07/25/14

Gangs of Feathered T-Rex


Packs of tyrannosaurs
Imagine, if you will, an early morning scene in the late Cretaceous. The air is quiet as the day warms. At the edge of a large forest a plain of ferns ripples in the light breeze (grass would not evolve for another 20 or so million years). Under the canopy of the ancient beeches and maples, there is movement. Nothing fast, just a hint. A flash of mottled colour against the background. A glint of light off an eye. A soft snuffling. A feather falls silently to the forest floor.

Among the nearby ferns, a pack of ceratopsians grazes, adults watching the woods carefully, nervously, herding the young towards the safety of the pack’s centre with prods of their heads, honking to get the young ones’ attention. They eat the flowers that dot the plain among the ferns and cycads, chew the horsetails that grow at the edge of the ponds and streams. A youngster sees a tasty patch of moss and, unnoticed, slips out between the elders to get it.

Suddenly the forest explodes. Leaves scatter and branches snap as the muscular forms crash through the cover and converge on the young triceratops, separated from the horned protection of the pack. Two large adults, a teenager and two younger tyrannosaurs running a well-coordinated hunt as they have done many times int he past. Their speed makes them a blur against the trees.

The ceratopsians bellow in fear and rage, and quickly form a circle, heads out, protecting the oldest and youngest within the centre. The pack of tyrannosaurs’ charge sounds like thunder, and they screech in anticipation as they race to surround the doomed youngster. They circle rapidly, darting to avoid the feeble attempts at defence from the surrounded dinosaur.

The herd can’t save it, and they move away, quickly, the outer ring still shuffling backwards to keep their ferocious, horned heads facing the danger. The tyrannosaur pack ignores the herd as it feeds, tearing off chunks of the living flesh as the youngster’s screams get fainter.

Their hunger slaked for the moment, the pack would soon retire to the forest to look for another easy target that might venture close by.

Triceratops vs tyrannosaur

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05/11/14

Confused Science


Confused In his book, The World in Six Songs, Daniel Levitin posutlates the ability to make or participate in music may have conferred an evolutionary advantage to early humans. It’s a reasonable hypothesis based on both archeological and anthropological evidence. And some paleontological finds, too.

We know from remains of bone flutes and other instruments, that humans made music at least 40,000 years ago. What that music was like, what role it played in primitive culture and society, what ceremonial or bonding purposes it had, will always be speculation (although we do know they likely used the pentatonic scale). We can only infer music’s roles from its uses in historic – i.e. since the invention of writing – civilizations, but we can never be sure what happened – and why – before the historical record.

When humans started singing, drumming, or making instruments to accompany themselves is simply something we will never know. Anything to suggest when is mere speculation. And even suggesting why is, too. We’re using post hoc analysis to infer purpose and reason.

We do know that group singing and dancing involves the release of certain neurochemicals like oxytocin, that can have powerful social-bonding effects on individuals, but we don’t know whether the particular chemistry is recent, ancient or even had the same effect on earlier cultures. However, given the relatively common and similar effects observed today, it’s another reasonable speculation that they occurred earlier within our evolution and helped humans bond, cooperate and accomplish group tasks.

And we do know that non-literate or non-technological societies – what few remain, such as those rare Amazonian tribes – use music and singing in social and cultural activities and rituals. Music and singing are as powerful in their cultures, in their daily lives, as sex and magic.*

(The co-development of music and civilization is fascinating, but apparently fragile. Music was mostly a communal activity, much more participatory, before the post-WWI development of communication technology. Today, thanks to the internet, digitalization and newer technologies, music is less a shared, bonding activity than it is a passive experience. Musicians – the people who create the experience – still create and shape public opinion and taste, but like alchemists and shamans, they are on the fringe of society.

There is a glimmer of hope that music may be returning to its communal, social roots with the recent growth in popularity of the ukulele and the resurgence of communal ukulele groups…)

Levitin – as brilliant as he is about neuroscience and music – seems confused about evolution and natural selection. And a few other sciences, as I’ll explain below.

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04/28/14

Seeing evolution in action


Peter and Rosemary GrantThe pop-science notion is that evolution takes a long time. Millennia, many millennia; even millions of years. But is that always true? Can one actually see and measure evolution in action? Can it happen in such a short time as to be recorded?

Peter and Rosemary Grant say they have. And it’s the subject of a new book they co-authored based on their research.

Their story was reported in the April 23 issue of the Princeton Alumni Weekly. It’s a terrific read if for nothing more than their 40-year tale of dedication, science and adventure on the isolated Daphne Major Island, one of the smaller islands of the Galapagos chain.

Forty years studying finches together, away from human company, away from the comforts of civilization. The small birds that first gave Charles Darwin insight into the mechanics of natural selection were their focus. And the Grants report they have seen that mechanism in action on the island.

Scientists previously had reported seeing the processes of natural selection among bacteria, honeycreepers, cichlid fish, and fruit flies. As Peter Grant puts it, “Until we began, it was well understood that agricultural pests and bacteria could evolve rapidly, but I doubt that many people thought that about big, vertebrate animals.”

The Grants believe that hybridization is an important force in the rise of new species, and think this applies, too, to human evolution. For a long time, for example, paleontologists believed that Neanderthals and “modern homo sapiens” did not interbreed when they came into contact in prehistoric times, but recent research indicates that about 20 percent of Neanderthal genes have been preserved in our species. “It’s almost been a hobbyhorse of ours,” Peter says. “We were saying, ‘I bet there has been gene exchange between the lineages of homo sapiens throughout their evolution.’”

The Grants’ new book is targeted at both lay readers and scientists familiar with their work, and broadly discusses their findings about natural selection, hybridization, population variation (why do some populations of birds vary more dramatically in beak size?), the potential vanishing of a species through interbreeding, and, of course, the potential origin of a new species — the Big Bird lineage. They also touch on global warming and its possible effect on Darwin’s finches. Most of all, the book is an affirmation of the importance of long-term fieldwork as a way of capturing the true dynamism of evolution.

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12/19/13

American belief in evolution is growing: poll


Alien SaintA new Harris poll released this month shows that Americans apparently are losing their belief in miracles and gaining it in science. The recent poll showed that American belief in evolution had risen to 47% from its previous poll level of 42%, in 2005.

True, it’s not an overwhelming increase, and it’s still less than half the population, but it is an improvement. Belief in creationism dropped 3% during that time, to 36%. Good news, of course, but don’t break out the champagne yet. There’s other data and it’s not all so good.

At the same time more Americans are believing in the science of evolution, American belief in many religious teachings is falling. Belief in miracles, heaven and others has dropped since the last poll:

  • 72% believe in miracles, down from 79 percent in 2005;
  • 68% believe in heaven, down from 75%;
  • 68% believe that Jesus is God or the Son of God, down from 72%;
  • 65% believes in the resurrection of Jesus Christ, down from 70%;
  • 64% believe in the survival of the soul after death, down from 69%;
  • 58% believe in the devil and hell, down from 62%;
  • 57% believe in the Virgin birth, down from 60%.

CNS News also tells us the poll shows:

  • Absolute certainty that there is a God is down vs. 10 years ago (54% vs. 66% in 2003).
  • Outside of specific religious samples, the groups most likely to be absolutely certain there is a God include blacks (70%), Republicans (65%), older Americans (62%), Baby Boomers (60%), Southerners (61%) and Midwesterners (58%), and those with a high school education or less (60%).
  • There continues to be no consensus as to whether God is a man or a woman. Nearly 4 in 10 Americans (39%) think God is male, while only 1% of U.S. adults believe God is female. However, notable minorities believe God is neither male nor female (31%) or both male and female (10%).
  • 19 percent of Americans describe themselves are “very” religious, with an additional four in ten (40%) describing themselves as “somewhat” religious (down from 49% in 2007). Nearly one-fourth of Americans (23%) identify themselves as “not at all” religious – a figure that has nearly doubled since 2007, when it was at 12%.

The Harris Poll has some not-so-good news to report, as well. According to the pollsters, more Americans believe in ghosts, reincarnation and UFOs than in 2005:

  • Reincarnation: 25%, up 3%
  • Ghosts 42%, up 1%
  • UFOs 36%, up 1%

I’m not sure whether to blame this lapse in critical thinking on ‘reality” TV or the internet. Either way, it’s troubling.

Belief in witches is down to 5% to 25%, and belief in astrology remains unchanged at 29%. Belief in angels is down 6%, but still staggeringly high at 68%. Imaginary beings are losing followers, while pseudoscience still hangs in there. The good news, if one reads it thus, is that belief in the science of evolution is finally higher than the belief in witches, ghosts, UFOs, astrology, creationism and reincarnation. But not angels.

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10/23/13

Survival of the Fittest


Herbert SpencerCharles Darwin has long been associated with the phrase, “survival of the fittest.” For a century and a half people have used it to refer to their understanding of his explanation of how species evolved.

But it wasn’t his. And it has obscured the understanding of Darwin’s own theory.

It came from a contemporary, Herbert Spencer. Spencer was a contemporary of Darwin – an English polymath:  philosopher, biologist, anthropologist, sociologist, economist liberal political theorist, utilitarian – and, by some accounts, an early libertarian. His ideas came from people like Malthus and Adam Smith (read more about his philosophy here). Wikipedia tells us:

For many, the name of Herbert Spencer would be virtually synonymous with Social Darwinism, a social theory that applies the law of the survival of the fittest to society; humanitarian impulses had to be resisted as nothing should be allowed to interfere with nature’s laws, including the social struggle for existence. Spencer desired the elimination of the unfit through their failure to reproduce, rather than coercion or state intervention to initiate their physical annihilation.

He wrote his interpretation of Darwin’s ideas in an 1864 textbook of biology:

“This survival of the fittest, which I have here sought to express in mechanical terms, is that which Mr. Darwin has called ‘natural selection’, or the preservation of favoured races in the struggle for life.”

Spencer was really trying to apply Darwin’s ideas to his own ideas about economics, class struggle, competition and politics. He also believed in Lamarckism – the inheritance of attributes gained in one generation by the next – which has long since been discredited. But whether you agree with Spencer’s views, his reduction of Darwin’s theory to a convenient axiom did the theory an injustice.

In the public mind, Darwin’s ideas about natural selection were confusing and challenging. They became conflated with Spencer’s ideas and somehow the phrase stuck – the Victoria era equivalent of a bumper sticker phrase. It became wildly popular, and was soon applied to social and political phenomena, not simply biological.

It was so popular as a catch phrase that in the 1869  fifth edition of his book, On the Origin of Species, Darwin – unfortunately – added this line:

“But the expression often used by Mr. Herbert Spencer, of the Survival of the Fittest, is more accurate, and is sometimes equally convenient.”

The problem is really in how the word “fittest” is defined. Like its sister term, theory, it has both a common and a scientific meaning.*

Survival of the FittestFittest, in Darwin’s sense, doesn’t mean the biggest, best, toughest, strongest or even the most competitive. It’s not the macho concept of superiority. It isn’t about power, control or brute force.

It means the “best suited for the immediate environment.” It has also been described as a “property of the relationship between the organism and the environment.” That might be a different colour, smaller size, less active. Whatever offers the best opportunity to survive and breed. Having offspring is key.

It’s a far more subtle notion than commonly used. As Wikipedia says:

Modern evolutionary theory defines fitness not by how long an organism lives, but by how successful it is at reproducing. If an organism lives half as long as others of its species, but has twice as many offspring surviving to adulthood, its genes will become more common in the adult population of the next generation.

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09/17/13

The Cosmic Origins of Life


CometHere’s one to confound the creationist crowd: life may have begun as a result of organic molecules resulting from impacts by comets or meteorites. No supernatural foundation, no invisible hand guiding the process. Just random crashes, a little physics, some chemistry, a while lot of time, and voila: life.

But wait, there’s more…

How did these molecules go from static organic molecules to self-reproducing you ask? Ah, therein lies another tale… that of enzymes, the little engines of life. More randomness, more chemistry. No intelligent design.

Let’s start with the comets.

According to a recent article in Science Daily,

Scientists … from Imperial College London, the University of Kent and Lawrence Livermore National Laboratory discovered that when icy comets collide into a planet, amino acids can be produced. These essential building blocks are also produced if a rocky meteorite crashes into a planet with an icy surface.

The researchers suggest that this process provides another piece to the puzzle of how life was kick-started on Earth, after a period of time between 4.5 and 3.8 billion years ago when the planet had been bombarded by comets and meteorites.

The intrepid researchers fired projectiles at comet-like speeds into icy surfaces similar to what we know comets are made from.  They discovered that the shock wave slams simple molecules together into more complex forms. The heat from the impact  then transforms these more complex molecules into amino acids such as glycine and D-and L-alanine.

Dr Mark Price, co-author from the University of Kent, adds: “This process demonstrates a very simple mechanism whereby we can go from a mix of simple molecules, such as water and carbon-dioxide ice, to a more complicated molecule, such as an amino acid. This is the first step towards life. The next step is to work out how to go from an amino acid to even more complex molecules such as proteins.”

In a similar experiment, published in July,2013, scientists simulated an icy comet-like snowball using carbon dioxide, ammonia, methane, ethane and propane. They zapped it with high-energy electrons to “simulate the cosmic rays in space” and discovered that the result was “complex, organic compounds, specifically dipeptides, essential to life.”

Chemists from the University of California, Berkeley, and the University of Hawaii, Manoa, showed that conditions in space are capable of creating complex dipeptides – linked pairs of amino acids – that are essential building blocks shared by all living things. The discovery opens the door to the possibility that these molecules were brought to Earth aboard a comet or possibly meteorites, catalyzing the formation of proteins (polypeptides), enzymes and even more complex molecules, such as sugars, that are necessary for life.

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07/23/13

The colonization of land by life pushed back in time


Fossile lifeA recent story on Science Daily made me stop and read with fascination. It’s about the discovery of fossils that showed life colonized land more than two billion years ago. That’s a shocker, because all indicators are that the Earth was a hostile place, land was barren, and life was a lot simpler.

But apparently we underestimated the ability and tenacity of life. This gives us hope that life may exist on other planets or moons.

Mars, at least its surface, is unlikely to harbour life now, but may have in its water-rich past. We may find fossils. Europa, Jupiter’s ice-covered moon, may have life in the oceans under its surface. Finding out will be tough. Titan? A remote possibility. But these fossils give us new hope: life can survive in very hostile conditions.*

Conventional scientific wisdom has it that plants and other creatures have only lived on land for about 500 million years, and that landscapes of the early Earth were as barren as Mars. A new study, led by geologist Gregory J. Retallack of the University of Oregon, now has presented evidence for life on land that is four times as old — at 2.2 billion years ago and almost half way back to the inception of the planet.hat landscapes of the early Earth were as barren as Mars.

That raises several interesting ideas. First, what sort of life was it? The researchers don’t know for sure, but it’s a bit like slime mold or some lichen. It was tiny, but rather complex given its age and a promising candidate for the oldest known eukaryote. Sci-news notes:

Diskagma buttonii are very small – about 0.3 – 1.8 mm long. They most resemble modern soil organisms called Geosiphon, a fungus with a central cavity filled with symbiotic cyanobacteria.

It was something not quite animal or plant – something simple. But not that simple: they appear to have had symbiotic cyanobacteria in their interiors. Cyanobacteria appeared about 3 billion years ago, and started photosynthesizing (with water as a reducing agent) and making oxygen between then and about 2.6 billion years ago (life itself first showed up about 3.5 billion years ago but some estimates push it much earlier, to 4.3 billion).**

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