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Posts Tagged ‘Evolution’

Trove of Dinosaur Feathers Found in Canadian Amber

15 Sep
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Discovery

An extraordinary collection of ancient feather fragments preserved in amber has opened a window into a lost world, one that now appears populated by dinosaurs covered in plumage as rich and varied as that of modern birds.

The feathers date to the end of the Cretaceous, about 85 to 70 million years ago. At that time, the forerunners of birds were well on their way to taking wing; dinosaurs like Epidexipteryx and Limosaurus, discovered in China in the last decade and dating to approximately 160 million years ago, possess relatively bird-like bone structures and hints of what might have been feathers.

Those hints have been interpreted -- and given life in eye-popping artist renditions -- as feathers, an interpretation that was plausible but still inconclusive.

But the latest fossils, found in Alberta and described Sept. 16 in Science, leave little doubt. The age of dinosaurs was a feathery one.

"These lovely specimens of significantly older, smaller dinosaurs from China have got some sort of covering about them. But you can't tell if it's hair or feathers because the fossils have undergone the ravages of time," said paleontologist Alex Wolfe of the University of Alberta, a co-author of the new study. "Those fossils don't preserve the kind of detail that we have in amber, which doesn't fossilize but entombs an object."

On the following pages, Wired.com looks at the new trove of feathers.

Above:

Feathers in Amber

Image: McKellar et al./Science

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See Also:

Citations: “A Diverse Assemblage of Late Cretaceous Dinosaur and Bird Feathers from Canadian Amber.” By Ryan C. McKellar, Brian D. E. Chatterton, Alexander P. Wolfe, Philip J. Currie. Science, Vol. 333 Issue 6049, September 16, 2011.

“Fossilized Feathers.” By Mark A. Norell. Science, Vol. 333 Issue 6049, September 16, 2011.

 
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How to see people, not just our reactions to them

13 Sep

When we encounter someone, usually the mind automatically slots the person into a category: man, woman, your friend Tom, the kid next door, etc. Watch this happen in your own mind as you meet or talk with a co-worker, salesclerk, or family member.

In effect, the mind summarizes and simplifies tons of details into a single thing – a human thing to be sure, but one with an umbrella label that makes it easy to know how to act. For example: “Oh, that’s my boss (or mother-in-law, or boyfriend, or traffic cop, or waiter) . . . and now I know what to do. Good.”

This labeling process is fast, efficient, and gets to the essentials. As our ancestors evolved, rapid sorting of friend or foe was very useful. For example, if you’re a mouse, as soon as you smell something in the “cat” category, that’s all you need to know: freeze or run like crazy!

On the other hand, categorizing has lots of problems. It fixes attention on surface features of the person’s body, such as age, gender, attractiveness, or role. It leads to objectifying others (e.g., “pretty woman,” “authority figure”) rather than respecting their humanity. It tricks us into thinking that a person comprised of changing complexities is a static unified entity. It’s easier to feel threatened by someone you’ve labeled as this or that. And categorizing is the start of the slippery slope toward “us” and “them,” prejudice, and discrimination.

Flip it around, too: what’s it like for you when you can tell that another person has slotted you into some category? In effect, they’ve thingified you, turned you into a kind of “it” to be managed or used or dismissed, and lost sight of you as a “thou.” What’s this feel like? Personally, I don’t like it much. Of course, it’s a two-way street: if we don’t like it when it’s done to us, that’s a good reason not to do it to others.

The practice I’m about to describe can get abstract or intellectual, so try to bring it down to earth and close to your experience.

When you encounter or talk with someone, instead of reacting to what their body looks like or is doing or what category it falls into:

  • Be aware of the many things they are, such as: son, brother, father, uncle, schoolteacher, agnostic, retired, American, fisherman, politically conservative, cancer survivor, friendly, smart, donor to the YMCA, reader of detective novels, etc. etc.
  • Recognize some of the many thoughts, feelings, and reactions swirling around in the mind of the other person. Knowing the complexity of your own mind, try to imagine some of the many bubbling-up contents in their stream of consciousness.
  • Being aware of your own changes – alert one moment and sleepy another, nervous now and calm later – see changes happening in the other person.
  • Feeling how things land on you, tune into the sense of things landing on the other person. There is an experiencing of things over there – pleasure and pain, ease and stress, joy and sorrow – just like there is in you. This inherent subjectivity to experience, this quality of be-ing, underlies and transcends any particular attribute, identity, or role a person might have.
  • Knowing that there is more to you than any label could ever encompass, and that there is a mystery at the heart of you – perhaps a sacred one at that – offer the other person the gift of knowing this about them as well.

At first, try this practice with someone who is neutral to you, that you don’t know well, like another driver in traffic or a person in line with you at the deli. Then try it both with people who are close to you – such as a friend, family member, or mate – and with people who are challenging for you, such as a critical relative, intimidating boss, or rebellious teenager.

The more significant the relationship, the more it helps to see beings, not bodies.

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Bird Flight Might Have Started With Legs, Not Wings

18 Aug

To take flight, first strengthen your legs: It sounds like a self-help proverb, but it could explain how birds first took wing.

Until now, most explanations of the evolution of flight have assumed that going airborne was an end in itself, driven by the need of some early dinosaur to glide down from trees or up off the ground.

But flight could have instead been an incidental benefit of beefier muscles needed to compensate for losing a heat-generating protein.

“Flight is seen as the hallmark of bird evolution,” said developmental biologist Stuart Newman of the New York Medical College. “But you can make the argument that the particular form bird skeletons took that opened the way for flight was a side effect.”

Newman’s research shows that all birds and reptiles lack a single gene that codes for a protein called UCP1 or, with a nod to its function, thermogenin. It’s an essential part of the metabolic reaction that burns brown fat, helping bodies self-regulate internal temperature and generate heat without shivering.

Thermogenin’s absence from birds and reptiles hints at its loss in some early common ancestor, with the thermogenin-retaining relative later giving rise to mammals. But whereas reptiles became cold-blooded, basking in sunshine when needed, birds stayed warm-blooded.

Image: Markiza/Flickr

As Newman describes in a September Bioessays paper, the key to their warmth is muscles. Muscles are powerful generators of heat, which is a byproduct of the chemical reaction that makes them contract. Bird muscles also have further heat-generating adaptations. And birds are, in a word, jacked.

In ounce-for-ounce comparison, mammals and reptiles are scrawny weaklings next to birds. And it’s not just avian breast muscles that are pumped, as would be expected in flyers, but their legs too.

“My hypothesis is that birds basically salvaged their existence by developing very large skeletal muscles,” said Newman.

Once heavily muscled, he believes proto-birds would naturally have gravitated towards bipedalism, which isn’t a particularly challenging transition. Indeed, walking on two legs was widespread in dinosaurs.

Bipedality releases upper limbs, both literally and in evolutionary terms, allowing them to accumulate large mutations with relatively little risk. Combine that with powerful breast muscles, and wings would soon follow.

Testing Newman’s hypothesis may not be possible, as it would require comparing early bird and dinosaur skeletons and genes, and DNA is lost in the fossil record. But that flight could plausibly have been a fortunate side effect of some unrelated adaptation, rather than the original driver of bird development, is a useful evolutionary lesson.

Newman also suggests people at least reconsider the phenomenon of flightlessness in birds, which is generally portrayed in terms of loss.

“It’s almost universally accepted that all flightless birds come from flighted ancestors,” said Newman. “That might be true — but maybe it’s flying birds that have flightless ancestors. Maybe flightless birds were the leading edge.”

Top image: Lip Kee Yap/Flickr

See Also:

Citation:”Thermogenesis, muscle hyperplasia, and the origin of birds.” By Stuart Newman. Bioessays, Vol. 33 No. 9, September 2011.

 
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Gibbons defy their own evolution to jump as high as they can [Monkey News]

10 Aug
Most jumping animals - such as frogs and grasshoppers - have some powerful adaptations that basically make their legs into giant springs. But our ape cousins manage to leap insane distances through sheer force of will, without any helpful adaptations. More »
 
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What is the point of pruney fingers?

28 Jun

The common wisdom is that your fingers wrinkle when they’re wet because they absorb water. But Mark Changizi thinks there’s more to it than that. According to him, pruney fingers are an adaptation to help humans, and probably other primates, get a better grip during wet conditions. They act like the rain treads on tyres. Mark lays out his hypothesis in a wonderful paper that I wrote up as a news story for Nature News.

Here’s the start; click through for the whole thing.

The wrinkles that develop on wet fingers could be an adaptation to give us better grip in slippery conditions, the latest theory suggests.

The hypothesis, from Mark Changizi, an evolutionary neurobiologist at 2AI Labs in Boise, Idaho, and his colleagues goes against the common belief that fingers turn prune-like simply because they absorb water.

Changizi thinks that the wrinkles act like rain treads on tyres. They create channels that allow water to drain away as we press our fingertips on to wet surfaces. This allows the fingers to make greater contact with a wet surface, giving them a better grip.

Scientists have known ...

 
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The first sign that humans are on the verge of evolving into another species [Evolution]

28 Apr
A scientist who studies the small, silver elephantfish may have stumbled on the key to speciation, the process that allows one species to evolve into two or more. And it's all about developing new sensory perceptions. More »
 
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Meet the weird bird that’s half-chicken, half-turkey [Biology]

16 Mar
This is the Transylvanian naked neck chicken, popularly known as the "churkey" because it appears to have the body of a chicken and the head of a turkey. And this mysterious mutation could actually help feed the world. More »
 
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How did humans really evolve? [Io9 Backgrounder]

04 Mar
Almost two million years ago, a band of brave explorers left their families behind in their warm, tropical home and sought refuge in northern lands. Armed with sharp stone tools and their wits, they followed the coast as far north as they could, then began to veer east, settling on the sunny, fertile shores of an inland sea that today we call the Mediterranean. Their children spread further north and east, and a million years later they had established settlements along the coasts of today's Europe, England, and China. More »
 
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600 million-year-old fossils reveal catastrophic oxygen loss on ancient Earth [Evolution]

17 Feb
635 million years ago, almost the entire planet was a frozen ball of ice. And yet mere tens of millions of years later a population explosion happened deep underwater in South China, preceding the better-known Cambrian explosion by a significant time period. In these oxygen-free waters, more than 3,000 fossils of 15 species of seaweeds and worms lived briefly, and then all died suddenly. More »
 
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We may be even more alone in the universe than we thought [Evolution]

22 Oct
Two scientists propose that the jump from bacteria to complex life might be much riskier than previously imagined. Even on planets with earthlike conditions, plant and animal life would therefore be incredibly rare. More »
 
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