Placeholder Image

字幕列表 影片播放

  • Hidden inside this unassuming piece of limestone are the remnants of a creature that reveals

  • an extraordinary link between the age of dinosaurs and the present day.

  • Meet the wonderchicken.

  • - All of a sudden we saw this incredible skull staring out at us, once we caught our breath

  • and actually took a close look we realized that some structures of the skull, were very

  • similar to what you see in living chicken-like birds.

  • And so the name "wonderchicken" just materialized then and there.

  • The wonderchicken isn't just a well-preserved fossil; it's also a missing piece to the

  • puzzle of how modern birds came to be.

  • And this discovery might just change everything we thought we knew about their dino-heritage.

  • Again.

  • It all starts some 66 million years ago, when we think a meteorite or comet hit Earth and

  • wiped out the dinosaurs, bringing an end to the Cretaceous period.

  • That moment in time is now permanently marked in our geological record by a thin layer of

  • rock referred to as the K-T boundary.

  • - And within that clay you see a geochemical signature of a giant space rock hitting the

  • earth.

  • We have scant fossil evidence of birds from the Cretaceous period (you know, around the

  • time a giant space rock hit the Earth), which is why it's incredible to think that when

  • an amateur fossil hunter picked up this hunk of rock near the border of Netherlands and

  • Belgium, it sat unexamined in the back of a Dutch museum for twenty years.

  • But this year, Daniel and his team used Computed Tomography, a kind of x-ray sampling that

  • rotates around a sample to create cross-sectional, 3D images without damaging it, to take a more

  • detailed look.

  • - It was amazing, right at the outset we discovered that these not-very-pretty fossils

  • were actually much more important than they initially appeared.

  • So, what can the wonderchicken's skull tell us about the era of the asteroid and the origin

  • of pigeonsand other modern birds?

  • The first clue is that frontal bone in pink.

  • Equivalent to the forehead bone in you and me, this bone's hourglass shape suggests a

  • similarity in form, and maybe function, to modern-day ducks.

  • And that yellow bone connected to it is the nasal bone.

  • - The shape of the nasal bones are very interesting because their general profile and architecture

  • are very similar to what we see in living relatives of chickens.

  • And, in the turkey skull, if you can see, this bone here bounding the back of the nostril

  • is the nasal.

  • The general shape and architecture is very similar.

  • Finally, the dead ringer is the bone in red, called the premaxilla.

  • - The fact that the beak is very prominent and it's composed entirely of the premaxilla

  • tells us that yes, this is a modern bird.

  • It's been thought that the birds that exist today descended from early ancestors that

  • somehow managed to survive the Cretaceous-Tertiary extinction event.

  • But up until now, we hadn't found much clear evidence that modern birds and dinosaurs

  • like T. rex and Triceratops coexisted.

  • - The fact that we have a modern bird from just before this asteroid struck the earth

  • and wiped out the giant dinosaurs tells us that the earliest stages of modern bird evolutionary

  • history overlapped with the very final stages of the giant dinosaurs occupying the Earth.

  • So how did this little guy survive the mass extinction, while his enormous compatriots

  • were wiped out?

  • Well, we don't quite know for sure.

  • But it could be that the wonderchicken's small size saved its life.

  • This phenomenon is called the Lilliput Effect, which states that smaller-bodied species which

  • have lower total metabolic requirements are more likely to survive harsh conditions.

  • It also helps not to be too picky of an eater.

  • - If you think of a normal barnyard chicken, they will be generally pretty happy to eat

  • almost anything that's put in front of [them].

  • It has a generalist diet that may have made organisms perhaps better-suited to surviving

  • the mass extinction event than organisms with highly specialized diets.

  • But for Daniel and his team, this amazing discovery might just spin up more questions

  • than answers.

  • - What kind of birds actually managed to survive the extinction event that wiped out the giant

  • dinosaurs?

  • Were birds actually rare for a period of time after that extinction event?

  • We're hopeful that we'll be able to shed more light on these questions by finding new fossil

  • evidence of birds from these periods of time.

  • Fun fact: based on its long, narrow hind limbs, the scientists think that this wonderchicken

  • may have been a shorebird.

  • So, the researchers gave the new species the genus name "Asteriornis," after the Greek

  • goddess of falling stars, who transformed herself into a quail and threw herself into

  • the ocean to escape an amorous Zeus.

  • For more on dinosaur history, check out this episode here.

  • If you have any other prehistoric science you want us to cover, let us know in the comments

  • below.

  • Make sure to subscribe, and thanks for watching.

Hidden inside this unassuming piece of limestone are the remnants of a creature that reveals

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B2 中高級

迎接恐龍滅絕後倖存下來的 "神奇雞" (Meet the “Wonderchicken” that Survived the Dinosaur Extinction)

  • 9 1
    Summer 發佈於 2021 年 01 月 14 日
影片單字