Placeholder Image

字幕列表 影片播放

  • {♫Intro♫}

  • Amber is amazing stuff.

  • And not just because you can use it to make really cool necklaces or, a brontosaurus apparently...

  • The specimens found in amber can teach us a lot about evolution or even how diseases

  • like the plague spread.

  • That's because amber preserves organisms whole and essentially freezes them in time.

  • How does it happen?

  • Well, first, some poor plant or animal gets stuck in a glob of tree resin — a sticky,

  • thick substance a plant releases when it's damaged.

  • Then, when the resin hardens, the creature gets pretty much mummified.

  • Like, seriously.

  • The chemical composition of tree resin actually dehydrates organisms, and that stops the processes

  • that would otherwise break down their tissues.

  • Resin even has antiseptic and antimicrobial compounds that help prevent fungi from decomposing

  • things.

  • This means stuff that normally wouldn't fossilize welllike plants and soft animal

  • tissuecan be preserved in amber.

  • And the specimens we've found in it so far range from amazing to downright bizarre.

  • So, without further ado, here are six of the coolest things we've found trapped in amber.

  • First, check out the leaves of this carnivorous plant, which were described in a 2015 paper

  • in the Proceedings of the National Academy of Sciences.

  • They're 35 million years old, and they come from a kind of ancient Roridulid plant — a

  • genus of evergreen, insect-trapping shrubs.

  • Scientists figured this out because the leaves have features that are really similar to modern

  • roridula plants found in South Africa.

  • Like, for one, they're long, narrow, and tapered.

  • They're also covered in two kinds of hair-like structures called trichomes.

  • One kind is stiffer and not sticky, and the other comes in different lengths and secretes

  • a kind of glue.

  • Those are the structures that trap and immobilize insects, which is what makes these plants

  • carnivorous.

  • Except, roridulids like this ancient specimen also seem to have a problem: Once they've

  • caught a meal with their sticky trichomes, they can't actually break it down on their

  • own.

  • They just don't have the digestive enzymes for it.

  • But, they've made do.

  • Instead of evolving their own enzymes, they rely on capsid bugs to do the job for them.

  • The bugs feed on the trapped organisms and then, the plant feasts on the capsid's poop.

  • Delightful, I love it!

  • Seeing something like this trapped in amber is always cool, because plant leaves generally

  • don't fossilize well.

  • But this specimen also told scientists something about the climate this plant lived in.

  • Before this fossil was found, scientists thought roridulids originated on Gondwanathe

  • supercontinent that split up to make Australia and part of South America, among other things.

  • But this bit of amber was found in a mine near Kaliningrad, Russia, meaning the plants

  • might have been in the Northern Hemisphere for a while, too.

  • Since roridula plants don't do well in the cold, that suggests the climate in Russia

  • some thirty-five million years ago was probably warmer than it is today.

  • Which seems like a lot to learn from one piece of old tree resin.

  • In 2011, scientists found 11 early forms of feathers, called protofeathers, hiding in

  • amber specimens from a museum and a university in Canada.

  • The protofeathers were from the Late Cretaceous period, around a hundred to 66 million years

  • ago.

  • And that was really convenient, because most of the feathers found before then were from

  • much earlier in historyabout 146 - 100 million years ago.

  • So scientists had a gap in their understanding of feather evolution.

  • That meant that, no matter what, these amber specimens were going to be useful.

  • But they turned out to be unbelievably helpful, because they contained four distinct stages

  • of feather evolution.

  • First, there were filament fibers which kind of look like hairsexcept, they're hollow

  • and don't have scales on their surface.

  • Researchers concluded these feathers were really similar to protofeathers on certain

  • non-avian dinosaurs, which helped keep the animals warm.

  • Next, the second stage was a bunch of these filaments branching out from a base.

  • Kind of like the protofeathers on some leaping dinosaurs.

  • These may have been decorative or added stiffness to their tails.

  • In the third stage, those tufts of filaments fused to form a central shaft and barbules.

  • These protofeathers actually looked a lot like feathers from modern-day grebes.

  • These diving birds have similar feathers on their bellies that help absorb water and make

  • them less buoyant so they can dive.

  • So scientists suggest these stage three feathers in amber may have been from Late Cretaceous

  • diving dinos.

  • Finally, the stage four feathers looked really similar to those on many modern day birds,

  • and could have been used for a range of functions, including flight.

  • The team thinks they did come from dinosaurs, though, based on the amber's age and the

  • similarities to other specimens.

  • Overall, these researchers pretty much hit the amber jackpot.

  • They had believed these four stages existed before, but with these discoveries, they essentially

  • got a timeline of how feathers evolved and how they were used during the Late Cretaceous.

  • In our last two examples, it was easy to see why the specimens were cool.

  • But sometimes, the most amazing part of these discoveries isn't as obvious.

  • That was the case in 2015, when scientists identified a new species of flea trapped in

  • amber.

  • The amber came from a mine in the mountains of the Dominican Republic, and the flea inside

  • was somewhere between15 and 45 million years old.

  • It looked pretty similar to modern fleas, except with a few extra appendages and features

  • like small eyes.

  • But the really cool thing was what scientists found in its mouth.

  • There, they discovered a group of bacteria with roughly the same size and shape as the

  • modern bacterium that caused the bubonic plague.

  • Yes, that plague.

  • Although the researchers couldn't confirm it, they think these microbes may be an ancestor

  • of the bacterium that caused the infamous fourteenth-century Black Death.

  • And if that's true, it means ancient plague strains may not have evolved as human parasites,

  • but as rodent ones.

  • That's partly because, well, humans weren't around 15 million years ago.

  • But also, the ancient bacteria were found in a glob of dried gunk near the flea's

  • esophaguswhich looks a lot like the glob that forms when today's fleas drink plague-infested

  • rat blood.

  • Scientists found fossilized rodent hairs at the site where the new flea was discovered,

  • too.

  • That suggests plagues might have wiped out way more animals than previously thoughtand

  • maybe they even contributed to extinctions.

  • In any case, this isn't something we would have figured out if that poor flea hadn't

  • got stuck in a bunch of tree resin.

  • So, Thanks for your sacrifice, flea.

  • Speaking of blood suckers, this next creature is a little less well-known.

  • It's called a bat fly.

  • There are about five hundred species of them, and they're like the vampires of the fly

  • world, because they feed entirely on bat blood.

  • Or maybe they're like the vampires of the vampires of the animal kingdom

  • Anyway.

  • In 2011, scientists found a 15 to 45 million-year-old bat fly stuck in amber from that same mountain

  • range in the Dominican Republic.

  • It's one of only two fossilized bat flies ever found, but as is the trend here, that

  • wasn't the most interesting thing about this.

  • It was the fact that, right there on the fly's midgut, were two eggs containing an ancient

  • form of bat-malaria.

  • And in the fly's salivary glands, there was also a spore-like stage of the parasite.

  • Now, to be clear, when I saybat-malaria,” I'm only talking about a malaria strain

  • that infects bats, not one that affects people.

  • But studying it is still important for keeping animals safe.

  • Researchers identified the pathogen as a bat-malaria ancestor because those spore-like stages resembled

  • a modern parasite, with its stubby shape and rounded edges.

  • Ultimately, this find was kind of surprising to scientists, because one: ancient bat-malaria,

  • trapped in amber!

  • That's a super unlikely, amazing discovery!

  • But also, before this, researchers thought that only flies from the Nycteribiidae genus

  • spread bat-malaria.

  • And this fly in amber was from the other, closely-related bat fly family, called Streblidae.

  • So this tiny specimen was the first evidence in both living or extinct bat flies that Streblidae

  • can also transmit malaria in bats.

  • Of course, just because no one's found a living example, doesn't mean that family

  • couldn't transmit bat-malaria today.

  • Which is important stuff to know if we're trying to keep animals healthy.

  • Amber really captures a moment in time, and that's especially true when it comes to

  • our next amber artifact.

  • This piece came from that same Caribbean mountain range with the flea and bat fly, and it held

  • a brand-new species of salamander.

  • Or at least, a brand new species to us.

  • Because in reality, this animal has been extinct for millions of years.

  • Scientists classified the new find as part of the plethodon salamander family, and it's

  • the only known salamander to ever exist in the Caribbean.

  • This animal shared a lot of features with modern plethodons, except for one: It didn't

  • have distinct toes like today's salamanders do.

  • Instead, it just kind of had little bumps on top of webbing.

  • That told scientists it probably didn't climb as well as its modern counterparts,

  • and it may have lived in small trees or flowering plants.

  • Still, like I said, there are no salamanders in the Caribbean today, and that made researchers

  • wonder how this species got there in the first place and where they all went.

  • Right now, they think this animal's ancestors may have waded over to the islands when they

  • were still connected to South America some forty to 60 million years ago.

  • Then, they stayed there and later evolved into this plethodon as the islands broke off.

  • Alternatively, they could have crossed a land bridge when sea levels were low, or even floated

  • over on a log at some point like some species of Caribbean frogs did.

  • However they got there, though, they certainly didn't stay.

  • The Caribbean salamanders probably all died out because the climate got cooler and drier

  • some 38 to 23 million years ago.

  • And that makes this salamanderand this specimen trapped in amberpretty darn

  • special.

  • Finally, the thing that inspired this entire episode, in 2019, scientists found the hindfoot

  • of a bird encased in 99 million year old amber from a valley in Myanmar.

  • The foot was unusual because its third digit was much longer than any of its other toes.

  • And I'm not talking, like, a smidge longer.

  • This toe was about 40% longer than the other ones, and about 1/5 longer than its lower

  • leg bone.

  • When researchers tried to classify this thing, they were a little stumped.

  • Because no other birdliving or extincthad feet like this.

  • So they put this new animal in a group all on its own and called it Elektorornis chenguangi,

  • meaningamber bird.”

  • Names aside, this whole long toe thing was kind of weird, and scientists are still unsure

  • exactly why Elektorornis had it.

  • They suggest in their paper that maybe it was a tree-dwelling bird, so the long toes

  • helped it grip branches, and the two really long toes could help it fish food out of holes

  • in tree trunks.

  • Part of that is inspired by the fact that the modern aye-aye lemur also has a similarly

  • long toe.

  • So this could be a sign of convergent evolution, where similar traits develop because of similar

  • environmental challenges.

  • One way or another, this specimen showed scientists that birds were evolving all sorts of weird

  • solutions as they branched out into different areas of their environment.

  • And, like the other examples on this list, those details might have been lost if it weren't

  • for amber.

  • So, the next time you watch Jurassic Park, go ahead and marvel at the things tree resin

  • can do.

  • It definitely won't be bringing back the dinosaurs any time soonbecause good DNA

  • samples just don't last that long.

  • But it is an excellent time capsule.

  • Thanks for watching this episode of SciShow!

  • If you enjoy the show and want to help us create more free content like this, there

  • are a few ways to support our workincluding becoming a channel member!

  • Channel members help keep SciShow going, and as our way of saying thanks, they also get

  • some perks!

  • Like cool badges and exclusive emojis to use in the chat, and members-only posts in the

  • community tab.

  • If you're already a memberor support SciShow in other waysthank you!

  • We're seriously so glad to have you.

  • And if you want to learn more about channel memberships, you can click thejoin

  • button below this video.

  • {♫Outro♫}

{♫Intro♫}

字幕與單字

影片操作 你可以在這邊進行「影片」的調整,以及「字幕」的顯示

B2 中高級

我們在琥珀發現的6個最酷的東西 (6 of the Coolest Things We've Found in Amber)

  • 1 0
    林宜悉 發佈於 2021 年 01 月 14 日
影片單字