1.
Fill in the gaps with the correct word from the
box below.
animals attract bioluminescent blue
burglar chemicals cloud
defence empty energetically escape
feet fighting horn
hypnotize impact life
light ocean organs
Prize substrate swimming
tentacles tropical world
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A.
Today we have only explored about 3 percent of
what's out there in the (1)______________. Already we've found the
(2)______________'s highest mountains, the deepest valleys, underwater lakes
and waterfalls. And in a place where we
thought no (3)______________ at all, we find more life and diversity and
density than the (4)______________ rainforest, which tells us that we do not
know much about this planet at all. There is still 97 percent, and either that
97 percent is (5)______________ or just full of surprises. There's fish with
glowing, pulsating eyes. It is just fascinating how cephalopods can, with their
incredible eyes, sense their surroundings, look at light, look at patterns.
When backing into a crevice, they pull their (6)______________ in to make them
look just like algae, and disappears right into the background. Sometimes they
don't want to be seen when they move, because predators can see them. They can
actually slide across the bottom, using the waves and the shadows so as not to
be seen.
B.
Usually if people are familiar with
bioluminescence at all, it is through fireflies. And there are a few other
land-dwellers that can make light -- some insects, earthworms, fungi -- but in
general, on land, it is really rare. In the ocean, it is the rule rather than
the exception. If you go out in the open ocean environment, virtually anywhere
in the world, and you drag a net from 3,000 (7)______________ to the surface,
most of the animals -- in fact, in many places, 80 to 90 percent of the
(8)______________ that you would bring up in that net -- make light. Some of
the colors and patterns are designed to (9)______________.
C.
In the 19th century, the French physiologist
Raphael Dubois ground a clam up and he managed to get out a couple of
chemicals; one, the enzyme, he called luciferase; the (10)______________, he
called luciferin after Lucifer. That terminology has stuck, but it does not
actually refer to specific (11)______________ because these chemicals come in a
lot of different shapes and forms. In fact, most of the people studying
bioluminescence today are focused on the chemistry, because these chemicals
have proved so incredibly valuable for developing antibacterial agents, cancer
(12)______________ drugs, testing for the presence of life on Mars, detecting
pollutants in our waters, etc. In 2008, the Nobel (13)______________ in
Chemistry was awarded for work done on a molecule called green fluorescent
protein that was isolated from the (14)______________ chemistry of a jellyfish,
and it has been equated to the invention of the microscope, in terms of the
(15)______________ that it has had on cell biology and genetic engineering.
Another thing all these molecules are telling us that, apparently,
bioluminescence has evolved at least 40 times, maybe as many as 50 separate
times in evolutionary history, which is a clear indication of how spectacularly
important this trait is for survival.
D.
For animals that are trying to avoid predators
by staying in the darkness, light can still be very useful for the three basic
things that animals have to do to survive: and that is find food, (16)______________
a mate and avoid being eaten. Some fish have three headlights on each side of
their heads. (17)______________ is the color of most bioluminescence in the
ocean because evolution has selected for the color that travels farthest
through seawater in order to optimize communication. So, most animals make blue
light, and most animals can only see blue (18)______________. Blue luminescence
can also be used to attract prey from a long way off. Some fish have two red
light organs. So they use the red bioluminescence like a sniper's scope to be
able to sneak up on animals that are blind to red light and be able to see them
without being seen. A lot of them can release their luciferin or luferase in
the water just the way a squid or an octopus will release an ink (19)______________.
There are a lot of different animals that can do this: jellyfish, squid, and
different crustaceans. Another form of (20)______________ is something called a
burglar alarm -- same reason you have a burglar alarm on your car: the honking
(21)______________ and flashing lights are meant to attract the attention of,
hopefully, the police that will come and take the (22)______________ away. When
an animal is caught in the clutches of a predator, its only hope for escape may
be to attract the attention of something bigger and nastier that will attack
their attacker, thereby affording them a chance for (23)______________.
E.
The viperfish is an extraordinary specimen. It
has got a lure on the end of a long fishing rod that it arches in front of the
toothy jaw that gives the viperfish its name. The teeth on this fish are so
long that if they closed inside the mouth of the fish, it would actually impale
its own brain. So instead, it slides in grooves on the outside of the head. It
has got a built-in flashlight, jewel-like light (24)______________ on its belly
that it uses for a type of camouflage that obliterates its shadow, so when it
is (25)______________ around and there is a predator looking up from below, it
makes itself disappear. It has got light organs in the mouth, it has got light
organs in every single scale, in the fins, in a mucus layer on the back and the
belly, all used for different things -- some of which we know about, some of
which are still a mystery. Another example is the shining tubeshoulder because
it actually has a tube on its shoulder that can squirt out light. What is
shocking is not just the amount of light that it can produce, but the fact that
it is not just luciferin and luciferase. It is actually whole cells with nuclei
and membranes. It is (26)______________ very costly for this fish to do this,
and we have no idea why it does it -- another one of these great mysteries that
needs to be solved.
2.
Match each heading with the correct paragraph
I.
Astonishing examples of underwater creatures
II.
How a living creature makes light
III.
Bioluminescence is essential to many animals
IV.
More common that you would expect
V.
An unexplored part of the world
3.
Answer the following questions using no more
than 3 words from the text.
a)
What do cephalopods use to evade being seen by
predators on the bottom of the sea?
b)
Where is bioluminescence not rare?
c)
What does most modern research of
bioluminescence concentrate on?
d)
What other underwater creatures use luciferin in
the same way that bioluminescent fish do?
