Saturday Science: Boom!

A fairly interesting article on a recent find at the K/T boundary -- which is when the dinosaurs were wiped out:

If, on a certain evening about sixty-­six million years ago, you had stood somewhere in North America and looked up at the sky, you would have soon made out what appeared to be a star. If you watched for an hour or two, the star would have seemed to grow in brightness, although it barely moved. That’s because it was not a star but an asteroid, and it was headed directly for Earth at about forty-five thousand miles an hour. Sixty hours later, the asteroid hit. The air in front was compressed and violently heated, and it blasted a hole through the atmosphere, generating a supersonic shock wave. The asteroid struck a shallow sea where the Yucatán peninsula is today. In that moment, the Cretaceous period ended and the Paleogene period began.

The description of the events immediately following the impact is breathtaking. It's a wonder anything survived.

Saturday Science: Fossils From Way Down Under

Photo:  University of Queensland

As far under as you can get: Antarctica, to be exact.

"It's a very hard place to work, but it's an even harder place to get to," Steve Salisbury, a researcher at the University of Queensland and one of the scientists on the expedition, says in a release.

Salisbury was one of 12 scientists from the U.S., Australia and South Africa that ventured south on a fossil hunting mission to James Ross Island, located on the Antarctic Peninsula. Over five weeks, the team camped on Vega island, hiking over six miles a day to to reach their main hunting grounds where they systematically sorted through rocks.

The scientists retrieved over a ton of fossils from ancient marine creatures, dinosaurs and birds that lived during the late Cretaceous Period. The massive stash could take years for them to catalog and study. For now, they say, the fossils will make their way to Chile and then Pittsburgh's Carnegie Museum of Natural History.

In case you're thinking "How weird! How could dinosaurs live in Antarctica?" keep in mind that Antarctica wasn't always where it is now, and that at various times, the earth has been much warmer than it is now. So it only stands to reason that there would be fossils there; the only real problem is getting at them. It's not what you call ideal working conditions.

There's video at the link of an interview with Salisbury that gives an idea of what it was like just getting ready to work.

Saturday Science: I'm Not Making This Up

An artist's colour reconstruction of Hallucigenia sparsa is shown in this image released to Reuters on June 23, 2015. REUTERS/Danielle Dufault/Handout

This is not an illustration for a science-fiction story. This creature, Hallucigenia sparsa, actually lived -- 508 million years ago. And after a fair amount (ahem) of research, scientists have finally figured out which end was which:

Hallucigenia, 0.4 to 2.2 inches long (10-55 mm), possessed seven pairs of nail-like spines protruding from its back, with an equal number of pairs of long, flimsy legs underneath tipped with claws. There were three pairs of skinny tentacles toward the head, perhaps used to process food or as antennae.

Hallucigenia has long baffled scientists. In the 1970s, it was thought its back spikes were legs, its legs were tentacles along its back and its head was its tail.

Keep in mind that we're dealing with a period in which Nature, so to speak, was being wildly experimental. Anything was possible -- until evolution cast the deciding vote. In this case, we're talking about an example of a group known as velvet worms, which are still around. As a group. Just not this particular one.

The universe is a strange and wonderful place.

Saturday Science: Reaching Critical Mass

No, it's not about atomic bombs. It's about the evolution of birds:

The early stages of the process through which birds evolved from dinosaurs was slow and gradual, and there was no single “missing link” separating the two different types of creatures, according to research published in Thursday’s edition of the journal Current Biology.

Lead author Dr. Stephen Brusatte, a paleontologist at the University of Edinburgh in Scotland, and his colleagues analyzed the anatomical make-up of more than 850 body features in 150 extinct species in order to map the evolutionary journey from meat-eating dinosaurs to ancient birds. Based on the fossil records, they found that the emergence of birds took place bit-by-bit over the course of 150 million years.

That's something I've noticed in reading about dinosaurs -- as we've discovered more about them, it's become apparent that things like feathers were around long before there were birds to wear them. It makes sense that other characteristics would pop up along the line until you had something approaching bird-hood.

And then things started happening really fast:

“There was no moment in time when a dinosaur became a bird, and there is no single missing link between them,” Dr. Brusatte said in a statement. “What we think of as the classic bird skeleton was pieced together gradually over tens of millions of years. Once it came together fully, it unlocked great evolutionary potential that allowed birds to evolve at a super-charged rate.”

And so we now have everything from sparrows to ostriches.

I have to admit of a certain fondness for sparrows. They're just always so busy.

Saturday Science: About That Asteroid

A fairly entertaining video on all (or at least most) of the things that actually caused the extinction of the dinosaurs. Hint: the asteroid was the last straw.

And you may have noticed, that was not the only mass extinction -- there has been a whole series of them, including those known as the Big Five, when over half of all species were wiped out. There's actually an earlier one than the first described in that list, the Great Oxygenation Event, marked by the introduction of free oxygen into the atmosphere, which proved toxic to the anaerobic organisms that were the first life on earth. That one was several billion years ago.

And if you were paying attention to the articles at the links, you will have noted that all of these events involved climate change.

A lot of people are saying that we're heading into the sixth mass extinction. But it's not climate change that's driving it -- it looks like that will be, as it has been in the past, the last straw.

In a new review of scientific literature and analysis of data published in Science, an international team of scientists cautions that the loss and decline of animals is contributing to what appears to be the early days of the planet's sixth mass biological extinction event.

Since 1500, more than 320 terrestrial vertebrates have become extinct. Populations of the remaining species show a 25 percent average decline in abundance. The situation is similarly dire for invertebrate animal life.

The article cites a number of possible reasons, but it all boils down to one thing: the rise of agriculture and the concomitant increase in human population.

Saturday Science: About Those Surviving Dinosaurs

Well, we call them "birds" these days. It seems that, unlike everything else, they kept getting smaller.

Our research shows that the ancestors of birds were the only lineage of dinosaurs to continually shrink in size for an extended period of time (at least 50 million years, and perhaps twice as long). They were also the fastest-evolving lineage of dinosaurs.

Oh, and if you're wondering about feathers, well -- they were pretty common among dinosaurs:

We now know that many bipedal, meat-eating dinosaurs (theropods) – including relatives of T. rex and Velociraptor – were adorned with a variety of feathers. They were preserved in such detail in fine volcanic ash that often even their colours can be reconstructed. Plumage might have even been present in all dinosaurs.

The article is worth reading, although I found it a little dry. But there's a video for those with short attention spans:

Saturday Science: Lotsa Goodies, Cambrian Variety

Paleontologist have struck it rich. I don't know if you've heard of the Burgess Shale, but it's legendary as one of the richest find of Csmbrian fossils ever. Now there's a find that may be even richer:

"Nowhere do we have a better view of exactly what the Cambrian looked like and its relationship to the environment than in the Burgess Shale," [Robert} Gaines told Live Science's Our Amazing Planet.

The new site is also in the Burgess Shale formation, and seems to rival the 1909 original in fossil diversity and preservation, researchers report today (Feb. 11) in the journal Nature Communications. In just two weeks, the research team collected more than 3,000 fossils representing 55 species. Fifteen of these species are new to science. [Gallery: Amazing Cambrian Fossils from Canada's Marble Canyon]

"The rate at which we are finding animals — many of which are new — is astonishing, and there is a high possibility that we'll eventually find more species here than at the original Yoho National Park site, and potentially more than from anywhere else in the world," said Jean-Bernard Caron, lead study author and an invertebrate paleontologist at the Royal Ontario Museum in Toronto.

Just one of the cuties they've found:

 A new arthropod species discovered at the Marble Canyon outcrop.
Credit: Jean-Bernard Caron

That's from the gallery -- click through and take a look -- the landscape is as impressive as the specimens.