and sea anenomes look
like plants to us, but
they are animals: they
cannot make their own
food. These corals live
in a beautiful reef
where the sea currrents
bring them a constant
stream of food. Corals
are communities of little
animals that live together.
They have moving tentacles
and they catch whatever
floats by in the ocean
currents. They are able
to pull in their tentacles
when something touches
are there corals here, but not plants?
Plants can get more light closer to
the surface. Perhaps the corals, nourished
by organic particles in the water,
can grow fast enough to crowd most
grow in very clear, warm water.
Green algae grow inside the cells
of the coral, and give off oxygen
and some organic material ,which nourish
the corals. The algae are protected
from grazers and strong water currents,
so both parties benefit.
is an example of two different ecological
niches, places in a larger
system where species thrive by specializing
on living on a portion of the resources.
In this way they are not competing
with each other for the same
resources. Everybody gets his own
slice of the pie!
the water is heated by sunlight more
than usual, the corals expel the little
algae in their cells. Then the
corals starve and die. Living
creatures are dependent on the stability
of their environments. They
adapt to the conditions, but are not
adapted to sudden changes.
now many coral reefs are dying.
The scientists believe that this is
partly because global warming is making
the ocean warmer. Coral reefs
are very rich environments, and many
different kinds of fishes and other
animals live in the shelter that they