Archive for the ‘Evolution’ Category

Conservation denies tigers a future as a species

June 13, 2017

There are, it is thought, around 4,000 tigers still living in the “wild”. There may be as many as 8 – 9,000 in captivity (3,000 in China and perhaps 5,000 in the US). The tigers in captivity are in zoos and parks and are, in the US, often bred for “hunting”. Very few (< 100 perhaps) of those in captivity are returned to the “wild” every year. Breeding hybrid tigons and ligers once used to be very popular in zoos but less so now though it is still prevalent for entertainment purposes. The numbers are not very significant.

Tigers are magnificent animals and a cultural icon for humans. No doubt the sabre-toothed tiger was an even more magnificent creature. It is surely a matter of regret that they became extinct a long time ago. As a species they were replaced by others which were more suited to the changing world. If present-day tigers (considered endangered) were to become extinct, it would also be a matter of much regret. But I find the rationale for “conservation” efforts flawed and illogical. The WWF (which is close to being one of my least favourite organisations) writes in a typical woolly-headed, gushing style:

Yet they are more than just a magnificent animal – they are also crucial for the ecosystems in which they live. As top predators of the food chain, tigers keep populations of prey species in check, which in turn maintains the balance between herbivores and the vegetation upon which they feed. Balanced ecosystems are not only important for wildlife, but for people too – both locally, nationally and globally. People rely on forests, whether it is directly for their livelihoods or indirectly for food and products used in our daily lives. ……… Tigers not only protect the forest by maintaining ecological integrity, but also by bringing the highest levels of protection and investment to an area. Tigers are an “umbrella species” – meaning their conservation also conserves many other species in the same area. They are long-ranging and require vast amounts of habitat to survive; an adult male’s home range varies from 150 km2 – 1000 km2.

Tigers are endangered because their habitats are disappearing. That habitat loss is fundamentally irreversible. As a species they already have no significant role to play in the ecosystem prevailing. They have already become a redundant species biologically even if the concept of majestic tigers roaming wild forests still has a massive emotional impact on the selfish human psyche. Creating new tiger reserves – constrained in area by various means –  is little more than creating glorified zoos. They are just parks where the cages are a little bigger.  The tigers themselves are “frozen” into their current, unsuccessful, unsuitable, failed genetic state. They are doomed to continue unchanged and unchanging in a shrinking and ever more unsuitable habitat. There are no natural selection pressures (or artificial selection measures) in play which would make their descendants more capable of surviving in the new habitats due to changes that have already happened and have yet to come. This “conservation” is not about helping the tiger to survive by evolving but is only about freezing them into an increasingly untenable form. It is backwards looking and all about preserving failure.

I am even more convinced that traditional “conservation” is misguided and is done just to satisfy the emotional needs of humans, and not, in any way, forward-looking to help endangered species to adapt and survive into the future.

Fighting against species extinction is to deny evolution   – (ktwop – 2013)

So what then is the objection to – say – tigers becoming extinct which is not just an emotional reaction to the disappearance of a magnificent but anachronistic creature?  The bio-diversity argument is not very convincing and is of little relevance. To artificially keep an unsuccessful species alive in a specially protected environment has no genetic value. It increases the mis-match between the existing environment and the genetic profile needed to survive in that environment. In fact the biodiversity argument is only relevant for “life” in general and never for any particular species or group of species.  It can serve to maintain a very wide range of genetic material in the event of a catastrophe such that some form of life has a chance of continuing. But given a particular environment biodiversity in itself is of little value. …

…. All those species which succeed into the future will be those which continue to “evolve” and have the characteristics necessary to thrive within the world as it is being shaped and changed by the most successful species that ever lived (though we cannot be sure how far some particular species of dinosaur may have advanced). Putting a tiger into a zoo or a “protected” environment actually only preserves the tiger in an “unsuccessful” form in an artificial environment. Does this really count as “saving the species”? We might be of more use to the future of the tiger species if we intentionally bred them to find a new space in a changed world  – perhaps as urban tigers which can co-exist with man.

Smilodon image DinoAnimals.com

I’ll still make a donation to Project Tiger but that is about helping individuals to survive and has nothing to do with saving the species.


Sherpas are genetically more efficient at using Oxygen

May 23, 2017

A new paper today confirms that Sherpas are genetically more efficient at using Oxygen. It is another example of an ethnic group where defining characteristics of the group are genetically inherited.

Horscroft, J et al. Metabolic basis to Sherpa altitude adaptation. PNAS; 22 May 2017; DOI: 10.1073/pnas.1700527114

EurekAlertSherpas have evolved to become superhuman mountain climbers, extremely efficient at producing the energy to power their bodies even when oxygen is scarce, suggests new research published today in the Proceedings of the National Academy of Sciences (PNAS). …..

When oxygen is scarce, the body is forced to work harder to ensure that the brain and muscles receive enough of this essential nutrient. One of the most commonly observed ways the body has of compensating for a lack of oxygen is to produce more red blood cells, which are responsible for carrying blood around the body to our organs. This makes the blood thicker, however, so it flows more slowly and is more likely to clog up blood vessels.

Mountain climbers are often exposed to low levels of oxygen, particularly at high altitudes. This is why they often have to take time during long ascents to acclimatise to their surroundings, giving the body enough time to adapt itself and prevent altitude sickness. In addition, they may take oxygen supplies to supplement the thin air.

Scientists have known for some time that people have different responses to high altitudes. While most climbers require additional oxygen to scale Mount Everest, whose peak is 8,848m above sea level, a handful of climbers have managed to do so without. Most notably, Sherpas, an ethnic group from the mountain regions of Nepal, are able to live at high altitude with no apparent consequences to their health – as a result, many act as guides to support expeditions in the Himalayas, and two Sherpas are known to have reached the summit of Everest an incredible 21 times.

Previous studies have suggested differences between Sherpas and people living in non-high altitude areas, known collectively as ‘lowlanders’, including fewer red blood cells in Sherpas at altitude, but higher levels of nitric oxide, a chemical that opens up blood vessels and keeps blood flowing.

Evidence suggests that the first humans were present on the Tibetan Plateau around 30,000 years ago, with the first permanent settlers appearing between 6,000-9,000 years ago. This raises the possibility that they have evolved to adapt to the extreme environment. This is supported by recent DNA studies, which have found clear genetic differences between Sherpa and Tibetan populations on the one hand and lowlanders on the other. Some of these differences were in their mitochondrial DNA – the genetic code that programmes mitochondria, the body’s ‘batteries’ that generate our energy.

To understand the biological differences between the Sherpas and lowlanders, a team of researchers led by scientists at the University of Cambridge followed two groups as they made a gradual ascent up to Everest Base Camp at an elevation of 5,300m.

The study was part of Xtreme Everest, a project that aims to improve outcomes for people who become critically ill by understanding how our bodies respond to the extreme altitude on the world’s highest mountain. This year marks 10 years since the group’s first expedition to Everest.

The lowlanders group comprised 10 investigators selected to operate the Everest Base Camp laboratory, where the mitochondrial studies were carried out by James Horscroft and Aleks Kotwica, two PhD students at the University of Cambridge. They took samples, including blood and muscle biopsies, in London to give a baseline measurement, then again when they first arrived at Base Camp and a third time after two months at Base Camp. These samples were compared with those taken from 15 Sherpas, all of whom were living in relatively low-lying areas, rather than being the ‘elite’ high altitude climbers. The Sherpas’ baseline measurements were taken at Kathmandu, Nepal.

The researchers found that even at baseline, the Sherpas’ mitochondria were more efficient at using oxygen to produce ATP, the energy that powers our bodies.

As predicted from genetic differences, they also found lower levels of fat oxidation in the Sherpas. Muscles have two ways to get energy – from sugars, such as glucose, or from burning fat (fat oxidation). The majority of the time we get our energy from the latter source; however, this is inefficient, so at times of physical stress, such as when exercising, we take our energy from sugars. The low levels of fat oxidation again suggest that the Sherpas are more efficient at generating energy.

The measurements taken at altitude rarely changed from the baseline measurement in the Sherpas, suggesting that they were born with such differences. However, for lowlanders, measurements tended to change after time spent at altitude, suggesting that their bodies were acclimatising and beginning to mimic the Sherpas’.

One of the key differences, however, was in phosphocreatine levels. Phosphocreatine is an energy reserve that acts as a buffer to help muscles contract when no ATP is present. In lowlanders, after two months at high altitude, phosphocreatine levels crash, whereas in Sherpas levels actually increase.

In addition, the team found that while levels of free radicals increase rapidly at high altitude, at least initially, levels in Sherpas are very low. Free radicals are molecules created by a lack of oxygen that can be potentially damaging to cells and tissue.

“Sherpas have spent thousands of years living at high altitudes, so it should be unsurprising that they have adapted to become more efficient at using oxygen and generating energy,” says Dr Andrew Murray from the University of Cambridge, the study’s senior author. “When those of us from lower-lying countries spend time at high altitude, our bodies adapt to some extent to become more ‘Sherpa-like’, but we are no match for their efficiency.” ……

Race is not a social construct as the politically correct would have me believe. Race is real and is a consequence of ancestry. Racial classification is fluid and changes but only over generational time. Sherpa genes help high-altitude living. There are West African genes which help sprinters, East African genes which are beneficial for long-distance runners, Scandinavian genes which predispose to diabetes 1 and Indian genes which predispose to diabetes 2.

And there are genes which predispose to high performance in IQ testing.


 

Fantasy or just bad science — “humans in North America 130,000 years ago”

April 27, 2017

Nothing wrong with fantasy of course. It just makes for bad science. The real problem here is that it is very bad science being encouraged by the journal Nature. The whole paper is based on analysing some crushed Mastodon bones which were found 25 years ago, a doubtful application of a dating technique and then the assertion that it was impossible for the bones to have been crushed by anything other than human activity. They made some experiments to crush bones and then they leap to their fantastic conclusion that the crushing was (was and not might have been) by stone tools (of which there are no traces) made by unknown humans (who also have left no other trace).

This is not just fantasy. It is borderline rubbish.

Controversial study claims humans reached Americas 100,000 years earlier than thought

The “science” is quite sophisticated —–

“Scientific” bone crushing

Even the staid BBC is driven to report:

Prof Michael R Waters, from Texas A&M University in College Station, described the new paper as “provocative”. He told BBC News the study “purports to provide evidence of human occupation of the Americas some 115,000 years before the earliest well established evidence”.

Prof Waters explained: “I have no issues with the geological information – although I would like to know more about the broader geological context – and the likely age of the locality. However, I am sceptical of the evidence presented that humans interacted with the mastodon at the Cerutti Mastodon site.  …… To demonstrate such early occupation of the Americas requires the presence of unequivocal stone artefacts. There are no unequivocal stone tools associated with the bones… this site is likely just an interesting paleontological locality.”

Prof Tom Dillehay, from Vanderbilt University in Nashville, Tennessee, told BBC News the claim was not plausible. Another authority on early American archaeology, Prof David Meltzer from Southern Methodist University in Dallas, Texas, said: “Nature is mischievous and can break bones and modify stones in a myriad of ways. ……. With evidence as inherently ambiguous as the broken bones and non-descript broken stones described in the paper, it is not enough to demonstrate they could have been broken/modified by humans; one has to demonstrate they could not have been broken by nature. ….. This is an equifinality problem: multiple processes can cause the same product.”


 

Democracy, like natural selection, has no need for excellence

April 14, 2017

Natural selection gives traits that are good enough for survival up to the time of reproduction. There is no value to be gained by being anything beyond just good enough to survive and only till reproduction is accomplished. Natural selection is about being “good enough” and there is no force which drives towards excellence. Fast enough may, in fact, be much more successful for descendants than fastest. Strong enough is good enough and there is no advantage necessarily accruing from being the strongest. The forces of natural selection are quite satisfied with intelligent enough and do not persist towards increasing intelligence. The equilibrium position is mediocrity.

And so it is with democracies. Democracies are all about winning elections, not about selection of the “best” leaders. A winning candidate only needs to be sufficiently intelligent and sufficiently competent and sufficiently rich and  sufficiently cunning and sufficiently dishonest to ensure the capture of sufficient votes. There is no value, and there may well be a negative value, in having more of a vote-winning attribute than just necessary.

Given that excellence, of any attribute, must be a minority “thing” (the bell curve again), any system promoting the majority must inevitably promote a leveling down – a chase for mediocrity. Natural selection is all about increasing population. Extinction is failure and increasing population is the measure of success. Democracies pander to the majority in a population. There will always be more of the poor than of the rich, the unintelligent will always outnumber the intelligent and the incompetent will always swamp the competent.

Excellence in sport requires special coaching and training regimes for elite squads of young athletes. Academic excellence requires elite academic institutions. Excellence in science needs its ivory towers. Excellence in companies is achieved by autocracies (including monarchies) but never by democracies. Military excellence requires elite troops.  Excellence in government and in management requires autocrats. To achieve excellence in almost any field requires elitism. “Socialist principles” abhor elitism. It is not perhaps so surprising that the essence of “social democrats” lies in leveling down, in making a god out of mediocrity.

At some point humans and human societies will find the need to drive towards improvement and a search for excellence. With no pressure to increase population humans will be freed from the constraints of natural selection and will be able to target excellence. Natural selection will have to be given direction with a strong dose of artificial selection. Once poverty is eliminated (but not the poor who must always be there) and population is stable or declining, even human societies will be freed to chase excellence. Democracies will then need to acquire some spine by institutionalising  more than just a little whiff of autocracy. Voters and candidates for election will need to qualify, votes will be weighted and elected leaders will be autocrats for their terms of office.

Leaders might then begin to lead again rather than being followers of the mob.


 

Does life start when the egg is laid?

April 9, 2017

Birds and reptiles (and the duck billed platypus which is a mammal), lay eggs for their offspring. Their only interaction of the parents with the egg after it is laid is to keep predators away and to incubate it – which is often done by the male. The development of the embryo in the egg requires no nourishment or any biological intervention from the parents.

In the case of a chicken’s development, the egg when laid consists of a minuscule embryo (0.0002 grams) and nutrients. The chick hatches when the nutrients have been consumed and its weight has increased to about 30-31 grams.

Image result for development of a chicken egg

from EnchantedLearning.com

Is the chick alive when the egg is laid?

One could argue that the embryo at that point is not yet deserving of the label “chick”. But I think there is no rational way in which to question that “life” has definitely started by the time the fertilised egg is laid. In the case of humans a fertilised egg is called a “zygote” until it has implanted itself (about 6 -10 days after conception) in the wall of the womb. It is then called an “embryo”. It is called a “fetus” only from 8 weeks after conception and remains a “fetus” till the birth of a “child”. Just as a “chick” only emerges after egg hatching, a human “child” only emerges after birth. But in both cases life, life has begun much earlier. By the time a hen lays an egg, the genetic identity of the embryo in the egg has already been fixed. The unique genetic identity whether for chicken or for human is actually fixed when conception occurs. The implantation of a human zygote in the wall of the womb is the corresponding point when an embryo is defined. The genetic identity of the embryo has then been well established and the life of a unique identity has clearly begun.

An individual human time line is then not so complicated as the Great Abortion Debate would make it to be:

0: Conception: Genetic identity is established. Life begins as a zygote.

+2: Implantation in the womb: Life continues as an embryo.

+8: Life continues as a fetus

+40: Life continues as a child.

+1340: Child becomes adult when brain development is complete

+4720 (approximately): Life of that unique identity ends


The time when a unique identity is established and life begins is quite simply defined and the Great Abortion Debate is actually about the ethics of terminating that life at different times during its existence. It is trying to make an ethical distinction between breaking an egg for a breakfast omelette or killing a chicken for a roast dinner. (But note also that many vegetarians eat eggs but a chicken eater is never considered a vegetarian). Abortion, infanticide, murder or euthanasia are just labels for different times at which life is to be terminated. Abortion always kills a fetus (not a child) and infanticide always kills a child (not a fetus). But whether it is a zygote which fails to implant itself, or a fetus which is aborted, or a child killed for being the wrong gender, or an aged person being assisted to die, it is the same life, the same identity, which is terminated.

And, I note, ethics are always personal and cannot be imposed by a society on someone. But a society can always exclude someone from the club for not complying with its ethical code.

This Slate article unnecessarily complicates the matter only to try and justify a particular ethical view.

When Does Life Begin? It’s Not So Simple

It actually is just that simple. A unique genetic identity and life are established with conception.


 

Inheritance rules

March 8, 2017

Genes surely define the behavioural envelope within which an individual can operate. This envelope, though, is quite wide. Nevertheless, one would think that after some 10,000 generations of evolution as anatomically modern humans, living in societies where cooperation is primal, that all those beneficial behavioural traits which had a genetic component, would have by now been selected. But psychopaths are not extinct, anti-social behaviour is very common and compassion is not a survival trait to be selected for. Barbarism has not been deselected by evolution. It could be that the same genes which give religious fanaticism also give rise to artistic creativity.

One would also have expected that the intelligence we credit humans with, and see as a key differentiating factor from other creatures, would also have been selected as a trait. Of course intelligence is not so easily defined and it certainly is not just the result of an IQ test. There are suggestions, from brain size measurements, that intelligence, as given by brain size, peaked when we were still hunter gatherers, possibly because that was when individuals needed to be very autonomous and – by inference – quite selfish to survive.  IQ tests today are not a good predictor of the success of an individual in society, probably because the test does not capture those aspects of intelligence that have to do with leadership, team work or entrepreneurial ability.

There was a time when light and dark were outside human control. So far we have left evolution to take its slow, natural, wasteful, trial and error course. But the speed of natural selection is now completely out of sync with the speed of change. The few attempts to guide evolution have been discredited by the manner in which they have been applied. They have been based on the principles we have used to breed livestock and dogs by terminating unwanted characteristics and only allowing individuals with desired characteristics to have progeny. The Nazi experiments with eugenics and even Margaret Sanger’s objectives of controlling the black population in the US (by making abortions freely available) were horrible (still are in some instances), in their manner of execution. But the idea of guiding our own evolution is still sound and an idea whose time has still to come. We are already tinkering with eugenics – though in a very amateurish way – when foetuses are aborted, or IVF is used, or when sperm banks are drawn upon, or fertility drugs or surrogacy are employed. Now, we have a sort of eugenics by default. When foetuses are screened genetically as a matter of course, and when genetic manipulation and correction becomes possible then eugenics will have properly arrived.


 

3rd great “mass extinction” was due to an ice age and not to global warming

March 8, 2017

A new paper addresses the drivers behind the 3rd great “mass extinction” around 250 million years ago. It finds that it was due to an ice age and not due to global warming as many have speculated.

Björn Baresel, Hugo Bucher, Borhan Bagherpour, Morgane Brosse, Kuang Guodun, Urs Schaltegger. Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms. Scientific Reports, 2017; 7: 43630 DOI: 10.1038/srep43630

Universite de Geneve Press Release:

The Earth has known several mass extinctions over the course of its history. One of the most important happened at the Permian-Triassic boundary 250 million years ago. Over 95% of marine species disappeared and, up until now, scientists have linked this extinction to a significant rise in Earth temperatures. But researchers from the University of Geneva (UNIGE), Switzerland, working alongside the University of Zurich, discovered that this extinction took place during a short ice age which preceded the global climate warming. It’s the first time that the various stages of a mass extinction have been accurately understood and that scientists have been able to assess the major role played by volcanic explosions in these climate processes. This research, which can be read in Scientific Reports, completely calls into question the scientific theories regarding these phenomena, founded on the increase of CO2 in the atmosphere, and paves the way for a new vision of the Earth’s climate history. 

Teams of researchers led by Professor Urs Schaltegger from the Department of Earth and Environmental Sciences at the Faculty of Science of the UNIGE and by Hugo Bucher, from the University of Zürich, have been working on absolute dating for many years. They work on determining the age of minerals in volcanic ash, which establishes a precise and detailed chronology of the earth’s climate evolution. They became interested in the Permian-Triassic boundary, 250 million years ago, during which one of the greatest mass extinctions ever took place, responsible for the loss of 95% of marine species. How did this happen? for how long marine biodiversity stayed at very low levels? 

Researchers worked on sediment layers in the Nanpanjiang basin in southern China. They have the particularity of being extremely well preserved, which allowed for an accurate study of the biodiversity and the climate history of the Permian and the Triassic. “We made several cross-sections of hundreds of metres of basin sediments and we determined the exact positions of ash beds contained in these marine sediments,” explained Björn Baresel, first author of the study. They then applied a precise dating technique based on natural radioactive decay of uranium, as Urs Schaltegger added: “In the sedimentary cross-sections, we found layers of volcanic ash containing the mineral zircon which incorporates uranium. It has the specificity of decaying into lead over time at a well-known speed. This is why, by measuring the concentrations of uranium and lead, it was possible for us to date a sediment layer to an accuracy of 35,000 years, which is already fairly precise for periods over 250 million years.”
Ice is responsible for mass extinction

By dating the various sediment layers, researchers realised that the mass extinction of the Permian-Triassic boundary is represented by a gap in sedimentation, which corresponds to a period when the sea-water level decreased. The only explanation to this phenomenon is that there was ice, which stored water, and that this ice age which lasted 80,000 years was sufficient to eliminate much of marine life. Scientists from the UNIGE explain the global temperature drop by a stratospheric injection of large amounts of sulphur dioxide reducing the intensity of solar radiation reaching the surface of the earth. “We therefore have proof that the species disappeared during an ice age caused by the activity of the first volcanism in the Siberian Traps,” added Urs Schaltegger. This ice age was followed by the formation of limestone deposits through bacteria, marking the return of life on Earth at more moderate temperatures. The period of intense climate warming, related to the emplacement of large amounts of basalt of the Siberian Traps and which we previously thought was responsible for the extinction of marine species, in fact happened 500,000 years after the Permian-Triassic boundary.

This study therefore shows that climate warming is not the only explanation of global ecological disasters in the past on Earth: it is important to continue analysing ancient marine sediments to gain a deeper understanding of the earth’s climate system.

We now have more living species than ever before. The number of “garbage” species is very high and a new “mass extinction” (the sixth) is needed to clear out the rubbish. A Herculean task and hopefully humans will not be one of the “garbage” species. When it comes it is more likely to be due to a global cooling than a global warming.

There are thought to have been 5 great “mass extinctions” in the past. A “mass extinction” removes around 30 – 50% of extent species and can be seen as a self-correcting method for getting rid of the detritus remaining from failed evolution.

But I would argue instead that mass extinctions are necessary and unavoidable. They are necessitated by the ineffectiveness of the process of evolution itself. They provide the self-correction necessary to cope with the mass of “rubbish” species created by the hit-and-miss process of evolution. The external shock is only incidental and acts as the trigger for the extinction of the highly-stressed “rubbish” species. None of the historical mass extinctions ever posed any threat to the continuation of life. Instead they have served to muck out the dung from the evolutionary stables.

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.

The clue lies here:

Wikipedia: Although there are 10–14 million species of life currently on the Earth, more than 99 percent of all species that ever lived on the planet are estimated to be extinct.

Evolution fails in over 99% of its attempts to create species that can survive. The 1%  of species that do and have survived may seem to be perfectly tailored for the prevailing conditions but that is putting the cart before the horse. Evolution has no direction and does not seek excellence. It only throws up a plethora of species where just 1% of those species happen to suit the prevailing conditions. One round peg out of a 100 different shapes may happen to fit a round hole but the round peg itself was not designed to fit – it happened to be the only one of many which did. For every species which is just good enough to survive, evolution gives another 99 which are not. As a process it is a remarkably ineffective one. Humans are not the result of “intelligent design”. They are just the 1% of all the species created by evolution which happened to fit the round hole of the prevailing environment.


 

Dinosaurs died a cold, dark and miserable death

February 3, 2017

If dinosaurs had not died out, there would not have been the room in the ecosystem for the evolution of the primates (and many other species and perhaps including most birds). Dinosaurs roamed the earth from about 200+ million years ago until about 65 mya. Some mammals did overlap with the dinosaurs but mammal evolution really took off only after the dinosaurs mad way for them  The earliest history of primate-like mammals can be traced back to about 65 mya. So, for humans, the extinction of the dinosaurs was existential.

A simulation study from the Potsdam Institute for Climate Impact Research (PIK who, it should be noted, are most famous for exaggerations of sea-rise in their climate models) concludes that it was an asteroid impact and not a volcanic eruption that caused the dinosaur extinction. (I always take “science” from Potsdam with a large pinch of salt since they often could be called the Potsdam Institute for Global Warming Worship).

Brugger, J., Feulner, G., Petri, S. (2017): Baby, it’s cold outside: Climate model simulations of the effects of the asteroid impact at the end of the Cretaceous. Geophysical Research Letters [DOI:10.1002/2016GL072241]

Abstract

Sixty-six million years ago, the end-Cretaceous mass extinction ended the reign of the dinosaurs. Flood basalt eruptions and an asteroid impact are widely discussed causes, yet their contributions remain debated. Modeling the environmental changes after the Chicxulub impact can shed light on this question. Existing studies, however, focused on the effect of dust or used one-dimensional, noncoupled atmosphere models. Here we explore the longer-lasting cooling due to sulfate aerosols using a coupled climate model. Depending on aerosol stratospheric residence time, global annual mean surface air temperature decreased by at least 26°C, with 3 to 16 years subfreezing temperatures and a recovery time larger than 30 years. The surface cooling triggered vigorous ocean mixing which could have resulted in a plankton bloom due to upwelling of nutrients. These dramatic environmental changes suggest a pivotal role of the impact in the end-Cretaceous extinction.

Potsdam has put out a press release:

How the darkness and the cold killed the dinosaurs

66 million years ago, the sudden extinction of the dinosaurs started the ascent of the mammals, ultimately resulting in humankind’s reign on Earth. Climate scientists now reconstructed how tiny droplets of sulfuric acid formed high up in the air after the well-known impact of a large asteroid and blocking the sunlight for several years, had a profound influence on life on Earth. Plants died, and death spread through the food web. Previous theories focused on the shorter-lived dust ejected by the impact. The new computer simulations show that the droplets resulted in long-lasting cooling, a likely contributor to the death of land-living dinosaurs. An additional kill mechanism might have been a vigorous mixing of the oceans, caused by the surface cooling, severely disturbing marine ecosystems.

“The big chill following the impact of the asteroid that formed the Chicxulub crater in Mexico is a turning point in Earth history,” says Julia Brugger from the Potsdam Institute for Climate Impact Research (PIK), lead author of the study to be published today in the Geophysical Research Letters. “We can now contribute new insights for understanding the much debated ultimate cause for the demise of the dinosaurs at the end of the Cretaceous era.” To investigate the phenomenon, the scientists for the first time used a specific kind of computer simulation normally applied in different contexts, a climate model coupling atmosphere, ocean and sea ice. They build on research showing that sulfur- bearing gases that evaporated from the violent asteroid impact on our planet’s surface were the main factor for blocking the sunlight and cooling down Earth.

In the tropics, annual mean temperature fell from 27 to 5 degrees Celsius

“It became cold, I mean, really cold,” says Brugger. Global annual mean surface air temperature dropped by at least 26 degrees Celsius. The dinosaurs were used to living in a lush climate. After the asteroid’s impact, the annual average temperature was below freezing point for about 3 years. Evidently, the ice caps expanded. Even in the tropics, annual mean temperatures went from 27 degrees to mere 5 degrees. “The long-term cooling caused by the sulfate aerosols was much more important for the mass extinction than the dust that stays in the atmosphere for only a relatively short time. It was also more important than local events like the extreme heat close to the impact, wildfires or tsunamis,” says co-author Georg Feulner who leads the research team at PIK. It took the climate about 30 years to recover, the scientists found.

In addition to this, ocean circulation became disturbed. Surface waters cooled down, thereby becoming denser and hence heavier. While these cooler water masses sank into the depths, warmer water from deeper ocean layers rose to the surface, carrying nutrients that likely led to massive blooms of algae, the scientists argue. It is conceivable that these algal blooms produced toxic substances, further affecting life at the coasts. Yet in any case, marine ecosystems were severely shaken up, and this likely contributed to the extinction of species in the oceans, like the ammonites.

“It illustrates how important the climate is for all lifeforms on our planet”

The dinosaurs, until then the masters of the Earth, made space for the rise of the mammals, and eventually humankind. The study of Earth’s past also shows that efforts to study future threats by asteroids have more than just academic interest. “It is fascinating to see how evolution is partly driven by an accident like an asteroid’s impact – mass extinctions show that life on Earth is vulnerable,” says Feulner. “It also illustrates how important the climate is for all lifeforms on our planet. Ironically today, the most immediate threat is not from natural cooling but from human-made global warming.”

Of course the last few lines of the press release are added for political correctness.

One hopes that the simulations used here are not as bad as those used for sea-rise modelling (where they tend to modify and use models so as to give their desired, pre-determined results).


 

Control of fire was more recent than 1.2 million years ago (but it was still the start of the anthropocene)

December 16, 2016

A new paper analysing dental plaque from a hominin molar suggests that this group did not use fire for cooking, but had a balanced diet of raw meat and plants. The molar is one of the earliest hominin fragments found in Europe and is thought to be 1.2 million years old. Of course they may have had some rudimentary control of fire which did not extend, till then, to cooking.

Hardy, K., Radini, A., Buckley, S. et al. Sci Nat (2017) 104: 2. doi:10.1007/s00114-016-1420-x, Diet and environment 1.2 million years ago revealed through analysis of dental calculus from Europe’s oldest hominin at Sima del Elefante, Spain

Abstract: Sima del Elefante, Atapuerca, Spain contains one of the earliest hominin fragments yet known in Europe, dating to 1.2 Ma. Dental calculus from a hominin molar was removed, degraded and analysed to recover entrapped remains. Evidence for plant use at this time is very limited and this study has revealed the earliest direct evidence for foods consumed in the genus Homo. This comprises starchy carbohydrates from two plants, including a species of grass from the Triticeae or Bromideae tribe, meat and plant fibres. All food was eaten raw, and there is no evidence for processing of the starch granules which are intact and undamaged. Additional biographical detail includes fragments of non-edible wood found adjacent to an interproximal groove suggesting oral hygiene activities, while plant fibres may be linked to raw material processing. Environmental evidence comprises spores, insect fragments and conifer pollen grains which are consistent with a forested environment.

The control of fire is thought to have been achieved between 1.5 million and 400,000 years ago and coinciding with the evolution of homo habilis to homo erectus. This research suggests that , at least in Europe, cooking had not been established by 1.2 million years ago. But whether the particular individual whose molar has been studies was a homo erectus or an evolving homo habilis is unknown.

homo-timeline

from Pinterest

The intriguing question, of course, is whether human evolution led to control of fire or whether the control of fire led to the evolution of homo sapiens from homo erectus. The archaeological evidence is that control of fire was certainly established by about 800,000 years ago and that hearths (specifically for cooking) were known some 400,000 years ago. This research is consistent with the eating of cooked meat not having begun by 1.2 million years ago. Probably this was not widespread till about 400,000 years ago.

I find it most plausible that the control of fire was the single critical development/advance which made the evolution to homo sapiens possible and which made human social and technological development inevitable. It also seems more than just plausible that the real increase in brain size was connected to cooking and the increase of energy available to the human physique by a diet based on cooking meat. It was the control of fire which was the true start of the anthropocene:

The advent and control of fire led – eventually but inevitably –  to the Stone Age transforming into the Bronze Age and the Iron Age. And in due course it has given the Machine Age, the Electrical Age, the Plastics Age and the current Semiconductors Age. All these “Ages” are surely part of the Anthropocene. There is a case to be made for the advent of stone tools defining Man but I think there is a much stronger case to be made for the advent and control of fire being what defines and distinguishes “Man” from all other animals.

Once fire was harnessed, the dominance of Homo Sapiens not just over other species but also over the environment became inevitable. Fire saw humans through the Ice Ages. The Stone Age plus fire gave the Bronze Age. The Bronze Age + fire led to the Iron Age. It was fire in its various avatars (hearths to ovens to smelters, or energy to steam to electricity) which helped transform one Age to the next.

The one single capability which initiated the divergence of humans from all other animals and which has resulted in the inevitable development and domination of modern humans is the control of fire. And that was around 400,000 years ago. The Age of Man began when Homo Erectus learned to produce fire at will and to contain fire in a hearth. I would even speculate that without fire Homo Erectus would not have survived to evolve into Homo Sapiens. Without fire Homo Sapiens would not have thrived through the ice ages or left the tropics to colonise more northern climes.


 

Homo inferieur

June 24, 2016

Homo sapiens include Homo denisova,  Homo neanderthalensis, another unknown race now extinct and Anatomically Modern Humans (Homo sapiens sapiens).

Future evolution will probably show up as a Homo superieur in about 10,000 generations. Along the way we will also see a degeneration of some to be Homo inferieur.

High on my list of of those making up Homo inferieur will be the participants of some of the “reality TV shows” which make me cringe.

This picture is from the Daily Mail.

Humans rutting in a zoo for the viewing entertainment of others.

All it needs is a hushed David Attenborough commenting on the behaviour of these degenerate samples of Homo inferieur.

Homo inferieur


 


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