[海洋[DK出版社地球百科丛书]]-Ocean-(DK-Eyewitness-Books)_部分3.pdf

Spines to Grazing away
protect The mon sea urchin
urchin grazes on seaweeds and animals
such as sea mats that grow on
the surface of seaweeds. The
urchin uses the rasping
teeth on the underside
of its shell that are
operated by plex
set of jaws inside, Pelican
known as Aristotle’s diving
lantern. The grazing
activities of urchins
can control how much
seaweed grows in an
area, so if too many Brown
urchins are collected for pelican
food or tourist souvenirs, catches
a rocky reef can e fish in
overgrown by seaweed. beak
Feeding
Sea urchin’s mouth on fishes
Tube-feet used surrounded by five Like all pelicans,
to walk slowly rasping teeth the brown pelican
along the seabed has a big beak with
a large flap of skin
or pouch to capture a
variety of fish. Once they
have spotted their prey, they
Tiny teeth of a dive into the water, but are too
basking shark bulky to dive too far below the
surface. Only brown pelicans dive
for their prey. When the pelican
surfaces, water is drained from the
pouch and the fish swallowed.
To bite or not to bite Tentacle traps
A tiger shark’s tooth is like a multipurpose tool with a The flowerlike Dahlia anemones are deadly traps for
sharp point for piercing prey and a serrated bladelike unwary prawns and small fish that stray too close to
edge for slicing. This shark can eat almost anything from Stinging their stinging tentacles. When the prey brushes past,
hard-shelled turtles to soft-bodied seals and seabirds. tentacle hundreds of nematocysts (stinging cells) are triggered
Tiger The rows of a basking shark’s tiny teeth are and fire their stings. These stings ensnare and
shark’s not used at all, since this shark filters weaken the prey. The tentacles pass
tooth food out of the water with a the stricken prey toward the
sieve of gill rakers. mouth in the anemone’s
centre—the entrance to
the baglike stomach
Any undiges