Ice and organic chemicals found on an asteroid back the theory that asteroids provided the Earth with the bare necessities of life

Astronomers have detected a coating of ice and organic chemicals on one of the largest asteroids in the solar system.

From the Guardian

The space rock, called 24 Themis, is roughly the size of Sicily and orbits the sun in the main belt of asteroids between Mars and Jupiter, more than 300 million kilometres from Earth.

Asteroid 24 Themis and two small fragments resulting from an impact more than 1bn years ago. Scientists were surprised to find ice and organic chemicals on the asteroid’s surface. Artist’s impression: Gabriel Pérez/Servicio MultiMedia

The discovery supports the idea that asteroids may have brought plentiful supplies of water and organic material to Earth in the distant past and so set the stage for the emergence of life.

Two independent groups confirmed the composition of the asteroid’s surface after observing the 200km-wide rock using Nasa’s Infrared Telescope Facility (IRTF) which sits on the summit of Mauna Kea in Hawaii.

Analysis of infrared light glinting off the surface of the asteroid revealed that some wavelengths were being absorbed by water molecules. Further investigation suggested complex organic molecules were also present. The findings are reported in two papers in the journal Nature.

“The organics we detected appear to be complex, long-chained molecules,” said Josh Emery, a planetary scientist at the University of Tennessee and lead author on one of the studies. “Raining down on a barren Earth in meteorites, these could have given a big kickstart to the development of life.”

The discovery of frozen water on the asteroid has surprised some scientists because the sun warms the surface enough for ice to melt. One possible explanation is that ice in the core of the asteroid is heated into water vapour, which seeps through pores in the rock and freezes temporarily when it reaches the surface.

In the second study, a team led by Humberto Campins at the University of Central Florida timed its observations to take account of the asteroid’s rotation every eight hours and produce a crude map of the surface. It shows that the entire surface of the asteroid is coated with a layer of frost no more than one ten-thousandth of a millimetre thick.

In an accompanying article, Henry Hsieh, a planetary scientist at Queens University in Belfast, likened the ice to a “living fossil”: a remnant of the solar system that many considered long gone.

“This is a thin layer of ice. It’s not like going outside on a snowy day,” he told the Guardian. “But we didn’t really think water would survive in the asteroid belt, and certainly not on the surface of an asteroid.”

The discovery is intriguing because it may finally explain how two thirds of the Earth came to be submerged in water, turning a parched rock into a haven for life.

The Earth formed close to the sun as a dry boulder 4.5bn years ago, but asteroids from cooler regions of space would have slammed into the surface for millennia, releasing any water they contained on impact. At the time, asteroids were more numerous and may have carried far more water than has been found on 24 Themis.

Some scientists believe asteroids may have delivered water to every planet in the solar system, but Earth’s rocky surface, size and orbit ensured water condensed and remained on the ground, ultimately forming vast seas and oceans.

“Each asteroid might not have carried a lot of water, but if you strike a planet with a few thousand or million of them, it would gradually build up,” Hsieh said.

The finding of frozen water as far out as the main asteroid belt suggests water might also be spread throughout alien solar systems. “The building blocks of life – water and organics – may be more common near each star’s habitable zone,” said Emery. “The coming years will be truly exciting as astronomers search to discover whether these building blocks of life have worked their magic there as well.”

It has long been a fascinating puzzle to scientists: Why did our apelike ancestors come down from the trees and develop brains many times larger than they actually needed? Many theories have been discussed, most of which revolve around social cooperation; big brains would have helped our ancestors develop language, make better tools, plan hunting strategies, and pass on complex culture to the next generation.

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From the Guardian, by Cian O’Luanaigh

A gene that controls red blood cell production evolved quickly to enable Tibetans to tolerate high altitudes, a study suggests. The finding could lead researchers to new genes controlling oxygen metabolism in the body.

An international team of researchers compared the DNA of 50 Tibetans with that of 40 Han Chinese and found 34 mutations that have become more common in Tibetans in the 2,750 years since the populations split. More than half of these changes are related to oxygen metabolism.

The researchers looked at specific genes responsible for high-altitude adaptation in Tibetans. “By identifying genes with mutations that are very common in Tibetans, but very rare in lowland populations we can identify genes that have been under natural selection in the Tibetan population,” said Professor Nielsen. “We found a list of 20 genes showing evidence for selection in Tibet – but one stood out: EPAS1.”

The gene, which codes for a protein involved in responding to falling oxygen levels and is associated with improved athletic performance in endurance athletes, seems to be the key to Tibetan adaptation to life at high altitude. A mutation in the gene that is thought to affect red blood cell production was present in only 9% of the Han population, but was found in 87% of the Tibetan population.

“It is the fastest change in the frequency of a mutation described in humans,” said Professor Rasmus Nielsen of the University of California Berkeley, who took part in the study.

There is 40% less oxygen in the air on the 4,000m high Tibetan plateau than at sea level. Under these conditions, people accustomed to living below 2,000m – including most Han Chinese – cannot get enough oxygen to their tissues, and experience altitude sickness. They get headaches, tire easily, and have lower birth rates and higher child mortality than high-altitude populations.

Tibetans have none of these problems, despite having lower oxygen saturation in their tissues and a lower red blood cell count than the Han Chinese.

Around the world, populations have adapted to life at high altitude in different ways. One adaptation involves making more red blood cells, which transport oxygen to the body’s tissues. Indigenous people in the Peruvian Andes have higher red blood cell counts than their countrymen living at sea level, for example.

But Tibetans have evolved a different method. “Tibetans have the highest expression levels for EPAS1 in the world,” said co-author Dr Jian Wang of the Beijing Genomics Institute in Schenzhen, China, a research facility that collected the data. “For Western people, after two to three weeks at altitude, the red blood cell count starts to increase. But Tibetans and Sherpas keep the same levels,” he said.

“I just summitted Everest a few weeks ago,” added Dr Wang. He said the Sherpas and Tibetans were much stronger than the Westerners or lowland Chinese on the climb. “Their tissue oxygen concentration is almost the same as Westerners and Chinese but they are strong,” he said “and their red blood cell count is not that high compared to people in Peru.”

“The remarkable thing about Tibetans is that they can function well in high altitudes without having to produce so much haemoglobin,” said Prof Nielsen. “The entire mechanism is not well-understood – but is seems that the gene responsible is EPAS1.”

Nielsen said the gene is involved in regulating anaerobic and anaerobic metabolism in the body (cell respiration with and without oxygen). “It may be that the [mutated gene] helps balance anaerobic versus aerobic metabolism in a way that is more optimal for the low-oxygen environment of the Tibetan plateau,” he said.

Writing in Science, where the results are published today, the authors say: “EPAS1 may therefore represent the strongest instance of natural selection documented in a human population, and variation at this gene appears to have had important consequences for human survival and/or reproduction in the Tibetan region.”

Dr Wang said future research will focus on comparing the levels of EPAS1 expression in the placentas of Tibetan and Han Chinese women.

It seemed inconceivable, above all, that the Sentinelese islanders could have survived, living as they did on a remote island directly in the tsunami’s path.

The photo that told the world the Sentinelese had survived the 2004 tsunami.

Yet when a helicopter flew low over the island, a Sentinelese man rushed out on to the beach, aiming his arrow at the pilot in a gesture that clearly said, ‘We don’t want you here’. Alone of the tens of millions of people affected by the disaster, the Sentinelese needed no help from anyone.

Perhaps no people on Earth remain more genuinely isolated than the Sentinelese. They are thought to be directly descended from the first human populations to emerge from Africa, and have probably lived in the Andaman Islands for up to 60,000 years. The fact that their language is so different even from other Andaman islanders suggests that they have had little contact with other people for thousands of years.

This does not mean, however, that they live just as they did 60,000 years ago. Commonly described, for instance, as belonging to the ‘Stone Age’, they do in fact make tools and weapons from metal, which they recover from ships wrecked on the island’s reefs.

The Sentinelese are believed to have lived on their island home for 60,000 years.

Like so many isolated tribal people with a fearsome reputation, the Sentinelese are often inaccurately described as ‘savage’ or ‘backward’. Their hostility to outsiders, though, is easily understandable, for the outside world has brought them little but violence and contempt.

In 1879, for example, an elderly couple and some children were taken by force and brought to the islands’ main town, Port Blair. The colonial officer in charge of the kidnapping wrote that the entire group, ‘sickened rapidly, and the old man and his wife died, so the four children were sent back to their home with quantities of presents.’ Despite being responsible for the deaths of at least two people, and quite possibly starting an epidemic amongst the islanders, the same officer expressed no remorse, but merely remarked on the Sentinelese’s ‘peculiarly idiotic expression of countenance, and manner of behaving.’

The Sentinelese enjoy excellent health, unlike those Andamans tribes whose lands have been destroyed.

How far this is from the truth can be easily judged from a video of the Sentinelese on the island’s beach taken during an Indian government ‘contact’ expedition in the 1990s.

The islanders are clearly extremely healthy, alert and thriving, in marked contrast to the two Andaman tribes who have ‘benefited’ from Western civilization, the Onge and the Great Andamanese, whose numbers have crashed and who are now largely dependent on state handouts just to survive.

Pressure from Survival and other organisations has led the Indian government to alter its policy towards the Sentinelese, from attempting to make contact, to recognising that similar policies have proved disastrous for other Andaman tribes, and accepting that they have the right to decide for themselves how they wish to live. Underpinning this shift is the simple acknowledgment that the people themselves are best placed to decide what is in their own interests.

NEANDERTHALS as innovators? That the concept seems amusing goes to show how our sister species has become the butt of our jokes. Yet in the Middle Palaeolithic, some 300,000 years ago, innovation is what the Neanderthals were up to.

From NewScientist, by Rowan Hooper

This period is usually regarded as undramatic in cultural and evolutionary terms, with little in the way of technological or cognitive development. Palaeoanthropologists get more excited about the changes in tools found later, as the Middle Palaeolithic gave way to the Upper, and as modern humans replaced Neanderthals, some 40,000 years ago.

Terry Hopkinson of the University of Leicester, UK, has now challenged this view, showing that Neanderthals were far from behaviourally static. They incorporated different forms of tool construction into a single technique, and learned to cope with the ecological challenges posed by habitats in eastern Europe.

“There has been a consensus that the modern human mind turned on like a light switch about 50,000 years ago, only in Africa,” says Hopkinson. But the putatively modern traits accompanying the change, such as abstract art, the use of grindstones and elongated stone blades, and big game hunting began to accumulate in Africa from 300,000 years ago, he says. “It was the same in Europe with Neanderthals, there was a gradual accumulation of technology.” If Homo sapiens developed human traits gradually, then why not Neanderthals?

As with Homo sapiens in Africa, Neanderthals gradually accumulated technology and developed human traits

Archaeological finds from across Europe show that the Neanderthals fused two forms of toolmaking, the façonnage and the débitage techniques. In the former a stone core is shaped by chipping off flakes of flint, the latter involves producing sharp-edged flakes from a core. In the Lower Palaeolithic, more than 300,000 years ago, the two techniques were practised separately, but Hopkinson argues that during the Middle Palaeolithic they were fused into a single method, the Levallois reduction technique (Antiquity, vol 81, p 294).

At the same time as this was occurring, excavations show that Neanderthals spread into central and eastern Europe, regions where they and their forebears, Homo heidelbergensis, had hitherto been unable to settle. In western Europe, the influence of the Atlantic ameliorates the extreme seasonality of the continent, but away from this, the environment was too harsh for them to cope. “The eastern expansion shows that the Neanderthals became capable of managing their lives and their landscapes in strongly seasonal environments,” says Hopkinson.

This period is commonly thought to be characterised by long periods of little change in technological and perhaps also cognitive development, says Katerina Harvati of the department of human evolution at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “This analysis highlights important aspects of Neanderthal cultural and cognitive evolution which are not always emphasised,” she says.

Neanderthals have typically been thought of as incapable of innovation, as it was assumed to be something unique to Homo sapiens, says Hopkinson. “With this evidence of innovation it becomes difficult to exclude Neanderthals from the concept of humanity.”

By Jerry Fodor and Massimo Piattelli-Palmarini, from the NewScientist

Much of the vast neo-Darwinian literature is distressingly uncritical.
The possibility that anything is seriously amiss with Darwin’s account
of evolution is hardly considered. Such dissent as there is often
relies on theistic premises which Darwinists rightly say have no place
in the evaluation of scientific theories. So onlookers are left with
the impression that there is little or nothing about Darwin’s theory to
which a scientific naturalist could reasonably object. The
methodological scepticism that characterises most areas of scientific
discourse seems strikingly absent when Darwinism is the topic.

Try these descriptions of natural selection, typical of the laudatory
epithets which abound in the literature: “The universal acid”
(philosopher Daniel Dennett in Darwin’s Dangerous Idea, 1995); “a
mechanism of staggering simplicity and beauty… [it] has been called
the greatest idea that anyone ever had… it also happens to be true”
(biologist Jerry Coyne in Why Evolution is True, 2009); “the only
workable theory ever proposed that is capable of explaining life we
have” (biologist and ethologist Richard Dawkins, variously). And as
Dennett continues in Darwin’s Dangerous Idea: “In a single stroke, the
idea of evolution by natural selection unifies the realm of life,
meaning, and purpose with the realm of space and time, cause and
effect, mechanism and physical law.”

Golly! Could Darwinism really be that good?

Darwin’s theory of evolution has two connected parts: connected, but
not inseparable. First, there is an explanation of the taxonomy of
species. It is an ancient observation that if you sort species by
similarities among their phenotypes (a phenotype being a particular
creature’s collection of overt, heritable biological properties) they
form the hierarchy known as a “taxonomic tree”.

This is why most vertebrate species are more similar to one another
than they are to any invertebrate species, most species of mammals are
more similar to one another than they are to any species of reptiles,
and so forth. Why is this? It is quite conceivable that every species
might be equally different from every other. What explains why they
aren’t?

Darwin suggested a genealogical hypothesis: when species are relatively
similar, it’s because they are descended from a relatively recent
common ancestor. In some ways, chimps seem a lot like people. This is
not because God created them to poke fun at us, or vice versa; it is
because humans and chimps are descended from the same relatively recent
primitive ape.

The current consensus is that Darwin was almost certainly right about
this. There are plausible exceptions, notably similarities that arise
from evolutionary convergence, but evidence from a number of
disciplines, including genetics, evolutionary developmental biology and
palaeontology argues decisively for Darwin’s historical account of the
taxonomy of species. We agree that this really was as brilliant an idea
as it is generally said to be.

But that cannot be the whole story, since it is not self-evident why
species that have a recent common ancestor–as opposed, say, to
species that share an ecology–are generally phenotypically similar.
Darwin’s theory of natural selection is intended to answer this
question. Darwinists often say that natural selection provides the
mechanism of evolution by offering an account of the transmission of
phenotypic traits from generation to generation which, if correct,
explains the connection between phenotypic similarity and common
ancestry.

Moreover, it is perfectly general: it applies to any species,
independent of what its phenotype may happen to be. And it is
remarkably simple. In effect, the mechanism of trait transmission it
postulates consists of a random generator of genotypic variants that
produce the corresponding random phenotypic variations, and an
environmental filter that selects among the latter according to their
relative fitness. And that’s all. Remarkable if true.

Compelling evidence

But we don’t think it is true. A variety of different considerations
suggesting that it is not are mounting up. We feel it is high time that
Darwinists take this evidence seriously, or offer some reason why it
should be discounted. Our book about what Darwin got wrong reviews in
detail some of these objections to natural selection and the evidence
for them; this article is a brief summary.

Here’s how natural selection is supposed to work. Each generation
contributes an imperfect copy of its genotype–and thereby of its
phenotype–to its successor. Neo-Darwinism suggests that such
imperfections arise primarily from mutations in the genomes of members
of the species in question.

What matters is that the alterations of phenotypes that the mechanisms
of trait transmission produce are random. Suppose, for example, that a
characteristic coloration is part of the phenotype of a particular
species, and that the modal members of the ith generation of that
species are reddish brown. Suppose, also, that the mechanisms that copy
phenotypes from each generation to the next are “imperfect” in the
sense given above. Then, all else being equal, the coloration of the i
+ 1th generation will form a random distribution around the mean
coloration of the parent generation: most of the offspring will match
their parents more or less, but some will be more red than brown, and
some will be more brown than red.

This assumption explains the random variation of phenotypic traits over
time, but it doesn’t explain why phenotypic traits evolve. So let’s
further assume that, in the environment that the species inhabits, the
members with brownish coloration are more “fit” than the ones with
reddish coloration, all else being equal. It doesn’t much matter
exactly how fitness is defined; for convenience, we’ll follow the
current consensus according to which an individual’s relative fitness
co-varies with the probability that it will contribute its phenotypic
traits to its offspring.

Given a certain amount of conceptual and mathematical tinkering, it
follows that, all else again being equal, the fitness of the species’s
phenotype will generally increase over time, and that the phenotypes of
each generation will resemble the phenotype of its recent ancestors
more than they resemble the phenotypes of its remote ancestors.

That, to a first approximation, is the neo-Darwinian account of how
phenotypes evolve. To be sure, some caveats are required. For example,
even orthodox Darwinists have always recognised that there are plenty
of cases where fitness doesn’t increase over time. So, for example,
fitness may decrease when a population becomes unduly numerous (that’s
density-dependent selection at work), or when a species having once
attained a “fitness plateau” then gets stuck there, or, of course, when
the species becomes extinct.

Such cases do not show that neo-Darwinism is false; they only show that
the “all else being equal” clauses must be taken seriously. Change the
climate enough and the next generation of dinosaurs won’t be more fit
than its parents. Hit enough dinosaurs with meteors, and there won’t be
a next generation. But that does not argue against Darwinian selection,
as this claims only to say what happens when the ecology doesn’t
change, or only changes very gradually, which manifestly does not apply
in the case of the dinosaurs and the meteorite strikes.

So much for the theory, now for the objections. Natural selection is a
radically environmentalist theory. There are, therefore, analogies
between what Darwin said about the process of evolution of phenotypes
and what the psychologist B. F. Skinner said about the learning of what
he called “operant behaviour”–the whole network of events and factors
involved in the behaviour of humans and non-human animals.

Driven from within

These analogies are telling. Skinner’s theory, though once fashionable,
is now widely agreed to be unsustainable, largely because Skinner very
much overestimated the contribution that the structure of a creature’s
environment plays in determining what it learns, and correspondingly
very much underestimated the contribution of the internal or
“endogenous” variables–including, in particular, innate cognitive
structure.

In our book, we argue in some detail that much the same is true of
Darwin’s treatment of evolution: it overestimates the contribution the
environment makes in shaping the phenotype of a species and
correspondingly underestimates the effects of endogenous variables. For
Darwin, the only thing that organisms contribute to determining how
next-generation phenotypes differ from parent-generation phenotypes is
random variation. All the non-random variables come from the
environment.

Suppose, however, that Darwin got this wrong and various internal
factors account for the data. If that is so, there is inevitably less
for environmental filtering to do.

The consensus view among neo-Darwinians continues to be that evolution
is random variation plus structured environmental filtering, but it
seems the consensus may be shifting. In our book we review a large and
varied selection of non-environmental constraints on trait
transmission. They include constraints imposed “from below” by physics
and chemistry, that is, from molecular interactions upwards, through
genes, chromosomes, cells, tissues and organisms. And constraints
imposed “from above” by universal principles of phenotypic form and
self-organisation–that is, through the minimum energy expenditure,
shortest paths, optimal packing and so on, down to the morphology and
structure of organisms.

Over the aeons of evolutionary time, the interaction of these multiple
constraints has produced many viable phenotypes, all compatible with
survival and reproduction. Crucially, however, the evolutionary process
in such cases is not driven by a struggle for survival and/or for
reproduction. Pigs don’t have wings, but that’s not because winged pigs
once lost out to wingless ones. And it’s not because the pigs that
lacked wings were more fertile than the pigs that had them. There never
were any winged pigs because there’s no place on pigs for the wings to
go. This isn’t environmental filtering, it’s just physiological and
developmental mechanics.

So, how many constraints on the evolution of phenotypes are there other
than those that environmental filtering imposes? Nobody knows, but the
picture now emerging is of many, many of them operating in many, many
different ways and at many, many different levels. That’s what the
evolutionary developmental school of biology and the theory that gene
regulatory networks control our underlying development both suggest.
And it strikes us as entirely plausible.

It seems to us to be no coincidence that neo-Darwinian rhetoric in the
literature of experimental biology has cooled detectably in recent
years. In its place, we find evolutionary biologist Leonid Kruglyak
being quoted in Nature in November 2008 (vol 456, p 18) thus: “It’s a
possibility that there’s something [about the contributions of genomic
structure to the evolution of complex phenotypes] we just don’t
fundamentally understand… That it’s so different from what we’re
thinking about that we’re not thinking about it yet.”

And then there is this in March 2009 from molecular biologist Eugene
Koonin, writing in Nucleic Acids Research (vol 37, p 1011):
“Evolutionary-genomic studies show that natural selection is only one
of the forces that shape genome evolution and is not quantitatively
dominant, whereas non-adaptive processes are much more prominent than
previously suspected.” There’s quite a lot of this sort of thing around
these days, and we confidently predict a lot more in the near future.

Darwinists say that evolution is explained by the selection of
phenotypic traits by environmental filters. But the effects of
endogenous structure can wreak havoc with this theory. Consider the
following case: traits t[1] and t[2] are endogenously linked in such a
way that if a creature has one, it has both. Now the core of natural
selection is the claim that phenotypic traits are selected for their
adaptivity, that is, for their effect on fitness. But it is perfectly
possible that one of two linked traits is adaptive but the other isn’t;
having one of them affects fitness but having the other one doesn’t. So
one is selected for and the other “free-rides” on it.

We should stress that every such case (and we argue in our book that
free-riding is ubiquitous) is a counter-example to natural selection.
Free-riding shows that the general claim that phenotypic traits are
selected for their effects on fitness isn’t true. The most that natural
selection can actually claim is that some phenotypic traits are
selected for their effects on fitness; the rest are selected for…
well, some other reason entirely, or perhaps for no reason at all.

It’s a main claim of our book that, when phenotypic traits are
endogenously linked, there is no way that selection can distinguish
among them: selection for one selects the others, regardless of their
effects on fitness. That is a great deal less than the general theory
of the mechanics of evolution that the Darwinists suppose that natural
selection provides. Worse still, there isn’t the slightest reason to
suppose that free-riding exhausts the kinds of exceptions to natural
selection that endogenous structures can produce.

“All right,” you may say, “but why should anybody care?” Nobody
sensible doubts that evolution occurs–we certainly don’t. Isn’t this
a parochial issue for professional biologists, with nothing cosmic
turning on it? Here’s why we think that is not so.

Natural selection has shown insidious imperialistic tendencies. The
offering of post-hoc explanations of phenotypic traits by reference to
their hypothetical effects on fitness in their hypothetical
environments of selection has spread from evolutionary theory to a host
of other traditional disciplines: philosophy, psychology, anthropology,
sociology, and even to aesthetics and theology. Some people really do
seem to think that natural selection is a universal acid, and that
nothing can resist its powers of dissolution.

However, the internal evidence to back this imperialistic selectionism
strikes us as very thin. Its credibility depends largely on the
reflected glamour of natural selection which biology proper is said to
legitimise. Accordingly, if natural selection disappears from biology,
its offshoots in other fields seem likely to disappear as well. This is
an outcome much to be desired since, more often than not, these
offshoots have proved to be not just post hoc but ad hoc, crude,
reductionist, scientistic rather than scientific, shamelessly
self-congratulatory, and so wanting in detail that they are bound to
accommodate the data, however that data may turn out. So it really does
matter whether natural selection is true.

That’s why we wrote our book.

Profile

Jerry Fodor is a philosopher and cognitive scientist at Rutgers
University, New Jersey. Massimo Piattelli-Palmarini is a cognitive
scientist at the University of Arizona, Tucson. This essay draws on
material from their new book, What Darwin Got Wrong, published in the
US by Farrar, Straus, and Giroux, and in the UK by Profile

By Elaine Morgan

The most widely held theory, still taught in schools and universities, is that we are descended from apes which moved out of the forests onto the grasslands of the open savannah. The distinctly human features are thus supposed to be adaptations to a savannah environment.

In that case, we would expect to find at least some of these adaptations to be paralleled in other savannah mammals. But there is not a single instance of this, not even among species like baboons and vervets, which are descended from forest- dwelling ancestors.

This awkward fact has not caused savannah theorists to abandon their hypothesis, but it leaves a lot of problems unanswered. For example, on the question of why humans lost their body hair, it has been argued at various times that no explanation is called for, or that we may never know the reason, or even that there may not be a reason. These attitudes seem to be not merely defeatist, but fundamentally unscientific.

The Aquatic Ape Theory (AAT) offers an alternative scenario. It suggests that when our ancestors moved onto the savannah they were already different from the apes; that nakedness, bipedalism, and other modifications had begun to evolve much earlier, when the ape and human lines first diverged.

AAT points out that most of the “enigmatic” features of human physiology, though rare or even unique among land mammals, are common in aquatic ones. If we postulate that our earliest ancestors had found themselves living for a prolonged period in a flooded, semi-aquatic habitat, most of the unsolved problems become much easier to unravel.

There is powerful geological evidence to support this hypothesis, and nothing in the fossil record that is inconsistent with it. Some of the issues it raises are briefly outlined in the following pages.

The naked ape

Humans are classed anatomically among the primates, the order of which includes apes, monkeys and lemurs. Among the hundreds of living primate species, only humans are naked.

Two kinds of habitat are known to give rise to naked mammals – a subterranean one or a wet one. There is a naked Somalian mole rat which never ventures above ground. All other non-human mammals which have lost all or most of their fur are either swimmers like whales and dolphins and walruses and manatees, or wallowers like hippopotamuses and pigs and tapirs. The rhinoceros and the elephant, though found on land since Africa became drier, bear traces of a more watery past and seize every opportunity of wallowing in mud or water.

It has been suggested that humans became hairless “to prevent overheating in the savannah”. But no other mammal has ever resorted to this strategy. A covering of hair acts as a defense against the heat of the sun: that is why even the desert- dwelling camel retains its fur. Another version is “to facilitate sweat-cooling”. But again many species resort to sweat-cooling quite effectively without needing to lose their hair.

There is no known reason why an ape should suffer more from overheating than the savannah baboon. And, especially for a savannah primate, there would be a high price to pay for hairlessness. Primate infants are carried around clinging to their mothers’ fur; the females would be severely hampered in their foraging when that no longer became possible.

One general conclusion seems undeniable from an overall survey of mammalian species: that while a coat of fur provides the best insulation for land mammals the best insulation in water is not fur, but a layer of fat.

Fat

Humans are by far the fattest primates; we have ten times as many fat cells in our bodies as would be expected in an animal of our size.

There are two kinds of animals which tend to acquire large deposits of fat – hibernating ones and aquatic ones. In hibernating mammals the fat is seasonal; in most aquatic ones, as in humans it is present all the year round. Also, in land mammals fat tends to be stored internally, especially around the kidneys and intestines; in aquatic mammals and in humans a higher proportion is deposited under the skin.

It is unlikely that early man would have evolved this feature after moving to the plains and becoming a hunter, because it would have slowed him down. No land-based predator can afford to get fat. Our tendency to put on fat is likelier to be an inheritance from an earlier aquatic phase of our evolution. It is true that some apes, especially in captivity, may put on weight, but we still differ from them in two important ways. One is that they are never born fat. All infant primates except our own are slender; their lives may depend on their ability to cling to their mothers and support their whole weight with their fingers. Our own babies accumulate fat even before birth and continue to grow fatter for several months afterwards. Some of this fat is white fat, and that is extremely rare in new-born mammals. White fat is not much good for supplying instant heat and energy. It is good for insulation in water, and for giving buoyancy.

The other difference is that in our case the subcutaneous fat is bonded to the skin. When an anatomist skins a cat or rabbit or chimpanzee, any superficial fat deposits remain attached to the underlying tissues. In the case of humans, the fat comes away with the skin, just as it does in aquatic species like dolphins, seals, hippos and manatees.

Walking on two legs

Human beings are the only mammals in the world that habitually walk on two legs. (The only other creature with a perpendicular gait is an aquatic bird, the penguin.)

It is not surprising bipedalism is so rare. Compared with running or walking on four legs it has many disadvantages. It is slower; it is relatively unstable; it is a skill that takes many years to learn, and it exposes vulnerable organs to attack.

We have been doing it for five million years and in that time our bodies have been drastically remoulded to make it easier, but it is still the direct cause of many discomforts and ailments such as back pains, varicose veins, haemorrhoids, hernias and problems in childbirth. It would have been far more difficult and laborious for our ape-like ancestors; only some powerful pressure could have induced them to adopt a way of walking for which they were initially so ill suited.

One hypothesis used to be that they first developed big brains and began to make tools, and finally walked on their hind legs to free their hands for carrying weapons. But we now know that it was bipedalism that came first, before the big brain and tool-making.

However, if their habitat had become flooded, they would have been forced to walk on their hind legs whenever they came down to the ground in order to keep their heads above water. The only animal which has ever evolved a pelvis like ours, suitable for bipedalism, was the long-extinct _Oreopithecus_, known as the swamp ape.

Today, two primates when on the ground stand and walk erect somewhat more readily than most other species. One, the proboscis monkey, lives in the mangrove swamps of Borneo. The other is the bonobo or pygmy chimpanzee; its habitat includes a large tract of seasonally flooded forest, which would have covered an even more extensive area before the African climate became drier.

Both of these species enjoy the water. It is interesting that the bonobos often mate face-to-face as humans do; in our case it is explained as a consequence of bipedalism. This mode of mating is another characteristic very rare among land animals, which we share with a wide range of aquatic mammals such as dolphins, beavers and sea otters. What we have in common with them is a mode of locomotion in which the spine and the hind limbs are in a straight line, and that affects the position of the sex organs.

Breathing

The human respiratory system is unlike any other land mammal’s in two respects.

The first is that we have conscious control of our breathing. In most mammals these actions are involuntary, like the heart beat or the processes of digestion.

Voluntary breath control appears to be an aquatic adaptation because, apart from ourselves, it is found only in aquatic mammals like seals and dolphins. When they decide how deep they are going to dive, they can estimate how much air they need to inhale. Without voluntary breath control it is very unlikely that we could have learned to speak.

The other human peculiarity is called “the descended larynx”. A land mammal is normally obliged to breathe through its nose most of the time, because its windpipe passes up through the back of the throat and the top end of it (the larynx) is situated in the back of its nasal passages. A dog, for example, has to make a special effort to bring its larynx down into its throat in order to bark or to pant; when it relaxes, the larynx goes back up again. Even our own babies are born like that.

A few months after birth the human larynx descends into the throat, right down below the back of the tongue. Darwin found that very puzzling because it means that the opening to the lungs lies side by side with the opening to the stomach. That is why in our species food and drink may sometimes go “down the wrong way”. If we had not evolved an elaborate swallowing mechanism it would happen every time.

This arrangement means that we can breathe through our mouths as easily as through our noses. It is probable that this is an aquatic adaptation, because a swimmer needing to gulp air quickly can inhale more of it through the mouth than through the nostrils. And we do know that the only birds which are obligatory mouth breathers are diving birds like penguins, pelicans and gannets. As for mammals, the only ones with a descended larynx, apart from ourselves, are aquatic ones – the sea lion and the dugong.

Other differences

It is impossible in a brief outline to discuss all the physical features distinguishing us from the apes, but a few are worth mentioning.

For example, we have a different way of sweating from other mammals, using different skin glands. It is very wasteful of the body’s essential resources of water and salt. It is therefore unlikely that we acquired it on the savannah, where water and salt are both in short supply.

We weep tears of emotion, controlled by different nerves from the ones that cause our eyes to water in response to smoke or dust. No other land animal does this. There are marine birds, marine reptiles and marine mammals which shed water through their eyes, or through special nasal glands, when they have swallowed too much seawater. This process may also be triggered in them by an emotional excitement caused by feeding or fighting or frustration. Weeping animals, apart from ourselves, include the walrus, the seal and the sea otter.

We have millions of sebaceous glands which exude oil over head, face and torso, and in young adults often causes acne. The chimpanzee’s sebaceous glands are described as “vestigial” whereas ours are described as “enormous”. Their purpose is obscure. In other animals the only known function of sebum is that of waterproofing the skin or the fur.

The most widely discussed contrast between ourselves and the apes is that we have bigger brains. A bigger brain may well have been an advantage to early man, but it would have been equally of advantage to a chimpanzee: the question is why one of them acquired it.

One factor may have been nutritional. The building of brain tissue, unlike other body tissues, is dependent on an adequate supply of Omega-3 fatty acids, which are abundant in the marine food chain but relatively scarce in the land food chain.

AAT is the only theory which logically connects all these and other enigmatic features and relates them to a single well attested historical event.

The time and the place

It is now generally agreed that the man/ape split occurred in Africa between 7 and 5 million years ago, during a period known as the fossil gap.

Before it there was an animal which was the common ancestor of human and African apes. After it, there emerged a creature smaller than ourselves, but bearing the unmistakable hallmark of the first shift towards human status: it walked on two legs.

This poses two questions: “Where were the earliest fossils found?” and “Do we know of anything happening in that place at that time that might have caused apes and humans to evolve along separate lines?”

The oldest pre-human fossils (including the best known one, “Lucy”) are called australopithecus afarensis because their bones were discovered in the afar triangle, and area of low lying land near the Red Sea. About 7 million years ago that area was flooded by the sea and became the Sea of Afar.

Part of the ape population living there at the time would have found themselves living in a radically changed habitat. Some may have been marooned on off-shore islands – the present day Danakil Alps were once surrounded by water. Others may have lived in flooded forests, salt marshes, mangrove swamps, lagoons or on the shores of the new sea, and they would all have had to adapt or die.

AAT suggests that some of them survived, and began to adapt to their watery environment. Much later, when the Sea of Afar became landlocked and finally evaporated, their descendants returned to the mainland of Africa and began to migrate southwards, following the waterways of the Rift Valley upstream.

There is nothing in the fossil record to invalidate this scenario, and much to sustain it. Lucy’s bones were found at Afar lying among crocodile and turtle eggs and crab claws at the edge of a flood plain near what would then have been the coast of Africa.

Other fossils of Australopithecus, dated later, were found further south, almost invariably in the immediate vicinity of ancient lakes and rivers.

We now know that the change from the ape into Australopithecus took place in a short space of time, by evolutionary standards. Such rapid speciation is almost invariably a sign that one population of a species has become isolated by a geographical barrier such as a stretch of water.

The Aquatic phase took place more than 5 million years ago. Since then, Homo has had five million years to re-adapt to terrestrial life. It is not surprising that the traces of aquatic adaptation have become partially obliterated and have gone unrecognized for so long.

By George Monbiot. Published in the Guardian 20th November 2009

When you think of Canada, which qualities come to mind? The world’s peace-keeper, the friendly nation, a liberal counterweight to the harsher pieties of its southern neighbour, decent, civilised, fair, well-governed? Think again. This country’s government is now behaving with all the sophistication of a chimpanzee’s tea party. So amazingly destructive has Canada become, and so insistent have my Canadian friends been that I weigh into this fight, that I’ve broken my self-imposed ban on flying and come to Toronto.

So here I am, watching the astonishing spectacle of a beautiful, cultured nation turning itself into a corrupt petrostate. Canada is slipping down the development ladder, retreating from a complex, diverse economy towards dependence on a single primary resource, which happens to be the dirtiest commodity known to man. The price of this transition is the brutalisation of the country, and a government campaign against multilateralism as savage as any waged by George Bush.

Until now I believed that the nation which has done most to sabotage a new climate change agreement was the United States. I was wrong. The real villain is Canada. Unless we can stop it, the harm done by Canada in December 2009 will outweigh a century of good works.

In 2006 the new Canadian government announced that it was abandoning its targets to cut greenhouse gases under the Kyoto Protocol. No other country that had ratified the treaty has done this. Canada was meant to have cut emissions by 6% between 1990 and 2012. Instead they have already risen by 26%(1).

It’s now clear that Canada will refuse to be sanctioned for abandoning its legal obligations. The Kyoto Protocol can be enforced only through goodwill: countries must agree to accept punitive future obligations if they miss their current targets. But the future cut Canada has volunteered is smaller than that of any other rich nation(2). Never mind special measures; it won’t accept even an equal share. The Canadian government is testing the international process to destruction and finding that it breaks all too easily. By demonstrating that climate sanctions aren’t worth the paper they’re written on, it threatens to render any treaty struck at Copenhagen void.

After giving the finger to Kyoto, Canada then set out to prevent the other nations from striking a successor agreement. At the end of 2007 it single-handedly blocked a Commonwealth resolution to support binding targets for industrialised nations(3). After the climate talks in Poland in December 2008, it won the Fossil of the Year award, presented by environmental groups to the country which had done most to disrupt the talks(4). The climate change performance index, which assesses the efforts of the world’s 60 richest nations, was published in the same month. Saudi Arabia came 60th. Canada came 59th(5).

In June this year the media obtained Canadian briefing documents which showed that the government was scheming to divide the Europeans(6). During the meeting in Bangkok in October, almost the entire developing world bloc walked out when the Canadian delegate was speaking, as they were so revolted by his bullying(7). Last week the Commonwealth heads of government battled for hours (and eventually won) against Canada’s obstructions. A concerted campaign has now begun to expel Canada from the Commonwealth(8).

In Copenhagen next week, this country will do everything in its power to wreck the talks. The rest of the world must do everything in its power to stop it. But such is the fragile nature of climate agreements that one rich nation – especially a member of the G8, the Commonwealth and the Kyoto group of industrialised countries – could scupper the treaty. Canada now threatens the well-being of the world.

Why? There’s a simple answer. Canada is developing the world’s second largest reserve of oil. Did I say oil? It’s actually a filthy mixture of bitumen, sand, heavy metals and toxic organic chemicals. The tar sands, most of which occur in Alberta, are being extracted by the biggest opencast mining operation on earth. An area the size of England, of pristine forests and marshes, will be dug up, unless the Canadians can stop this madness. Already it looks like a scene from the end of the world: the strip-miners are creating a churned black hell on an unimaginable scale.

To extract oil from this mess, it needs to be heated and washed. Three barrels of water are used to process one barrel of oil(9). The contaminated water is held in vast tailing ponds, some of which are so toxic that the tar companies employ people to scoop dead birds off the surface(10). Most are unlined. They leak organic poisons, arsenic and mercury into the rivers. The First Nations people living downstream have developed a range of exotic cancers and auto-immune diseases(11).

Refining tar sands requires two to three times as much energy as refining crude oil. The companies exploiting them burn enough natural gas to heat six million homes(12). Alberta’s tar sands operation is the world’s biggest single industrial source of carbon emissions(13). By 2020, if the current growth continues, it will produce more greenhouse gases than Ireland or Denmark(14). Already, thanks in part to the tar mining, Canadians have almost the highest per capita emissions on earth, and the stripping of Alberta has scarcely begun.

Canada hasn’t acted alone. The biggest leaseholder in the tar sands is Shell(15), a company that has spent millions persuading the public that it respects the environment. The other great greenwasher, BP, initially decided to stay out of tar. Now it has invested in plants built to process it(16). The British bank RBS, 70% of which belongs to you and me (the government’s share will soon rise to 84%), has lent or underwritten £8bn for exploiting the tar sands(17).

The purpose of Canada’s assault on the international talks is to protect this industry. This is not a poor nation. It does not depend for its economic survival on exploiting this resource. But the tar barons of Alberta have been able to hold the whole country to ransom. They have captured Canada’s politics and are turning this lovely country into a cruel and thuggish place.

Canada is a cultured, peaceful nation, which every so often allows a band of rampaging Neanderthals to trample all over it. Timber companies were licensed to log the old-growth forest in Clayaquot Sound; fishing companies were permitted to destroy the Grand Banks: in both cases these get-rich-quick schemes impoverished Canada and its reputation. But this is much worse, as it affects the whole world. The government’s scheming at the climate talks is doing for its national image what whaling has done for Japan.

I will not pretend that this country is the only obstacle to an agreement at Copenhagen. But it is the major one. It feels odd to be writing this. The immediate threat to the global effort to sustain a peaceful and stable world comes not from Saudi Arabia or Iran or China. It comes from Canada. How could that be true?

www.monbiot.com

References:

1. http://www.ec.gc.ca/pdb/ghg/inventory_report/2007/som-sum_eng.cfm

2. The government has pledged to match the (feeble) US 2020 target (which in Canada’s case means just 3% against 1990 levels) , but unlike the United States, Canada has proposed no cuts beyond that date.

3. Eg http://www.canada.com/story_print.html?id=a1a6748c-ef0c-4acf-acad-1cef2bdae5b7&sponsor=

4. Andrew Nikiforuk, September 2009. How The Tar Sands Are Fueling The Global Climate Crisis.
Greenpeace Canada. ***

5. http://www.germanwatch.org/klima/ccpi09res.pdf

6. Lee Berthiaume, 17th June 2009. Government Planned to Split EU On Climate Change Talks. Embassy Magazine. Cited by Andrew Nikiforuk, ibid.

7. http://www.ctv.ca/servlet/ArticleNews/print/CTVNews/20091012/kyoto_091012/20091012/?hub=Canada&subhub=PrintStory

8. http://www.guardian.co.uk/environment/2009/nov/26/canada-criticised-over-climate-change

9. WWF, 2008. Scraping the Bottom of the Barrel?, Page 27.

http://assets.panda.org/downloads/unconventional_oil_final_lowres.pdf

10. http://peopleandplanet.org/tarsands/localimpacts

11. Environmental Defence, February 2008. Canada’s Toxic Tar Sands: the most destructive project on earth.

http://www.environmentaldefence.ca/reports/pdf/TarSands_TheReport.pdf

12. Andrew Nikiforuk, ibid.

13. http://peopleandplanet.org/tarsands/localimpacts

14. Andrew Nikiforuk, ibid.

15. ibid.

16. ibid.

17. Ed Crooks, 16th November 2009. Canadian Protest Over RBS Oil Sands Role. The Financial Times.

This event was moderated by Faith Salie and features author Jonathan Rosen; neurobiologist Erich Jarvis; scientist and noted bird researcher Irene Pepperberg; professor of comparative cognition at Cambridge University, Nicola Clayton; Head of the Laboratory of Animal Behavior at CUNY, Ofer Tchernichovski; and David Rothenberg, professor of philosophy and music at the New Jersey Institute of Technology.

“Avian Einsteins” also features a special appearance by Snowball, the famous dancing cockatoo, and owner, Irena Schulz.