in fitness is believed to be occurring at 1-2 per cent per generation (Crow, 1997)’
‘If you are going to use citations to claim scientists support your arguments,
‘Sanford and Marshal cannot be competent biologists ..’
Marshall is not a biologist. **Sanford, who is a competent geneticist*, was persuaded to creationism as a consequence of a determination to follow wherever an evaluation of the facts led; and it led to creationism.
Nope!
Facts and evidence do not lead to creationism. Science denial, personal incredulity, and self deception lead to creationism!
(This is too complicated for me to understand, so god-did-it-by-magic!)
Stamford may have had some competence as a genetic technician and a plant breeder at one time, but he has no grasp of the grand-scale over-view of science!
https://en.wikipedia.org/wiki/John_C._Sanford
Which means he scores “Z minus” for cosmology, astronomy, geology, planetary sciences, nuclear physics, evolutionary biology, and palaeontology!
Ah! The old junkyard claim illustrating a total lack of understanding of evolutionary genetic mechanisms in which failed variations in millions of varied offspring die out and those with small advantages increase in numbers , gradually developing improved support from the current environment.
wikipedia.org/wiki/Kansas_evolution_hearings – The scientific community rejects teaching intelligent design as science; a leading example being the United States National Academy of Sciences, which issued a policy statement saying “Creationism, intelligent design, and other claims of supernatural intervention in the origin of life or of species are not science because they are not testable by the methods of science
Science is about taking a joined up view about the workings of the world and the universe.
Denial of some small area of well evidenced science, usually leads to conflicts with all the other specialist areas, which are also supported by massive evidence!
‘If you are going to use citations to claim scientists support your arguments,…’
These scientists do not support my arguments. Rather they are stumped for an answer to the measurable genetic deterioration. They are all at a loss as to why we are still around if we have been evolving for millions for years. The problem seems clear to me, and to anyone else to whom I have explained it. You are just prevaricating and being deliberately obtuse.
You practice the old tactic of; ‘if you can’t get the ball, get the man.’
http://www.internationalskeptics.com/forums/showthread.php?t=161310
Ah! The “you’re just a biologist who doesn’t understand this profound creationism argument Stamford has made up”!!!
I know that “entropy” is an impressive sciency word, but it does actually have a scientific meaning, which Sanford has obviously missed due to being a physics duffer who does not know how to calculate the age of the Earth!
http://physics.bu.edu/~duffy/py105/Secondlaw.html
.The second law of thermodynamics is one of the most fundamental laws of nature, having profound implications. In essence, it says this:
The second law – The level of disorder in the universe is steadily increasing. Systems tend to move from ordered behavior to more random behavior.
One implication of the second law is that heat flows spontaneously from a hotter region to a cooler region, but will not flow spontaneously the other way. This applies to anything that flows: it will naturally flow downhill rather than uphill.
The “genetic entropy” to which Sanford is alluding, is fiction he made up and put into a computer programme having mis-defined various genetic features! He laughably calls this “evidence”!
This is cherry picked junk! There is plenty of starvation and selection pressure in many parts of the world.
No they don’t! It is inherited beneficial or stable genes, mutations which matter to the survival of the species. Dead sperm and aborted zygotes don’t count!
This is nonsense, but even if it was true and the human race became extinct, it is not an argument against the age of the Earth or the generality of biological evolution in the history of all species.
There is no reason to believe that the loss some information will reduce fitness (A word Stanford does not understand in an evolutionary context), and there is no reason to assume that mutations are unable to create new information or preserve existing information. Vast numbers of studies of genomes clearly show that this happens.
‘These geneticists realise that there is presently a net accumulation of mutations in the population and that it is occurring at a much higher rate than was previously thought possible. Geneticists widely agree that these mutations are essentially either neutral or deleterious
No they don’t! ‘
You are into denial; with a plethora of exclamation marks!! which is a sign of desperation. All these geneticists wrong? Go on 🙂
Here is another quote from Sanford, and a pertinent question.
J Sanford. Genetic Entropy … p. 150.
‘If the Primary Axiom is wrong, then our basic understanding of life history is also wrong (see Appendix 5). If the genome is degenerating, our species is not evolving. There appears to be a lose parallel between the ageing of a species and the ageing of an individual. Both seem to involve the progressive accumulation of mutations. Mutations accumulate both within our reproductive cell lines and our body cell lines. Either way, the misspellings accumulate until a threshold is reached when things rapidly start to fall apart. This results in a distinct upper range for lifespan. Human life expectancy presently has an average of about 70 years with a maximum near 120. However, when first cousins marry, their children have a serious reduction of life expectancy. Why is this? It is because inbreeding exposes the genetic mistakes within the genome (recessive mutations) that have not yet had time to “come to the surface”. Inbreeding is like a sneak-preview of where we are going genetically as a species. The reduced life expectancy of inbred children reflects the overall aging of the gnome, and reveals the hidden reservoir of genetic damage (recessive mutation) that has been accumulating. If all this genetic damage were exposed suddenly (if we were all made perfectly inbred and homozygous), it would be perfectly lethal. We all would be dead. Our species would instantly become extinct.
‘Genetic damage results in ageing, and ageing shortens lifespan. This is true for the individual and for the population.’ logically we should conclude that if all of this is true, then at some time in the past there must have been a time when there was less genetic damage in the genome, and thus longer lives, and less deleterious effects from inbreeding. Is there any evidence of this?’
Question: Was there less genetic damage in the past, in our distant ancestors, or in your or my life personally?
‘If you are going to use citations to claim scientists support your arguments,…’
It looks like Stamford has been quote mining, and you really have no idea what you are talking about, or what the cited articles are saying!
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1461475/pdf/11139491.pdf
THE rate at which spontaneous mutations occur and
the frequency distribution of their effects on fitness
are of interest both as basic parameters of population
genetics and as important factors in the evolution of
such diverse features as life histories, sex and recombination
mate choice, and senescence (Kondrashov -1998;LYNCH el al 1999)
Until quite recently, the only available estimates were based on experiments with Drosophila melanogaster (Mukai 1964; Mukai et al. 1972; Ohnishi 1977) in which mutations were allowed to accumulate on second chromosomes that were sheltered from selection. The results were interpreted as indicating a relatively high U min of
1 per genome per generation, with an average reduction of viability of 1–2% per mutation (Simmonds and Crow 1977).
However, this interpretation has been challenged by reanalyses of the D. melanogaster data – (Keightley 1996; Garcia-Dorado 1997;
Caballero and Keightley1998)
Do you know what Drosophila melanogaster is?
No they don’t! ‘
No they are not wrong but Sanford’s quote-mining and misrepresentation of their work is utterly wrong!
Genetic Entropy is pseudo-science made up by Sanford!
Which is simply his repeatedly asserted denial of evolution!
He is grasping at straws to prop up his egotistical delusional views of humans as the central feature of the universe!
A degenerating genome is still evolving – He has no idea what he is talking about!
The vision of Blind Cave-Fish degenerates, but that is still evolution!
Parasites lose many of their independent features- but that is still evolution!
The book is pseudo-science rubbish which no reputable scientific bodies accept!
Which is why playing with nuclear waste, or exposing skin to tropical sun at high altitude, is a bad idea!
Do you have any evidence about the historical and geographical levels of genetic damage to animal populations – is is this just guessing?
Or any evidence that there was more or less inbreeding when the human population was a tiny fraction of its present size for thousands of years?
This being a science site, some of us know about such things.
https://en.wikipedia.org/wiki/Toba_catastrophe_theory
The Toba eruption has been linked to a genetic bottleneck in human evolution about 50,000 years ago,[33][34] which may have resulted from a severe reduction in the size of the total human population due to the effects of the eruption on the global climate.[35]
According to the genetic bottleneck theory, between 50,000 and 100,000 years ago, human populations sharply decreased to 3,000–10,000 surviving individuals.[36][37] It is supported by genetic evidence suggesting that today’s humans are descended from a very small population of between 1,000 and 10,000 breeding pairs that existed about 70,000 years ago.
This is a thorough going set of takedowns of Sanford’s nonsense from 2006.
Though really the work of Wagner in its effect super nails these nineteenth century ideas of devolution.
As Alan points out, to add a direction to evolution is to completely misapprehend the process by presupposing some intended outcomes of a creator. The the concept of regress springs from this unspoken premise.
‘A degenerating genome is still evolving – He has no idea what he is talking about!
The vision of Blind Cave-Fish degenerates, but that is still evolution!
Parasites lose many of their independent features- but that is still evolution!’
The rather apologetically specious use of the word evolution which evolutionists are inevitably forced to fall back on; but accurate. It is all downhill. I remember watching years ago when Dawkins appeared on TV with the Pratt family to argue for pigeon-breeding as an example of evolution; but he failed to say that it was all downhill! Similarly with dog-breeding. You could breed pure-bred poodles for 100 years, and you would never get back to the original information-rich wolf kind. True or False?
Aubrey De Grey is attempting to deal with the problem of mutational decay with the hope of living to be 1,000 yrs. old. The biblical Methuselah would have been almost mutation-free at the outset, and made it to 960 yrs. De Grey’s thinking about genetic entropy is correct, but generally his attempts to get rid of ageing is not met with much enthusiasm among geneticists.
I repeat the question which you never answered: Was there less genetic damage in the past, in our distant ancestors, or in your or my life personally?
Aubrey de Grey would answer Yes!
Reading Sanford’s ‘Genetic Entropy, and the Mystery of the Genome’ would hopefully resolve your misquoting problems, and attempts to wriggle out of the serious questions which he raises.
I see another post @#34, repeating Sanford’s nonsense, but just like my other references to biology or sciences, my question @30 remains unanswered.
@#30 -Do you know what Drosophila melanogaster is?
Having looked for the cited science papers which Sanford/Ben claim support his speculations, I find that the “evidence” for genetic degeneration comes from studies on Drosophila, where damaging mutations were deliberately induced and retained in the lab populations, in order to demonstrate the evolutionary origins of specialist organs.
For example certain mutations can cause legs to grow in place of antennae!
Claiming that genetic studies on Drosophila “disprove evolution” would be pure comedy, if it were not for the fact that this garbage is being used to con the uneducated and damage children’s understandings of science!
‘A degenerating genome is still evolving – He has no idea what he is talking about!
The vision of Blind Cave-Fish degenerates, but that is still evolution!
Parasites lose many of their independent features- but that is still evolution!’
This comment shows that you have zero understanding of the biological mechanisms of evolution, and need to do some serious work on basic textbooks!
You have just given an example of (in this case human) selection creating new races or subspecies.
When species separate and branch according to life-style of geography, once the accumulation of genetic mutations and loss of earlier genes makes back-crossing infertile, they are two separate species.
While because of size, miniature dogs cannot cross breed with wolves, but the larger breeds can and do.
Likewise, wild branches of the Canids can also cross breed with wolves. or dogs. -( Jackal–dog hybrid, Coywolf etc.)
As mutations are lost or gained species branching on the tree of life, cross-bred offspring gradually become less fertile, until eventually they are sterile hybrids (such as the mule), or the cannot interbreed at all.
. . . In your asserted personal opinion – as someone demonstrating a profound ignorance of evolutionary genetics, who is making it up as he goes along, or copying from ignoramuses!
The “problem of mutational decay” is a creationist fantasy which was debunked decades ago. The variable rates of mutation and their effects have been studied for decades by biologists. There is no direction or “one direction” in evolution.
I have pointed out @26, Sanford’s denials and incompetent assertions about a whole string of sciences.
@#26 -Which means he scores “Z minus” for cosmology, astronomy, geology, planetary sciences, nuclear physics, evolutionary biology, and palaeontology!
.. . . and he is no longer following the scientific methodology which provides accurate information by using rigorous methods, independent reviews and checks, honesty, and integrity. He is just selling stories, containing fanciful thinking and long refuted claims.
Perhaps some studies on the authorship and historical origins of “The Bible“ would also not come amiss.
Laughable Biblical claims based on bronze-age ignorance, usually have no credibility with informed experts who understand which mechanisms (such as telomeres) are involved!
Rates of mutation vary, as do rates of selection, as Phil explained to you @#15 – referring you to the works of Andreas Wagner.
There is no “one size fits all” spanning populations separated by thousands of miles and tens of thousands of years.
Also, if you had any understanding of the studies on Drosophila which Sanford spuriously claims support his nonsense, you would recognise that the work of geneticists refutes his claims!
[#25]
Hi ben drogan,
Alexy Kondrashov (the one in your reference to Kondrashov, Loewe) is most famous for debunking John Sanford’s genetic Entropy argument. As I understand the science, and history, one of Alexey Kondrashov’s famous works is called the Kondrashov Hypothesis. I don’t believe Kondrashov was directly addressing Sanford with his hypothesis – it’s just that Sanford’s take on genetics was left hanging by the development of the Kondrashov Hypothesis.
The Kondrashov Hypothesis, also known as the deterministic mutation hypothesis, explains the benefits of sexual reproduction.
The hypothesis begins: There is a slightly deleterious effect of mutations on a population (within a species) even with a small number of mutations. Here is where the link to Sanford begins … and ends.
Two scientists, Crow and Kondrashov, wrote papers in which they pointed out the above assumption led inexorably to the idea that all organisms were doomed to extinction in a relatively small number of generations. But we know this isn’t true from even the most trivial observations. Some species, including us with our recorded history, have been alive for a number of generations that is many orders of magnitude greater than this limit.
This led Kondrashov to study why this assumption was wrong. Scientists noted that the assumption worked in some simplified models – perhaps leading Sanford astray (here is Sanford’s “paradox”). Kondrashov, meanwhile, was motivated to think on: Why is this assumption so wrong, and how should we replace it?
The Kondrashov Hypothesis goes on to demonstrate the recombination effect of sexual reproduction on genotypes. This describes how breeding gives rise to some individuals with fewer deleterious mutations, and some with more. There is obviously a major disadvantage to individuals with more mutations (natural selection in action) and these individuals tend to die before they reproduce. This major selective disadvantage to individuals with more mutations thus weeds out those mutations from the population.
If you’re really interested in genetics and evolution I recommend a course on Epistasis. Here is another excellent primer – a scientific paper that reviews Mutation and the Evolution of Recombination from the Royal Society.
Peace.
I’ve just remembered; partly due to the introduction of garden bird feeders in the UK in the fifties, Black Cap beak evolution, has obviated the need for those with long thin ones, which can penetrate the netting and reach the food, to fly south to over-winter; and indeed, some are now found as far north as Finland; so this is neither new or surprising.
It is an example of evolution occurring before our very eyes, if we but choose to, OBSERVE IT!
Or, to lapse into vulgar vernacular, extricate our heads from of our arses.
37 – Addendum.
I should add that, obviously, sexual reproduction has the same effect on advantageous mutations – by which improvements are added to the genotype.
However, advantageous adaptation (from advantageous mutations) will tend to lead to the successful survival and reproduction of those genes so those genes are spread in the genotype.
This is, of course, perfectly in line with the theories of sex. The cost of sex is that we (and all other individuals in sexually reproducing species) only get to pass on 50% of our genes. The advantage is that our children are more likely to pick up advantageous mutations – from a probability point of view.
Peace.
I have noticed that inland living seagulls, now seem to stay inland for the whole year, and don’t migrate back to the coast to breed. I’m wondering if eventually they will speciate from those gulls that still migrate – but only if mating takes place inland thus creating a sexual selection situation.
facinating stuff!
That is simply wrong!
It’s not “all down hill!
That is the basis for Sanford’s asserted nonsense based on his lack of understanding of the physics of entropy and energy flows.
Rivers flow downhill, so those taking a blinkered view could erroneously conclude that all the water will drain out of them and the flow will stop – as water does not flow uphill! They may even find examples of studies of rivers in Saharan Africa where rivers dry up periodically.
The school boy error, they fail to understand about about the water cycle, is that, as the Earth is not a closed system (phil rimmer #10).
Like biological food chains, there are inputs of energy (reversing entropy locally) from the Sun powering rain clouds to carry water back up to the hills at the river’s sources.
John Sanford’s claim of “all downhill Genetic Entropy“, far from being an expert scientific theory, is simply a statement of personal incompetence by a schoolboy level physics duffer, showing that he does not understand (or dishonestly misrepresents), the entropy explained in the Second Law of Thermodynamics, and has omitted the energy inputs and effects of entropy from the Sun, from his supposed calculations.
Any competent scientist would promptly notice this, and dismiss his claims as deeply flawed, – which is why he is trying to sell the notion to the uneducated public on blogs and in books, instead of submitting it for review and publication by competent scientific journals.
https://en.wikipedia.org/wiki/Entropy
Most understand entropy as a measure of molecular disorder within a macroscopic system. The second law of thermodynamics states that an isolated system’s entropy never decreases. Such a system spontaneously evolves towards thermodynamic equilibrium, the state with maximum entropy. Non-isolated systems may lose entropy, provided they increase their environment’s entropy by that increment. Since entropy is a state function, the change in entropy of a system is constant for any process with known initial and final states.
Have a look at this link:-
https://en.wikipedia.org/wiki/Ring_species#Larus_gulls
A classic example of ring species was the Larus gulls’ circumpolar species “ring”. The range of these gulls forms a ring around the North Pole, which is not normally transited by individual gulls.
@ #5 – I live within a short walking distance of these birds
Me confused, which birds?
I must book a viewing
Read an article that bird-watching is on a list of “creepy” activities, sounds reasonable.
I once stood stock still at an intersection, listening to a northern mockingbird sing (they are most comfortable with high, artificial perches). Then noticed a police car at the light – hmm, what is that person doing?, lol.
bonnie @ # 2.
Me confused, which birds?
Darwin’s Finches; they’re curated near where I live, and you have to make a booking to see them.
Book ’em Danno!, turn to the right…
To ben #29:
These geneticists realise that there is presently a net accumulation of mutations in the population and that it is occurring at a much higher rate than was previously thought possible. Geneticists widely agree that these mutations are essentially either neutral or deleterious.
“No they don’t! “
Yes, they do. Most (not all) of those infrequent mutations are either neutral or deleterious. In many populations, stabilizing selection is occurring. For a random mutation to occur that s favorable in very unlikely and usually will be selected against in a particular environment. Neutral mutations are neutral because selection does not act on the phenotype that is a result of that mutation.
@25 – Geneticists widely agree that these mutations are essentially either neutral or deleterious (if they are beneficial, they are considered so rare as to be entirely excluded from consideration). Subsequently, they realize that genetic information is currently being lost, which must eventually result in reduced fitness for our species.
This was a selected pasted quote picked from my comment @28. (see below)
“No they don’t! “
@28 – No they don’t! It is inherited beneficial or stable genes, mutations which matter to the survival of the species. Dead sperm and aborted zygotes don’t count!
From my original comment it is clear I am talking about genes passed on to future generation after expressed deleterious ones have been weeded out. Not the initial rate of mutation.
It was also in the context of challenging this assertion (below), which is part of the Sanford denial of beneficial mutations leading to evolutionary changes, and the “all down hill from created perfection” “de-evolution error”, in denial of genetic balance being maintained.
Alan @ #42 – All fascinating stuff, I’ve always been fond of gulls, they always seem to glare at you with a kind of alien malevolence, which suggests that they would definitely peck your eyes out if they got half the chance!
While blatantly fatal expressed mutations are clearly deleterious, it is far from clear cut in a minority of cases, as to whether mutations are deleterious or not. Many could be regarded as a library of potential variation, from which future selections can be made when environments change.
This is the omission which leads creationists to the “all downhill” error, by denying or ignoring the balancing effects of natural selection in removing deleterious mutations when they are expressed in the phenotype .
That is certainly so when a mutation is expressed in a stable environment, but if it is neutral (pending further mutation on that DNA strand) or is recessive, it can be carried forward to a time when the organism has moved or the environment has changed.
It is this accumulated bank of altered DNA which creationists try to pretend has existed since the “creation” of the organism a few thousand years ago.
It is in fact further mutations swapping mutated sections of DNA, and the effects of sexual reproduction Phil mentioned, which give rise to the diversity on which selection acts (with massive mortality rates in organisms which produce large numbers of offspring).
To Alan4 #49: with respect to mutations…
Of course that is correct. But also, some deleterious mutations may only be slightly deleterious and not strongly affected by selection. In addition, there may be mutations that are carried from one generation to the next because of a pleiotropic effect, that is that a particular mutation may have a deleterious effect on the phenotype but has also a beneficial effect on another aspect of that phenotype which has a high selective value. Also there are cases that are probably preadaptive in nature.
The picture in the OP reminds me of the variations in spination in Cacti – particularly in island and coastal species.
Cactus spines are the evolutionary modified leaf-stalks which have had photosynthesising leaf surfaces reduced to zero to reduce water loss.
The barbed spines and glochids, give protection from browsing animals, but also spine density regulates the intensity of sunlight hitting photosynthesising stems, and gives variable protection from dying winds and wind-blown sand, as well as collecting sea mists from the atmosphere when winds blow these ashore.
Some forms of spination can also unhelpfully protect small sap-sucking insects from birds, by effectively providing a spiked roof over them.
In extreme climates, the balance of advantage to the plants from these features, can vary considerably locally.
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