Archive for the ‘Evolution’ Category

Raging biodiversity – “One trillion species on earth”

May 3, 2016

A new paper now estimates that there could be up to one trillion species on earth.

Kenneth J. Loceya, and Jay T. Lennona. Scaling laws predict global microbial diversity. PNAS, 2016 DOI: 10.1073/pnas.1521291113

It seems logical to me that for any environment there has to be an optimum (perhaps many possible such) number of species for the sustainability of those species. Biodiversity is not always good and the current “wisdom” that increasing biodiversity is always a good thing, is not just flawed – it is plain stupid. Evolution is highly inefficient (though it has been effective) and produces far more species than are necessary for the sustainability of life. Since over 99% of all species that have ever existed are now extinct, it follows that evolution has failed every one of those extinct species; and failed each to the point of destruction. Mass extinctions are merely the way in which the detritus of failed evolution is cleaned out. Currently probably some 30% of all species need to go extinct.

I have never yet heard a satisfactory explanation of why ever-increasing biodiversity, which is so politically correct, is a good thing. “The good of the eco-system” is often quoted – but what on earth is that? Is it better to have a multitude of species or a multitude of individuals in a fewer number of species? Is it better for external forces to change an environment (long, slow geologic processes or short sharp catastrophic events) or for the species within the environment to change it? There is a mindless worship of biodiversity which is not logical.

It seems almost self-evident to me that, for any given environment there must be an optimum number of species, with particular combinations of characteristics, which allow the ecosystem or biosphere to be in a self-sustaining equilibrium (not growing or declining but self-sustaining). This optimum will vary depending upon the characteristics and interactions between the particular species existing and the available space in the prevailing environment. Then, having fewer than the optimum number of species in that environment would mean that all the complex interdependent, interactions between species that seem to be necessary for sustaining each of the participating species would not be fully developed. I say “seem” because it is not certain that all interdependencies are necessarily of benefit to individual species. “It is the entire ecosystem which benefits” I hear some say, but even that is more an assumption than a conclusion.

 

The press release from the University of Indiana

Earth could contain nearly 1 trillion species, with only one-thousandth of 1 percent now identified, according to a study from biologists at Indiana University.

The IU scientists combined microbial, plant and animal community datasets from government, academic and citizen science sources, resulting in the largest compilation of its kind. Altogether, these data represent over 5.6 million microscopic and nonmicroscopic species from 35,000 locations across all the world’s oceans and continents, except Antarctica. ……

….. Microbial species are all forms of life too small to be seen with the naked eye, including all single-celled organisms, such as bacteria and archaea, as well as certain fungi. Many earlier attempts to estimate the number of species on Earth simply ignored microorganisms or were informed by older datasets that were based on biased techniques or questionable extrapolations, Lennon said. ……

……. The study’s results also suggest that actually identifying every microbial species on Earth is an almost unimaginably huge challenge. To put the task in perspective, the Earth Microbiome Project — a global multidisciplinary project to identify microscope organisms — has so far cataloged less than 10 million species.

“Of those cataloged species, only about 10,000 have ever been grown in a lab, and fewer than 100,000 have classified sequences,” Lennon said. “Our results show that this leaves 100,000 times more microorganisms awaiting discovery — and 100 million to be fully explored. Microbial biodiversity, it appears, is greater than ever imagined.”

Abstract

Scaling laws underpin unifying theories of biodiversity and are among the most predictively powerful relationships in biology. However, scaling laws developed for plants and animals often go untested or fail to hold for microorganisms. As a result, it is unclear whether scaling laws of biodiversity will span evolutionarily distant domains of life that encompass all modes of metabolism and scales of abundance. Using a global-scale compilation of ∼35,000 sites and ∼5.6⋅106 species, including the largest ever inventory of high-throughput molecular data and one of the largest compilations of plant and animal community data, we show similar rates of scaling in commonness and rarity across microorganisms and macroscopic plants and animals. We document a universal dominance scaling law that holds across 30 orders of magnitude, an unprecedented expanse that predicts the abundance of dominant ocean bacteria. In combining this scaling law with the lognormal model of biodiversity, we predict that Earth is home to upward of 1 trillion (1012) microbial species. Microbial biodiversity seems greater than ever anticipated yet predictable from the smallest to the largest microbiome.


Related:

ktwop on biodiversity

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.


 

Natural selection is obsolete and the compassionate society needs non-coercive eugenics

March 20, 2016

Natural selection is about being “good enough” and never about excellence. It has been sufficient to the purpose to cope with the slow change of prevailing environment. It has been effective but remarkably inefficient. But now that homo sapiens has developed to the point of influencing – even if not yet controlling – the prevailing environment, the trial and error process of “natural selection” can no longer cope with the pace of change. Compassionate societies take care of their physically unfit and natural selection is effectively bypassed.

Natural selection is about “good enough”, but artificial selection could be about excellence

Natural selection has no direction. In fact it is unintended selection. It just allows for the survival and the reproduction of the “just good enough” individuals (not of the best individuals). “Evolution” is then just the resulting changes in species, where some individuals have had the genetic variation (errors or abnormalities) to be able to survive in a changed environment (habitat and/or competing species). Paradoxically, species which display a wide genetic variation in individuals (large errors), have a greater chance of surviving change. Of course, many abnormal individuals fail to survive, which is the price paid for the survival of the species. In that sense, “natural selection” sacrifices individuals for the sake of the species. The unplanned, unintended “selection” occurs primarily by the deselection of the unfit individuals. You could say it was unethical, since the end (species survival), justifies the means (deselection of unfit individuals). There is no compassion for deselected individuals in natural selection.

Excellence of a particular attribute is never selected for. Survivors are those just good enough, to live long enough, to reproduce. Evolution by this “natural selection” clearly works, but it is not intentional, is not very efficient and can only cope with slow, small changes to the environment. Rapid or large changes cannot be matched by the available genetic variation. When the genetic variation (errors) among individuals does not throw up some which can survive some external change, species go extinct. It is the selection not by a pro-active choice but by whatever is left surviving after a multitude of trials of the errors.

We are getting to the point where we are beginning to be able to discern the genetic components which, partially or wholly, determine health, disease, intelligence and behaviour of the individual. We no longer allow the sick and unintelligent to be deselected. The “compassionate society” has effectively short-circuited the natural selection process which depended on the physically “unfit” dying off. However we take no similar actions about those who are mentally or behaviourally unfit. We have started changing the environment and we have cancelled the death of the physically unfit. But we still allow the mentally or behaviourally unfit to survive and reproduce.

It is time then to also take charge of genetic selection.

We see nothing wrong in genetic intervention in preventing debilitating disease. We even allow capital punishment (abortion) where the genetic fault in a foetus is considered very large. We practice artificial selection – of a sort – with IVF and surrogate motherhood. “Genetic engineering”, and “artificial selection” are nothing but eugenics where no coercion is involved. The Nazi search for “racial purity” involved massive coercion and tried to achieve the goal of a particular physical appearance and external attributes which defined their “master race”.

But without coercion, eugenics is unexceptionable as a method to seek genetic excellence.

Eugenics:The Problem Is Coercion

Razib Khan in The Unz Review

…… the issue with nics is simple: the problem is coercion, and the rest is commentary. I understand that the public is wary and skeptical of CRISPR technology and preimplanation genetic diagnosis. The problem is that the public is also suspicious of food which has DNA in it. Genes are not magic, but that is hard to convince the person on the street. Whereof one does not know, thereof one must be suspicious.

I believe for there to be a clear discussion, one needs to take coercion off the table, and abolish its specter by stating that it just isn’t an option. Then we can have a real dialogue that gets beyond the superficiality induced by the shadow of genocide. For example, consider sentences such as the following from the op-ed above “editing genes for frivolous purposes such as increasing intelligence.” There are many technical reasons that it may not be possible to increase intelligence in the near future through genetic engineering. But would increasing one’s intelligence be frivolous? I don’t think so. Whether you agree with this project or not, it is a serious matter, and gets to the heart of what we value as human beings (or at least some of us). But the specter of genocide casts a pall on exploring these nuanced questions, and that is because of the past record of coercion in eugenics.

Natural selection together with the compassionate society results in an increase in the proportion of “unfit” individuals (physical, mental or behavioural) in the population. But we take no measures to compensate for this by increasing the genetic excellence of succeeding generations.

Natural selection is just not good enough. It can no longer keep up with the pace of change and it is not compatible with a compassionate society. Non-coercive eugenics seeking excellence, not just to compensate for the increasing number of the unfit, but mainly to improve the human condition, is necessary.


 

Related:

Breeding for intelligence?

Is human intelligence declining?


 

Humans have neutralised natural selection and some alternative is needed

December 25, 2015

I was reading the Reuters report about the fatwas issued by ISIS which apparently justify the harvesting of organs of apostates and infidels – even from living individuals – for the sake of transplantation into “good muslims”. There has to be a genetic component to “barbarism”. Then I saw the report of the Pope’s speech at his midnight mass yesterday attacking consumerism and all “bad things”. That got me to thinking that all the pretty speeches made by politicians and Popes, exhorting “good behaviour”, are all meaningless if actions to ensure and sustain “good behaviour” are not also taken. If humans mean that “good behaviour” is something to aspire to and work for, then we must also take the measures available to us which can improve, whatever we may define as “good behaviour”, from one generation to the next. If behaviour is entirely due to nurture then it just requires proper teaching (though the line between teaching and brainwashing is quite thin). But it is not just nurture, of course. There is little doubt, in my mind that there is a significant genetic component to the behaviour that is expressed by an individual.

Certainly there is no doubt that genetics defines the envelope of behaviours that is open to any individual. Normally the envelope of enabled behaviour is so wide that it allows both “good” and “bad” behaviour. Thereafter it may well be nurture and the peculiarities of each individual which determines which particular behaviour will actually be expressed. But the artificial breeding of pets and livestock shows that key behavioural (as opposed to purely physical) characteristics (aggression, curiosity, propensity to cooperate, playfulness, sensitivity, …) can be selected for. Even “intelligence” has been selected for among dogs with some measure of success. It follows that in addition to physical characteristics, the envelope of possible behaviours that can be expressed by an individual can also be altered by genetics. It is highly likely then, that modifying genetics and shifting the envelope will allow certain behaviours to be completely eliminated from the realm of the possible.

Of course it is primarily natural selection which has produced the humans of today and it is this evolution which gives the cognitive behaviour which favours the “compassionate society”. But in this compassionate society, all those who would otherwise have been deselected by natural selection are now protected. The advances of medical science allied with the development of our ethical standards of behaviour (concepts of “human rights”), mean that the physically and mentally disadvantaged are protected and enabled to survive and reproduce. But one consequence is that even those exhibiting “bad behaviour” are also protected and survive to reproduce. The “welfare society” not only protects the weak and disadvantaged, it also ensures that their genetic weaknesses – assuming that they exist – are carried forward into succeeding generations. The “compassionate society” sees to it that even murderous psychopaths (whose behaviour may well be largely due to genetic “faults”), are imprisoned for relatively short times and then permitted (even encouraged) to pass on their faulty genes to succeeding generations.

Something is not right here. To be a compassionate society and protect the weak and disabled is wholly admirable, I think. But when the protection of the weak and disabled extends to the preferential propagation of the weakness or the disability, then the “compassion” also becomes counter-productive and eventually unsustainable. From the perspective of the future survival of the human race, the unnecessary perpetuation of weaknesses and disabilities becomes stupid and suicidal. It may be that the same genes which give some perceived weakness also give some critical survival attribute, in which case there is a trade-off to be made and a call to be taken.

I like the analogy of genetic propagation being seen as a chemical or nuclear reaction. Run-away reactions are avoided if moderation is available. I am coming to the view that some method of moderation of propagation is actually a necessity. Now that natural selection has been neutralised by human compassion and can no longer provide a moderating influence on genetic propagation, then some other form of genetic moderation is needed to avoid “run-away” genetic explosions. That then requires some form of “artificial” selection as the moderator. We may not yet know the specifics and the extent of the genetic components of intelligence or behaviour, but it is a simple conclusion that without moderation, we may well be ensuring the dumbing-down of the human race or ensuring the propagation and expansion of “bad behaviour”. It may not be causal, but there is a clear correlation showing higher fertility rates with lower “intelligence”. It is an arithmetic certainty that, if there is a causal relationship between intelligence and lower birth rates, then the intelligence of humans will decline.

There is nothing fundamentally incompatible between being a compassionate society which protects the weak and the disabled of the current generation, while still ensuring that genetic weaknesses are not carried forward into succeeding generations. In fact, it could even be considered unethical to knowingly allow such weaknesses to be carried forward, especially if we had the knowledge and the means to prevent it. But that, of course, would be considered eugenics.

Darwin’s finches can’t rely on natural selection to survive

December 18, 2015

It is only a mathematical model which predicts that a parasitic fly may drive Darwin’s finches to extinction. And the authors then suggest that human intervention is needed to “save” them because natural selection is just not potent enough or fast enough to allow them to adapt.

That’s all very well, but I feel compelled to speak up for the underdog – which is of course, the parasites. I note that Prof. Dale Clayton displays his prejudices when he says:

“They are maggots basically, is what they are,” said Prof Dale Clayton from the University of Utah, the senior author on the study. ….. “They are pretty nasty customers.”

Why the “specist” discrimination? Why should finches be in a privileged position compared to the flies? Their genes may not be threatened but they surely are more important, as a patently “fitter” species”, than those of the finches?

Another case of misguided conservation, where human intervention is proposed to protect an unfit species at the expense of a fitter species.

EurekAlert: 

Mathematical simulations at the University of Utah show parasitic flies may spell extinction for Darwin’s finches in the Galapagos Islands, but that pest-control efforts might save the birds that helped inspire the theory of evolution.

The new study “shows that the fly has the potential to drive populations of the most common species of Darwin’s finch to extinction in several decades,” says biology professor Dale Clayton, senior author of the study published online Dec. 18 in the Journal of Applied Ecology.

But the research “is not all doom and gloom,” he adds. “Our mathematical model also shows that a modest reduction in the prevalence of the fly – through human intervention and management – would alleviate the extinction risk.”

Mathematical simulations at the University of Utah show parasitic flies may spell extinction for Darwin’s finches in the Galapagos Islands, but that pest-control efforts might save the birds that helped inspire the theory of evolution.

The new study “shows that the fly has the potential to drive populations of the most common species of Darwin’s finch to extinction in several decades,” says biology professor Dale Clayton, senior author of the study published online Dec. 18 in the Journal of Applied Ecology.

But the research “is not all doom and gloom,” he adds. “Our mathematical model also shows that a modest reduction in the prevalence of the fly – through human intervention and management – would alleviate the extinction risk.”

Darwin’s finches image Wikipedia

The authors justify their unjustifiable proposals by invoking the meaningless god of “global diversity”.

The case of the flies and finches exemplifies how “introduced pathogens and other parasites pose a major threat to global diversity,” especially on islands, which tend to have smaller habitat sizes and lower genetic diversity, the researchers write.

It is only another alarmist mathematical model. Yet the fundamental reality, whenever a species goes extinct, is that it no longer has any significant part to play in an ecology. If it was relevant and significant to an ecology then its survival would be implicit. And what makes an ecology containing 10 species any better or any worse than an ecology containing 100 species? Surely it is the effectiveness or sustainability of that ecology which counts and not the number of species it contains.

Craving for junk food is proof that natural selection is obsolete

December 4, 2015
christmas dinner (guardian)

christmas dinner (guardian)

It is that time of the year. There are luscious smells of baking and roasting and frying that assail my poor brain. Almost everything that makes my mouth water is bad for me. I have just about recovered from the frustrations of abstinence from Diwali sweets and Christmas is now already upon us. I have just been soaking the dried fruits in my second best brandy and they can absorb no more. Dark, bitter chocolate and marzipan and glazed cherries are coming out of their hiding places in the larder (and they are hidden to keep me from them). Now I feel schizophrenic. My unconscious brain is delighting in all the good things to come but my conscious, rational brain is just making a list of eating pleasures that will be heavily curtailed or may not even be.

image londonbeep.com

image londonbeep.com

And that got me to wondering why natural selection and evolution could be so horribly, ineffective. How come, I do not crave what is healthy and good for me? If evolution worked properly and worked towards my survival, then surely my brain would crave salads and raw vegetables and fruits and maybe some nuts, but not honey-glazed ham and choux pastry dipped in dark chocolate and filled with cream. Or brandy butter and Christmas cake saturated with booze. Why do I find roast potatoes so much more enticing than plain boiled potatoes (except of course if they were new potatoes and covered in herb butter and melted cheddar)?

My tentative theory is that in the last 2000 years humans have become experts at creating their own, favourable environmental bubbles in which they live. Our bubbles include the production of our food. We live in the Arctic or at the equator and maintain a tropical climate around ourselves throughout the year. Refined sugar and processed meat and hot house vegetables are things that natural selection was not intended to cope with. I read that we crave certain foods to balance the serotonin that our brains desire to maintain a “proper” balance – whatever that might be. Carbohydrates provide serotonin which dispels stress and anxiety. Fats and sugar together produce calm and even euphoria. Before we controlled the production and processing of our foods we only had access to natural sugars through fruits and some vegetables. Meats provided fats. Quantities imbibed were necessarily limited, for sources were not as readily available until after agriculture and animal domestication were established (say from 20,000 to 10,000 years ago for the transition). And there has been another massive step change in the availability of these foods and in their affordability in the last 100 years.

The rate of change with which humans have established the environmental bubbles we create, and in the foods available to us, has been much too fast for natural selection to cope with. Moreover, even though what is bad for us may eventually kill us, medical advances mean that even the “unfit” lovers of bad foods live long enough to reproduce and pass on their genes. Natural selection no longer has a role to play. It has been bypassed and has become irrelevant. Medical care now negates all the deselection of “unfit” individuals that natural selection once eliminated.

I see evolution actually as the result of the individuals who get deselected rather than a proactive selection of those individuals who are just good enough to survive. (It has never been about the survival of the fittest – but only of the selection – by default – of those just fit enough to survive). Hence my conclusion that my cravings for unhealthy foods are the fault of an ineffective and obsolete natural selection.

So as I struggle with (and sometimes give in to) temptations for the next month, I will console myself by blaming the imperfect, lethargic and ineffective natural selection which has failed me.

A comment on the conservation of the Galapagos turtle

November 25, 2015

A reader commented on the About page about an old post where comments are closed.

Galapagos conservation project prevents the evolution of ninja turtles

Archie G Says:

Hello, I wanted to comment on a post but couldn’t find where to do it, so I’ll just do it here. About the Galapagos conservation project. I know your post was intended to be humurous but it think it is important to make this clear anyway: it was not a way to protect a charismatic species above an “ugly” species. Even if rats were there before Darwin arrived, they were an introduced european species (Rattus rattus) that had limited the perpetuation of Galapagos turtles since its introduction to the Island. The rats ate 100% of the hatchlings that had no predators before. It is not “specism”, rodents are not bad, but introduced species in general damage ecosystems, whether they are a pretty animal or not. Conservation is not a matter of some animalistic fan group, it takes years of research and effort to understand its mechanics.

But I beg to differ.

(The Galapagos turtle is itself an invasive species and how it got there is not known. And it is interesting to consider all the humans who were “introduced” to Australia and the New World as invasive species who – for the conservation of the indigenous peoples – should now be rooted out).

“Conservationists” are effectively making value judgements which are unjustified. When “general damage to an ecosystem” is quoted, a judgement has already been made as to which ecosystem is “good” and which is “bad”. But all these judgements always penalise the successful species and protect the unfit species. 

I think the Galapagos turtles are fantastically “charismatic” too, but they are fundamentally an unfit species. In evolutionary terms they are ripe for extinction. So are tigers. But they are being “saved” for the aesthetic sensibilities and the entertainment of humans – not for finding or creating an adapted neo-tiger or neo-turtle species which can find a real place in the world, rather than for surviving in a zoo. Protected reserves – as some of the Galapagos islands are – are little more than large zoos and their purpose is just for the entertainment and edification of humans.

“Conservation” as it is practiced today seeks to maintain a past, or an unviable status quo. Such “conservation” is flawed. In the name of “conservation”, reserves and zoos are used to create big cats for “canned hunting”. By default, a “huntable lion”, no good for anything other than being hunted, is now being bred. Far better to help a species to adapt to real, possible futures. Far better if species were helped (by genetic engineering perhaps) to adjust to the new realities and find a new place. What’s the point of saving a species, that is unfit for a current habitat, and freezing it in this unsuccessful form for a habitat which is no longer viable?

As the dominant species on this planet, humans will never allow some other species to become so successful as to be a threat. There is no moral reason they should. And species which cannot adapt to the dominant species are unfit and deserve to become extinct. After all, 99% of all species that have ever lived are now extinct.

Related:

Genetic adaptation – not stagnating conservation – is the way to help threatened species

Ancient Chinese teeth confirm many and older Out of Africa events

October 15, 2015

Over at 6,000 generations I post about the new paper about the 47 human teeth found in Fuyan Cave, Daoxian, China which are between 80,000 and 120,000 years old.

The 47 human teeth found in Fuyan Cave, Daoxian, China. photo S. XING AND X-J. WU via DiscoveryNews

There were clearly many Out of Africa or Africarabia events starting from 130,000 years ago both before and after the Toba explosion.

80,000-120,000 year old modern humans in S China confirm many and older Out of Africa events

The single Out of Africa event for modern humans is clearly far too simplistic. It is also clear that there were many back to Africa movements as well. Humans expanded sometimes because their old habitats were no longer viable. But, it seems, humans also explored and expanded into new territories from regions of plenty and where they maintained some contact with where they had come from. Probably, just because they could.

Evolutionary story of the giraffe’s long neck does not convince

October 8, 2015

A new paper from the New York Institute of Technology reports on fossil studies of the giraffe’s neck vertebrae which show that (press release):

…. the evolution likely occurred in several stages as one of the animal’s neck vertebrae stretched first toward the head and then toward the tail a few million years later. The study’s authors say the research shows, for the first time, the specifics of the evolutionary transformation in extinct species within the giraffe family. ..

“It’s interesting to note that that the lengthening was not consistent,” said Nikos Solounias, a giraffe anatomy expert and paleontologist at NYIT College of Osteopathic Medicine. “First, only the front portion of the C3 vertebra lengthened in one group of species. The second stage was the elongation of the back portion of the C3 neck vertebra. The modern giraffe is the only species that underwent both stages, which is why it has a remarkably long neck.”

…. “We also found that the most primitive giraffe already started off with a slightly elongated neck,” said Danowitz. “The lengthening started before the giraffe family was even created 16 million years ago.” ….

….. the cranial end of the vertebra stretched initially around 7 million years ago in the species known as Samotherium, an extinct relative of today’s modern giraffe. That was followed by a second stage of elongation on the back or caudal portion around one million years ago. The C3 vertebra of today’s giraffe is nine times longer than its width — about as long as an adult human’s humerus bone, which stretches from the shoulder to the elbow.

Clearly one evolutionary pathway has given us the modern giraffe with its ridiculously long neck, but there was also a pathway which led to the shortening of the neck

As the modern day giraffe’s neck was getting longer, the neck of another member of the giraffe family was shortening. The okapi, found in central Africa, is the only other living member of the giraffe family. Yet, rather than evolving a long neck, Danowitz said this species is one of four with a “secondarily shortened neck,” placing it on a different evolutionary pathway.

But I find the story that the elongation of the giraffes neck was due to natural selection, as a consequence of a survival advantage for longer necked individuals in time of drought, somewhat unsatisfactory. The idea that it was sexual selection at play (a longer neck providing the males with better fighting ability) is even more unsatisfactory.

Let us suppose that a prolonged drought led to all middle size shrubs dying out or at least becoming unavailable to ancestral giraffes through competition. It would have had to have been a very selective drought that allowed only grasses and very low shrubs to survive along with the leaves of taller bushes and trees. We need to remember also that for such a natural selection to work, all the shorter necked giraffes needed to die out and thus be de-selected. It is not impossible that the shorter necked animals were just crowded out by more efficient herbivores which led to the longer necks opening up a niche not available to the other herbivores. But I find the arguments for the extinction of shorter necked giraffes while other herbivores prospered somewhat unconvincing.

The evolutionary pathway to the longer neck is still a mystery.

Why not longer legs? I like this homage to Gary Larson by evolution-outreach.com

Brian Switek reviewed the various theories a few years ago and pointed out

… significant neck elongation began around 14 million years ago during the Late Miocene — after the lineage to which the relatively short-necked okapi split off — and by about 5 million years ago giraffes of modern proportions had evolved. ……..  it appears that the elongation of giraffe necks occurred during a global pattern of aridification in which grasslands replaced forests.

For the moment, the question of “How did the giraffe get its long neck?” must be answered with “We do not yet know”

Switek wrote that five years ago – but it still applies.

We still don’t know.

Genetic mutations among the Inuit demonstrate the reality of “race”

September 23, 2015

It is politically correct to claim that “race” is just an artificial social construct. But of course “race” is real. It is about ancestry and about genetic differences that are quite real. It is about the groupings of peoples exhibiting the same genetic variations. Genetic studies are increasingly confirming the genetic differences that are distinguishable among the many ethnic groups of humans. Genetic groupings exist and are real but they are dynamic, not static. The genetic groupings (colloquially “race”) were different 1,000 generations ago and they will be different again in the future.

A new study shows that

“the Inuit and their Siberian ancestors have special mutations in genes involved in fat metabolism. The mutations help them partly counteract the effects of a diet high in marine mammal fat, mostly from seals and whales that eat fish with high levels of omega-3 polyunsaturated fatty acids.

Those genetic mutations, found in nearly 100 percent of the Inuit, are found in a mere 2 percent of Europeans and 15 percent of Han Chinese, which means that these groups would synthesize omega-3 polyunsaturated fatty acids differently from the Inuit. ….

The mutations seem to be at least 20,000 years old, and may have helped many groups of humans adapt to high-meat, high-fat, hunter-gatherer diets from large land and marine mammals high in certain types of omega-3 and omega-6 fatty acids, ……. They may have arisen among the original Siberians, who have lived in the Arctic for more than 20,000 years and arrived in Greenland when Inuit settled there about 1,000 years ago.”

Matteo Fumagalli et al,  Greenlandic Inuit show genetic signatures of diet and climate adaptation. Science, 18 September 2015 DOI:10.1126/science.aab2319

NewsBerkeley: ……. “The original focus on fish oil and omega-3s came from studies of Inuit. On their traditional diet, rich in fat from marine mammals, Inuit seemed quite healthy with a low incidence of cardiovascular disease, so fish oil must be protective,” said project leader Rasmus Nielsen, a UC Berkeley professor of integrative biology. “We’ve now found that they have unique genetic adaptations to this diet, so you cannot extrapolate from them to other populations. A diet that is healthy for the Inuit may not necessarily be good for the rest of us.”

These genetic mutations in the Inuit have more widespread effects. They lower “bad” LDL cholesterol and fasting insulin levels, presumably protecting against cardiovascular disease and diabetes. They also have a significant effect on height, because growth is in part regulated by a person’s fatty acid profile. The researchers found that the mutations causing shorter height in the Inuit are also associated with shorter height in Europeans.

Seals and walruses were part of the traditional diet of the Inuit, as seen in this illustration of a native village on Canada’s Baffin Island, from the book Arctic Researches and Life Among the Esquimaux (1865) by Charles Francis Hall.

“The mutations we found in the Inuit have profound physiological effects, changing the whole profile of fatty acids in the body, plus it reduces their height by 2 centimeters: nearly an inch,” said Ida Moltke, a University of Copenhagen associate professor of bioinformatics who is joint first author on the study. “Height is controlled by many genes, but this mutation has one of the strongest effects on height ever found by geneticists.”

Nielsen noted that this is some of the clearest evidence to date that human populations are actually adapted to particular diets; that is, they differ in the way they physiologically respond to diets. Just as genome sequencing can lead to personalized medicine tailored to an individual’s specific set of genes, so too may a person’s genome dictate a personalized diet. 

Nielsen and his colleagues at UC Berkeley and in Greenland and Denmark came to their conclusions after analyzing the genomes of 191 Greenlanders with a low admixture of European genes (less than 5 percent) and comparing them to the genomes of 60 Europeans and 44 Han Chinese. They looked for mutations occurring in a large percentage of Inuit individuals but in few or no other groups, which indicates that the mutation spread throughout the Inuit because it was somehow useful to their survival while not essential in other groups.

One cluster of mutations — in genes that code for enzymes that desaturate carbon-carbon bonds in fatty acids — stood out strongly, said Anders Albrechtsen, an associate professor of bioinformatics at the University of Copenhagen and a joint project leader. Fatty acids are the fat in our diet, and occur in saturated, polyunsaturated and unsaturated forms, depending on whether the molecules’ carbon atoms are linked together with no, some or all double bonds. Saturated fats are considered bad because they raise levels of cholesterol in the blood and lower the “good” high-density lipoproteins (HDL), all of which leads to plaque formation and clogged arteries. Diets rich in polyunsaturated and unsaturated fats are linked to lower heart disease. Desaturase enzymes convert dietary fatty acids into fatty acids stored and metabolized by the body.

The mutations common in the Inuit, once known as Eskimos, decrease the production of both omega-3 and omega-6 polyunsaturated fatty acids, presumably to account for the high amount of these fatty acids coming from the diet. Changing production of one fatty acid affects all fatty acids, however, since they regulate one another in a complex way, Albrechtsen said.

Thus, while it’s not clear which specific gene or genes within the cluster is responsible for the alteration in fatty acid metabolism, he said that “when you change the genes that are involved in fatty acid synthesis, you change the whole conversation among fatty acids, and that has a lot of downstream effects.” …… The researchers discovered another common mutation in a gene that is involved in the differentiation of brown, subcutaneous fat cells and brite fat cells, the latter of which generate heat. This may also have helped the Inuit adapt to a cold environment.

Race is real but it is dynamic. The genetically distinguishable race of Inuits goes back about 1,000+ generations. And some other genetic groupings of humans will be observable 1,000 generations on. But those groupings (races) will still be there. As I observed some time ago

We have no difficulty in accepting that different populations (effectively different races in colloquial usage) have differences of physical characteristics due to their genetic ancestry. There is no great outrage now that recent studies point to some genetic differences that Tibetans have which may give them an advantage in absorbing oxygen at high altitudes. Similarly there are no screams when other genetic studies suggest that East Africans (Kenyans and Ethiopians in the main) have some genes – or combination of genes – which give them better endurance and therefore – given good nourishment – lead to better performance as long distance runners. West Africans, or those of West African descent, it seems may have some genetic advantages which make them the fastest sprinters over short distances. African genes also seem to give a lower fat content in body mass – which is genetic – and may be one explanation why their performance as swimmers is less than exceptional. That Indians are more prone to Type 2 diabetes than other “races” is not indignantly opposed but just taken for the observation it is. Indian-Americans (3 generations) are already exhibiting lower rates than their Indian ancestry would indicate. Japanese have very low rates of heart disease but already (in less than 6 generations) Japanese-Hawaiians have heart disease rates that are 2 -3 times higher.

It is illogical to assume that these genetic variations between different geographic populations ( colloquially “races”) have only manifested themselves as physical variations. It is highly probable and probably inevitable that these genetic developments will also have affected the brain, its functioning and behaviour. And intelligence.

If it is acceptable – and not racist – to observe that there are genetic differences in physical characteristics between the “races” of today, then it is just as acceptable and no more racist to observe that there are genetic differences of intelligence between the “races” of today.

The taboo against even discussing genetic groupings (race) and physical and mental characteristics (intelligence) and behaviour is illogical.

There was no biodiversity to begin with

September 15, 2015

I was listening to some conservationists on the radio discussing the rate of loss of species and how this was a catastrophe in the making for biodiversity. It was an unsatisfactory talk mainly because they all made what I thought were quite unjustified assumptions. It was more about political advocacy rather than any attempt to argue based on evidence.

The “politically correct” view is that biodiversity (measured as the number of species in existence) is a “good thing” and that more species is “good” and fewer species is “bad”. Saving endangered species is also a “good” thing. That species are becoming extinct at an alarming rate means catastrophically that a 6th mass extinction is nigh. But I find this viewpoint lacking in substance. We have more species existing today than ever before. Probably too many. Mass extinctions have helped “clean out” the rubbish that evolution throws up. Extinction rates may be high but that is hardly surprising when the number of species is so high. A 6th mass extinction may, in fact, be necessary. More species and more biodiversity is not always a good thing.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

The fossil record shows that biodiversity in the world has been increasing dramatically for 200 million years and is likely to continue. The two mass extinctions in that period (at 201 million and 66 million years ago) slowed the trend only temporarily. Genera are the next taxonomic level up from species and are easier to detect in fossils. The Phanerozoic is the 540-million-year period in which animal life has proliferated. Chart created by and courtesy of University of Chicago paleontologists J. John Sepkoski, Jr. and David M. Raup.

An endangered species is one whose population is low and dangerously in decline. If numbers of individuals of a species are that low, then that species has already become irrelevant in its contribution to the functioning of the biosphere. It may well be a matter of regret, just as there is always regret when a language becomes extinct from disuse. But apart from providing entertainment value for humans, the saving of a few members of a doomed species provides no real benefit for the functioning of the biosphere. I would be very sorry to see tigers becoming extinct, but the reality is that their numbers are so low that they play no significant part in the sustenance of the biosphere. The role of a predator species is primarily to control the population of its prey. From a biodiversity point of view they are already irrelevant. Saving the tiger has nothing to do with maintaining a healthy biodiversity and everything to do with human entertainment (including that of the conservationists) and “feeling good”.

(I am of the opinion that helping an endangered species to survive can be desirable but then “conservation” should be based on helping that species to adapt genetically rather than to freeze it into an artificial habitat – zoos and reserves – to which it is not suited).

At one time there was just a single species that all life derives from – perhaps even just one living cell. (And even for creationists, all the diversity of humankind has derived from a single mating pair – and the raging incest that that implies). There was no biodiversity to begin with. Genetic variation with each generation and genetic mutations then caused new species to come into being, first to fill up the spaces that the prevailing environment allowed and then to adapt to changing environments. If each generation of the first species had bred true there would, of course, be no biodiversity. Genetic variation and empty space in the environment led to growth of species. Overcrowding of a given space or drastic environment change cause the decline and extinction of species. The prevailing level of “biodiversity” at any time is not then some target to be achieved, but just the current balance between the birth and death of species.

It seems almost self-evident to me that, for any given environment there must be an optimum number of species, with particular combinations of characteristics, which allow the ecosystem or biosphere to be in a self-sustaining equilibrium (not growing or declining but self-sustaining). This optimum will vary depending upon the characteristics and interactions between the particular species existing and the available space in the prevailing environment. Then, having fewer than the optimum number of species in that environment would mean that all the complex interdependent, interactions between species that seem to be necessary for sustaining each of the participating species would not be fully developed. I say “seem” because it is not certain that all interdependencies are necessarily of benefit to individual species. “It is the entire ecosystem which benefits” I hear some say, but even that is more an assumption than a conclusion.

But what would happen in such a situation?  If the interactions are truly necessary, then some of these sub-optimal number of species should logically be on the way to stagnation or to extinction. But it is not certain that some new equilibrium will not be reached. One species too few for a given environmental space will only lead to the space being occupied by an existing or a new species. One species too many for a given space will lead to the extinction of a redundant species or of a number of species existing under genetic stress, until genetic variation reduced the stress. The interactions between species in any environment are not planned in advance. They are just those that happen to prevail and survive because they succeed in the environmental space available. Too few species will give an increase of species until overcrowding reduces the number of species. A rapid change of environment and a reduction of the space available must give a decrease in the number of species making up the optimum for a self-sustaining biosphere.

Generally species of plant life have increased in the wake of human habitations.

For example, more than 4,000 plant species introduced into North America during the past 400 years grow naturally here and now constitute nearly 20 percent of the continent’s vascular plant biodiversity.

But then we try to eradicate “invasive” species even though that represents a decrease in biodiversity. Clearly some biodiversity “is not good”. We hunt down successful species as pests when they reach and thrive in new or empty environmental spaces. We protect and support unsuccessful (failed) species in the name of conservation and biodiversity. We have no qualms in trying to eradicate insects, microbes and bacteria which cause human disease even if biodiversity is consequently reduced. From the perspective of the biodiversity of the genetic pool, losing a species of some unknown bacteria may be just as significant as the extinction of the elephant.

The rate of growth of the human species has meant that other species have not been able to adapt fast enough – genetically – to their loss of habitat or the increase of competition. The environmental space available to them has drastically reduced. But that is reality. Creating artificially unsustainable habitats will not change that. The optimum level of biodiversity for the environmental space today is different to that of 100 years ago. Biodiversity cannot be considered independently of the environmental space available. Conservationism which seeks to maintain the wrong level of biodiversity for the available space seems to me to be both futile and stupid. Especially when conservationism has no idea what the “optimum” level of biodiversity is and whether the current level lies above or below the optimum level.

 


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