Home
Entrar
Registrar
Conteúdo de Aprendizagem
Loading...
Praticar Escuta
Praticar Escuta
/
Video
/
National Geographic
/
The Strange World of Troglobites | 20 Years of Planet Earth | BBC Earth
The Strange World of Troglobites | 20 Years of Planet Earth | BBC Earth
Selecionar modo de aprendizagem:
Ver legendas
Escolher palavra
Reescrever palavra
Highlight:
3000 Oxford Words
4000 IELTS Words
5000 Oxford Words
3000 Common Words
1000 TOEIC Words
5000 TOEFL Words
Legendas (52)
0:00
It takes thousands of generations for
0:02
eyes to be lost. So these species must
0:05
have been isolated for a very long time.
0:09
Many caves are like islands cut off from
0:12
the outside world and from other caves.
0:23
This isolation has resulted in the
0:26
evolution of some very strange
0:29
creatures.
0:32
They are the cave specialists,
0:34
troglobites, animals that never emerge
0:37
from the caves or see daylight.
0:53
These trogloites from Thailand are
0:56
possibly the most specialized creatures
0:58
on Earth, for they live only in cave
1:01
waterfalls.
1:03
The entire population of these cave
1:06
angelf fish seems to be restricted to
1:09
just two small caves.
1:15
It's the same story with other trogler
1:17
bites. There may well be less than 100
1:19
Texas cave salamanders in the wild.
1:39
And the Blelesian white crab is another
1:42
creature that is unique to just one cave
1:45
system.
1:51
Living in perpetual darkness, they have
1:53
all not only lost the pigment in their
1:55
skin, but also their eyes.
2:00
It takes thousands of generations for
2:02
eyes to be lost. So these species must
2:05
have been isolated for a very long time.
2:13
But the blind salamander has other
2:16
highly developed sensory organs.
2:21
Receptors in the skin detect minute
2:24
movements in the water made by its prey.
2:33
External gills help it to breathe in
2:36
water that is particularly low in
2:38
oxygen.
2:50
The cave angelf fish feed on bacteria in
2:54
the fast flowing water, keeping their
2:56
grip with microscopic hooks on their
2:58
fins.
3:10
Food is often in short supply and
3:13
trogabites like the crab have to survive
3:16
on whatever washes into the cave from
3:18
outside.
3:23
A salamander might not encounter food
3:25
for several months, so when something
3:28
does come along, it can't afford to miss
3:30
it.
3:38
It's astonishing that these
3:39
extraordinary cave dwellers managed to
3:42
survive at all.
The Strange World of Troglobites | 20 Years of Planet Earth | BBC Earth - Video học tiếng Anh
