Home
เข้าสู่ระบบ
สมัครสมาชิก
เนื้อหาการเรียน
Loading...
Could This Thing *Really* Fly? - Video học tiếng Anh
ฝึกฟัง
ฝึกฟัง
/
Video
/
MinuteEarth
/
Could This Thing *Really* Fly?
Could This Thing *Really* Fly?
เลือกโหมดการเรียน:
ดูคำบรรยาย
เลือกคำ
เขียนคำใหม่
Highlight:
3000 Oxford Words
4000 IELTS Words
5000 Oxford Words
3000 Common Words
1000 TOEIC Words
5000 TOEFL Words
คำบรรยาย (56)
0:00
This video is brought to you by FarmKind. More about them at the end of the video.
0:05
The Quetzalcoatlus – one of the largest pterosaurs that ever lived
0:08
– was able to… fly?!
0:11
That doesn’t sound right.
0:13
I mean, look at this thing – it’s the size of a giraffe!
0:17
However, giant pterosaurs’ ability to fly is
0:20
really well-established in the scientific community.
0:23
So how on Earth did this giant manage to fly?
0:28
Hi, I’m Ever and this is MinuteEarth.
0:32
Thanks to the fossil record,
0:33
we know that pterosaurs had wings with elongated hand bones, just like every
0:38
other flying vertebrate. But simply having wings doesn’t mean you can actually fly.
0:43
If you’re too heavy for the size of those wings – or if you can't flap them fast enough – you’ll
0:49
never get anywhere. And compared to the biggest flying creatures alive today – the Kori bustard,
0:55
or the wandering albatross, or even the Andean condor,
0:58
depending on how you measure it – the Quetzalcoatlus was way, WAY bigger.
1:03
But, despite this giant pterosaur’s wingspan,
1:06
scientists estimate that it was only about as heavy as a large pig.
1:11
Now with the wing-to-mass ratio looking more decent,
1:14
giant pterosaurs still needed to be strong enough to flap them.
1:18
And while wing muscles themselves aren’t preserved in the fossil record,
1:22
we know pterosaurs had huge bumps in their forelimb bones and highly modified breastbones,
1:28
with ample attachment space for powerful chest muscles – just like modern flying birds do.
1:34
So it’s reasonable to believe their wing muscles were pretty brawny.
1:38
On top of that, pterosaurs had mostly hollow bones that increased
1:43
the volume of their respiratory system – again, just like modern flying birds –
1:48
which allowed them to deliver tons of oxygen to all those flight muscles!
1:53
All this likely helped a Quetzalcoatlus’s big body stay aloft once it was in the air.
1:59
But getting into the air in the first place is the hardest and most energy-intensive part of flight.
2:05
Flying birds use their strong leg muscles to launch themselves into the air;
2:10
that’s why the bigger a bird is, the larger and more powerful its legs tend to be.
2:16
Giant pterosaurs were so huge that, in order to jump into the air like birds,
2:21
they would have needed truly gigantic legs that would have made them definitely too heavy to fly.
2:27
So they solved the whole launching problem in a different way:
2:31
they used their powerful wings for the dual purpose of taking off and flapping.
2:37
And this strategy is so efficient, that bats independently evolved it as well.
2:43
By the way, I think that this is my favorite fact about giant pterosaurs –and bats, of course.
2:48
Once you look at all the evidence and the facts,
2:50
it makes perfect sense that these giant pterosaurs could truly soar.
2:55
They might look too big and wonky,
2:58
but the Quetzalcoatlus was about as close as we’ve ever come to a flying pig.
3:04
Pigs these days, of course, rarely fly.
3:08
And – sorry to be a downer, especially after that uplifting video - but in a lot of places,
3:13
the conditions they’re kept in are heartbreaking.
3:16
As someone who loves animals, I hate to see any animal suffering so much.
3:20
That’s why we want to help make a genuine positive change with today’s sponsor, FarmKind.
3:27
FarmKind helps improve the lives of animals by recommending expert-reviewed,
3:31
top charities whose work really makes a big difference.
3:34
Like Sinergia Animal, which is helping end the inhumane
3:38
practice of keeping breeding pigs confined in tiny crates.
3:42
FarmKind never takes a cut of your donation; it all goes to the charities helping animals.
3:47
If you sign up for just $15 bucks a month, that’s just 50 cents a day,
3:53
you'll save 350 animals from unnecessary suffering in your
3:57
first year. Use the code MinuteEarth for a 50% boost on monthly donations.
4:04
If even a fraction of this community did that, we'd transform the lives
4:08
of hundreds of thousands of animals. Check out the description for more info. Thanks FarmKind.
