New Scientist: Is Extinction Really Such a Bad Thing?

A new exhibit at London's Natural History Museum asks just that question and concludes that, no, it is not.  Shaoni Bhattacharya at The New Scientist's Culture Lab writes:

The five mass extinctions in Earth's history wiped out swathes of life, but out of the devastation new species rose - shaped and honed by evolution - to inherit the Earth. More than 99 per cent of species that ever lived are now dead, and the exhibition hammers home the point that extinction drives evolution, which results in life in all its wondrous forms.

But it tempers this message strongly with a second sobering one: human actions are causing extinctions in a way never before seen. "If we don't do anything about it, make no mistake - it will hugely affect the world we live in," says Adrian Lister, a palaeontologist at the museum whose work on the extinct Irish elk forms part of the exhibition. "It would take the biosphere millions of years to recover."

It's not all doom, though. There are upbeat stories on display - animals we drove to the brink but then saved through conservation efforts: the Californian condor, the Arabian oryx, and China's Pere David's deer.

We have many, many tales of extinction in our own "bush." The robust australopithecines, who got out-competed by early Homo and the Neandertals come to mind.  The case of the Neandertals is peculiar, however, because it looks like they interbred with modern humans before they got gene-swamped.  Regardless, it is out of their stock and those like them that we came.

As far as conservation goes, I certainly hope we learn to understand how important it is to have our great apes around. 

Gee, Who Knew?

Every so often, Science Daily comes out with a story that, perhaps needs to be restated but is amusing nevertheless. They write:

Climate changes profoundly influenced the rise and fall of six distinct, successive waves of mammal species diversity in North America over the last 65 million years, shows a novel statistical analysis led by Brown University evolutionary biologists. Warming and cooling periods, in two cases confounded by species migrations, marked the transition from one dominant grouping to the next.

I am quite sure that there is more to the Brown study than meets the eye since this information simply reflects what we already knew about how natural selection works in the wild. The story does, in fact, provide detailed information about mammal extinctions and radiations. It is the way in which Science Daily words the headline that is amusing.

This “lack of randomness” was the crux of a piece that I wrote for CFSI a bit back. If anti-evolutionists or ID supporters are willing to argue that evolution is a “godless, random process” then they have to be willing to argue that climate change on the planet is also a random, godless process, since that is what drives biotic change. I haven't heard any of them say that yet.

----------------
Now playing: Kansas - Magnum Opus
via FoxyTunes

Modern Humans Extinction-Proof?

Darren Curnoe is in the news again. Last year, he coined a new species at the boundary of late Australopithecus/early Homo, named Homo gautengensis, which made such a large splash in the community that there have since been ZERO articles on it from other researchers. It is classified as Homo habilis by everyone else. I asked my advisor about Homo gautengensis and he replied “Homo what?”

Curnoe is now arguing that humans are extinction-proof. Gavin Allen of the Mail Online writes:

There were around 100,000 hunter-gatherers in the Ice Age and now the worldwide population stands at approximately seven billion.

Curnoe says: ‘Seen in its broadest context, the history of life on Earth soberly demonstrates that the vast majority of organisms that ever lived, perhaps 99 per cent of them, no longer do’ wrote Curnoe.

‘It also shows that mammal species normally last 1-2 million years before extinction inevitably bumps them off.

‘Yet, unlike most mammals, including our dozens of extinct hominin cousins, we have escaped the vulnerabilities of a small and massively fluctuating population.

‘The simple, but profound act, of growing our own food delivered us the food security that ensured most of our children survived and our population grew.

‘In effect, farming gave our species level assurance that the biological isn’t always inevitable. The odds have shifted to such a degree that we may now be, with or without climate change, extinction-proof.’

Curnoe is certainly right that the advent of farming and agriculture significantly changed the environment and led to humans being able to control the landscape to a much greater degree but I would argue that as important was a change that took place much earlier in our history: the loss of estrus.

At some point in our past, humans acquired the ability to be continously sexed. We can procreate any time we want. This is important, given our reproductive strategy. Primates fall into the class of organisms that are “k-selected.” We usually have only one offspring at a time and we invest much energy and time in getting that child to reproductive age. The counter to this is an r-selected animal like the sea turtle, which lays over a hundred eggs in the hopes that some of them survive into adulthood. By the time they hatch, the mother turtle is long gone.

While it is certainly true that human babies born in winter had less of a chance of survival before the advent of modern technology and heating, to be able to mate at any opportunity vastly expands the ability of the population to increase quickly. Gorillas, on the other hand, can only procreate once every three years.

There have been extinctions in human history but there has also been species evolution resulting in the appearance of modern humans between 150 and 170 thousand years ago. Further, the technological advances with which we have surrounded ourselves were likely not an outgrowth of increasing intelligence but rather an increasing population, driven by the loss of estrus. Without some high level of food security, k-selected populations do not increase that fast.

It could, therefore, be equally argued that agriculture was an outgrowth of the need to feed large populations, and that it might not have been agriculture that made us "extinction-proof" but simply a large enough increase in the population to the point where it made us almost impossible to kill off.

P.S. As to whether or not we are extinction proof, one really large meteorite and we're toast.

Mammals Not So Extinct After All

A story out of Wired reports that many mammals that have been traditionally thought to be extinct may not be. Brian Switek writes:

In order to determine how often extinct species had been rediscovered, University of Queensland scientists Diana Fisher and Simon Blomberg created a dataset of 187 mammal species that have been reported extinct, extinct in the wild, or probably extinct since 1500, as well as those which have been rediscovered. They also looked at historical data on the threats that caused species to become extinct — or brought them close to it — including habitat loss, introduced species and overkill by humans.

It turns out that rumors of the extinction of more than a third of these species have turned out to be premature, the scientists report in Proceedings of the Royal Society B Sept. 29. At least 67 species — a little more than a third of those presumed to be extinct — were later found again. And in most cases, these were animals that had been hardest hit by habitat loss.

This is encouraging, but that doesn't mean you should pull out your elephant gun:

Humans and invasive species have been significantly more efficient killers. It’s rare that a species reported extinct due to one of these causes has been seen again.

“If you think that a missing species is extinct and the main cause of decline was introduced predators such as feral foxes, cats or rats, then you are very likely to be right,” Fisher said. But, she added, “If the main cause of decline was habitat loss, you are quite likely to be wrong if you say that it’s extinct, unless it was restricted to a very small area.”

Now the catch is if we can stop habitat loss in countries that need to survive and yet need to preserve their biodiversity. Not an easy thing to do in this day and age.

----------------
Now playing: Steve Hackett - Prayers and Dreams
via FoxyTunes

Dinosaur Extinction: "The Smoking Gun?"

ABC News is carrying a story about research performed by over forty different scientists that provides the strongest evidence yet that the reign of the dinosaurs came to an unceremonious end around 65 mya due to the impact of an asteroid the size of the Isle of Wight. Stuart Gary writes:

In this latest study, researchers examined the sedimentary material around the impact site and found it was far too violently churned up to provide a reliable dating record.

They found that farther away from the impact site, the sedimentary material becomes a single layer at the K-T boundary, matching the composition of rocks at Chicxulub.

They also determined that despite evidence for relatively active volcanism in India, ecosystems showed only minor changes within the 500,000 years before the K-T boundary event.

Only at the boundary do things suddenly change.

As the article notes, however, other scientists are not so convinced. One of my friends from graduate school said at the time that dinosaurs show steep decline ahead of the K-T boundary and that they hang around for awhile after the boundary, suggesting that other factors were at work. This is echoed by Steven Salisbury of the University of Queensland, who is quoted in the article.

----------------
Now playing: Derek & The Dominos - Layla
via FoxyTunes

Cretaceous Extinction: The Smoking Gun?

Canwest is reporting on research by Sankar Chatterjee, of Texas Tech University, who claims to have found the impact crater that led to the dinosaur extinction at the end of the Cretaceous period. They write:

The area is about 500 kilometres in diameter and encircles a peak about five kilometres high known as the Bombay High. It is also a spot mined extensively for oil and gas by companies that tend to keep their geological data secret, which has delayed the ability of researchers to do any in-depth research of the suspected crater.

A bit later, they write:

Chatterjee said the crater is likely the largest on the planet and was caused by an object about 40 kilometres in diameter. The energy released on impact would dwarf the detonation of all nuclear weapons on Earth combined, he said. The impact caused what's known as the "KT Extinction Event," a combination of blast effects that killed off 70 per cent of life on the planet 65 million years ago. Other researchers say more study is needed.

This will rattle some cages. Common consensus is that the Chicxulub crater off the Yucatan peninsula is the impact point for the KT extinction event. Others still argue that the dinosaurs were in steep decline even before either of these impacts took place.

----------------
Now playing: The Alan Parsons Project - I Wouldn't Want to Be Like You (Backing Track Rough Mix)
via FoxyTunes

Extinction in the Oceans

A news article that appeared on Yahoo News has implicated a huge volcanic eruption 260 million years ago in the devastation of life in the oceans:

The researchers were able to pinpoint the exact timing of the massive eruption thanks to a layer of fossilized rock which showed mass extinction of different life forms -- clearly linking the volcanic blasts to a major environmental catastrophe.

"The abrupt extinction of marine life we can clearly see in the fossil record firmly links giant volcanic eruptions with global environmental catastrophe," said Paul Wignall, a professor and palaeontologist at the University of Leeds, who was the lead author of the research paper in the May 29 edition of Science.

The eruption in southwest China unleashed about a half million cubic kilometers of lava, covering an area five times the size of Wales, according to the research by scientists at the British university.

Although the news of the extinction is new, the existence of this volcano is not. Geologic maps dating from the 1960s clearly showed the existence of a massive cone in central-west China. I remember looking at them and thinking "dang, that's a huge volcano."

Neandertals and Climate Change

It is now being suggested that Neandertals died out during a marked shift in the earth's climate, specifically the Iberian peninsula. What makes this climate shift different from those that preceded it is that modern humans were on the landscape and could out-compete the Neandertals, so the story goes. It is clear that there was selection for modern genes and that by 25 000 years ago, Neandertals were a thing of the past but I am still with the hybridization crowd.