Scientists used evolutionary theory to figure out where
to find the bones of this fishibian.
Lately I have been reading Jerry Coyne's Why Evolution is True. And so far it is a fascinating read.

What is so great about this book for a scientist is that it gives the big picture on evolution. This sort of thing can be hard to get sometimes because we scientists are so specialized. As I like to tell people, I worked on a single amino acid of a single human protein for my postdoctoral project. For three years.

Coyne's book synthesizes genetics, anatomy, biogeography, physiology, paleontology, geology, and lots of other "ologies" to show how strong the case is for evolution. This is great for me because, of course, I tend to focus on genetics and molecular biology and spend less time on the other fields. Which means I miss important, subtle nuances to some big findings.

For example, I had heard about the fossil of Tiktaalik roseae that was found in 2004 that linked fish to amphibians. This was a huge deal because the animal that the bones came from had characteristics of both fish and amphibians. And it appeared in the fossil record at the right time to be a transitional animal between the two.

What I hadn't fully appreciated was that the scientists decided to look where they did based on how old they thought the fossil should be. In other words, they were able to use the theory of evolution to predict where to find the fossil they were looking for.

They knew from previous fossil finds that something like Tiktaalik roseae would have appeared between 360 and 390 million years ago. The scientists also knew from previous research that the beast would have been in freshwater. So they got out a geological map and looked for places that met these criteria. They settled on Ellesmere Island in Canada and after five years, they found this marvelous fossil.

This is important for a lot of reasons. One is that it obviously tells us a lot about how vertebrates emerged onto dry land. Another is that it provides further validation of geological dating methods. They had to rely on these methods to know where to look for the fossil and the methods worked.

This find is also important because it is based on a prediction made by evolutionary theory. Around 390 million years ago, the only vertebrates were fish. By 360 million years ago, there were four-footed vertebrates on land. So the scientists looked in a place that was 375 million years old.

Scientists used evolution to make a testable prediction that turned out to be true. And evolution came through with flying colors like any good scientific theory should.

This year marks the 200th birthday of Charles Darwin – and the 150th anniversary of his landmark work, "On the Origin of Species". One of the iconic fossils that supports Darwin's theory of evolution is called the Archaeopteryx and it was recently flown out to Stanford University for an unusual test. Scientists are bombarding this dino-bird with high-tech gadgetry to unlock even more information about how we came to be here.

There are dozens of events celebrating Darwin this month. You can also join QUEST at one of them. On February 26th, QUEST will be screening our half-hour documentary, "Chasing Beetles, Finding Darwin" at the California Academy of Sciences. We'll be joined by two scientists featured in the story. You can get more info or buy tickets here.

Listen to the Investigating Darwin's Legacy radio report online.

Methane concentrations revealing a plume in Mars' northern
hemisphere during its summer season. Credit: NASAMethane on Mars? Really? What does that mean?

We've known about the existence of methane gas on Mars for several years now, from independent observations.  Further observations have led to the detection of "plumes" or clouds of methane gas apparently emanating from specific locations on Mars.  One plume is estimated to contain 19,000 metric tons of the stuff.

Why is this exciting news? If you know anything about the source of most of Earth's atmospheric methane gas, you already know the answer:  possible life.  Not, I should say, necessarily life on Mars, but maybe a strong piece of evidence in that direction.

On Earth, methane (CH₄) is produced by living organisms—mostly by the activity of microbes, but some by the digestive processes in larger organisms (yes, like humans, and cows).  Methane is the major constituent of natural gas, which fuels gas powered ovens and heaters in homes, as well as natural gas power plants.  Methane is also produced by decaying organic matter—that's where "swamp gas" comes from.

On Mars, methane gas cannot exist for long in the atmosphere; it is relatively quickly broken down by solar radiation.  So, the methane detected in Mars' atmosphere must be replenished by something, continually.

So the big question right now is, where is the methane coming from? Under the surface of Mars, almost certainly.  By biological processes—life—underground? Could be.  By non-biological means? Could be, too; methane can be produced through inorganic chemical processes.  We don't know yet.  The next step in finding out more will be the Mars Science Laboratory, a large rover scheduled to be launched to Mars sometime in the near future.

In one form or another, humans have been trying to see, or find, life on Mars for a long time.  Percival Lowell squinted at Mars' small, blurry disk through his 24-inch telescope in Flagstaff, and perceived markings he saw to be vast canal complexes, ostensibly built by a desert Martian civilization thirsty for water harvested from their planet's polar ice caps. This led to much of the science fiction relating to life on Mars in the 20^th Century.

Earth-bound telescopes noted seasonal changes in Mars' color and brightness, and some attributed this to possible seasonal growth of Martian vegetation—though it was later found that these variations were the effects of seasonal planet-wide dust storms.

The Viking landers' primary mission in the 1970's was to search for life.  They didn't find any by scratching around Mars' surface and testing the soils there.

The 1990's saw the controversy over microscopic structures in meteorites found on Earth but determined to have originated on Mars.  Some argued that these structures were fossils of Martian microbes that lived on Mars long ago.  Whether these findings were in fact fossils and not just geologic structures was never conclusive.

The determination that liquid water once flowed on the surface of Mars, and still exists under its surface at least as ice, is pretty much scientific fact today.  Evidence of past liquid flows have been imaged and mapped from space, and the Phoenix lander found water ice in the north polar regions last year.  And there's the rover Opportunity that has confirmed gray hematite, a mineral that forms in the presence of water.

It's almost certain that there are no Martian cows grazing the rusty desert plains out there.  But there seems to be a lot of evidence for the possibility that something is going on below Mars' surface—perhaps the presence of liquid water, perhaps the presence of some form of life.  We don't know yet, but it sure feels like we're onto something here….

It's entirely possible to spend years living in the Bay Area and never encounter a California Newt. This tiny amphibian spends most of its time living in burrows and holes. But once year, the newts make an epic migration (at least for them) to nearby ponds for mating season. It's incredible to see dozens of these animals making their slow, deliberate pilgrimage through the grass and underbrush.

That was one of the things we wanted to document when we began our exploration of Briones Regional Park, just east of Berkeley. This park is a favorite spot for locals, but is also home to some amazing wildlife. With the help of East Bay Regional Parks naturalist Meg Platt, we put together a science hike where you can see some of the amazing things the park has to offer. But you'll also notice on the map that we didn't pinpoint exactly where the newts live.

As Meg described, this is a fragile species and thanks to Parks District's work, the newts are able to thrive in Briones and several other East Bay parks. But it's important for hikers and park users to give this species plenty of space, especially during mating season. Make sure to keep dogs out of the park's ponds. Luckily, the East Bay Regional Parks district puts together programs for the public so everyone can safely discover this amazing species.

Check out the interactive map of the Briones exploration online, and watch our audio slide show about California Newts.

Lauren Sommer is an Associate Media Producer for QUEST.

A wishbone from a theropod and a turkey.This week, many of us celebrated one of the most American of holidays: Thanksgiving. Following tradition, most of us probably had a bite or two of turkey — if you were one of the fortunate to get your hands dirty, you may have used this New York Times video as a guide.

What you may not know is that we can find homologies of many birds parts — thigh bones, arm hones, and even wishbones — in our own skeleton, and it's not happenstance. The ultimate reason for this similarity is ancestry: birds, mammals and all other tetrapods (four-legged, air-breathing vertebrates) share a common ancestor, over 300 million years old. And, as the descendents, we all exhibit the same basic body plan, with additional anatomical refinements specific to each evolutionary history. Whether a tetrapod's arm is a fin, a wing or a limb throwing a baseball, a common structure is shared among them because of their evolutionary past.

Back to turkeys: in your holiday meal, you may have come across a very particular y-shaped bone: the wishbone. (The one from my turkey is drying on the counter above the kitchen sink). Humans actually have homologues of wishbones, but we don't call them that — they're our collarbones, or clavicles. These bones are long and slender, and they form a key part of complex of bones and muscles that allow us to move our arms. Living birds are unique among tetrapods in having clavicles that are fused together into the y-shaped structure called a furcula, and it plays a key roles in allowing birds to fly. Furculae stiffen the thoracic skeleton, and, in conjunction with a keeled breastbone (or sternum), they provide key muscle anchors for the unique flight stroke of the bird arm.

So, how did two bones get fused into one? Birds are descended from one particular line of dinosaurs called theropods, which includes dinosaurs like T. rex or Velociraptor. Over the last 20 years, paleontologists have assembled a detailed picture of the family tree, or phylogeny, of these animals, showing the exact anatomical changes that occurred along the lineage of theropods to living birds. The changes in the furcula plays a key role in this evolutionary sequence: it turns out that relatives of T. rex and many other theropods had fused furculae, but clearly these animals did not use the fused furcula to fly. Some paleontologists have suggested that fused furculae in theropods increased the mobility of the forelimbs. Then, as birds evolved flight, a fused furcula turned out to be wonderfully useful as a brace for a flapping limb.

Evolution often works in this manner: recruiting old structures to use in a new context, and many examples of such improvisation have been shown in the fossil record. Together, phylogeny and the fossil record reveal more about evolution that might not have been apparent when you were first biting into that savory chunk of turkey meat. To check find out more about your holiday dinosaur, check out this link too.

Nick Pyenson is a PhD candidate at the University of California, Berkeley, in the department of integrative biology and the museum of paleontology.

latitude: 37.7819, longitude: -122.286