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          ARRoGANT                CoURiERS      WiTH     ESSaYS

Grade Level:       Type of Work           Subject/Topic is on:
 [ ]6-8                 [ ]Class Notes    [Essay on the Ecology    ]
 [x]9-10                [ ]Cliff Notes    [of Rainforests          ]
 [ ]11-12               [x]Essay/Report   [                        ]
 [ ]College             [ ]Misc           [                        ]

 Dizzed: 07/94  # of Words:1266  School: ?              State: ?
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                        The Ecology of a Rain Forest

     In 1980, the estimated amount of rain forests in the world was 40,000
square miles.  This number decreases each year by roughly 1,000 square
miles due to construction and the resources being used for profit.  It is
too bad, because the rain forest is one of the most beautiful places on
earth.  It is the most diverse, containing the most species of living
things, much more than anywhere else, and most have yet to be identified.
All rain forests are located on earth's "green belt", that is, the area
roughly around the equator that covers all the area from Mexico and the
northern area of South America, to Africa, to India, streching out to
Indonesia, the northern tip of Australia and all the way to New Guinea.
This area is heavily covered with flora and fauna, and it abounds with
life.  In a rain forest, it is very wet and it rains every day or every
other day very heavily.  There is a high and steady level of heat and
moisture.  There are some general layers to the rain forest.  It starts 135
feet up in the air, with the lofty crowns of the tallest trees in the
jungle.  They take the most light, heat, rain and the most punishment from
the winds.  Woodpeckers hunt insects in this layer, and also the black and
white Colobus monkey can be found here, ready to lauch into the air, using
his specially developed tail as a rudder to guide his flight.  Beneath this
is the second layer of trees, whose crowns form a forest canopy.  Rain
filters through this canopy, and the top sides of the crowns hold a large
amount of ferns and other small plants whose roots never touch soil.  They
live off the water and nutrients held in the small pockets of the leaves
and branches.  Tree frogs and chimpanzees live here, burrowing holes to
live in the vast vegetation.  The third layer is called the "understory".
This grows beneath the canopy.  The gorilla makes this his regular hangout,
also pythons lie here waiting for prey.  The dim forest floor teems with
life.  Termites and ants feed on all the decomposing matter on the ground,
and elephants make their way down a path of moss.  Butterflies move
silently by, and the air is still and very humid.  These are the layers
that make up the rain forest's complex ecology.  In the rest of the essay I
will describe some of the life forms found in the rain forest, and ways
they affect the environment.  In the rain forest, plants develop poisonous
alkaloids to protect against insects, and insects develop complex digestive
chemistry to overcome these poisons.  Some of these plant alkaloids give
native indians great poisons for darts, and to cancer researchers hope for
a new medicine.  The rain forest root systems are so efficient that almost
all of the nutrients in decaying plants are recycled into new ones.  Most
roots are found within three inches of the surface in heavy clay or at the
surface in sandy soils.  Tiny rootlets grow up and attach themsleves to
leaves.  When the leaf decays, miniscule fungi on the rootlets take over
and send threadlike projections into the leaf which absorbs all of the
leaf's nutrient material.  The phosphorous that the fungi produces is taken
by the root, and in turn gives the fungus sugars from the tree.  Also,
termites and ants break down the forest litter.  In a small lake in the
middle of the rain forest, a small lizard skims across the water away from
danagerous prey and attacks its own victim by suprise, yet another marvel
of the tropical rain forest.  Mutualism occurs in the jungle with a
specialized ant and a swollen-thorn acacia.  The acacia provides budlike
leaflet tips which are called Beltian bodies, which the ants give to their
young for food.  The insects hollow out the tree's thorns when soft and
green and raise their young inside.  The acacia doesn't have chemical
defenses to repel dangerous and damaging insects and demands pure sunlight
for proper growth.  The ants patrol the tree day and night.  If any insect
lands on the tree, they bite it with a poisonous sting.  They also attack
plants that grow onto the tree, such as a vine.  In this case, they would
attack the vine at it's base and pull it off the tree.  There are also
small leaf-cutting ants in the jungle that cut a portion of a leaf, bring
it to their home, and chew it to a pulp and inject a body fluid to create a
wet mulch.  On this mulch grows the only food of this particular ant -- a
fungus that has only one species.  The mysterious part about this is that
any spores that could develop on the mulch and contaminate it don't
develop.  Paper wasps in the rain forest have to bail out their home after
a heavy shower.  They lap up a mouthful of water from the colony, and then
spit it out onto the forest floor.  They also coat the small stalk that
attaches the nest to the branch of a tree with a sticky black sectretion
that repels some ants.  But there are still some predators, such as jungle
katydids which eat the leaves, and some species of ants that are not
repelled by the black secretion.  In one rain forest, there is a kind of
toad that is voiceless.  So for the male to attract a mate, nature gave it
a very noticeable characteristic -- a flourescent orange color, which is
unmistakable.  The females are blackish green with scarlet spots on them.
In April and May, mating takes place.  Where pools are formed on the forest
floor by water trickling down trees, females lay around 200 eggs.  After
the males fertilize them, the embryos live in their aquatic world for about
two weeks, then after that they hatch and mature.  This species was
discovered in 1964 and it helped win government protection for Monteverde,
which is the place where these frogs can be found.  Biologist Jay M.
Savage, amazed by the frogs, once wrote "I must confess. . .my. .
.disbelief and suspicion that someone had dipped the examples in enamel
paint."  There are other species of frogs, such as the green leaf frog,
whose green body and glowing red eyes is an incredible sight.  They extrude
and fertilize their eggs on a leaf over water.  Young that are ready to
leave their embryo drop into the water below.  Also the poison-arrow frog
is an interesting variety.  The males battle for dominance and mates.  Two
can struggle for hours until one give up and croaks "uncle".  Their color
warns predators of their composition which could prove toxic for snakes and
other such beasties.  The Dendrobates Granuliferus frog doesn't have young
that develop in water.  Instead, the tadpoles cling to the mother's wet
back.  She transports them this way from place to place, usually depositing
them in a cup of rainwater in a high branch safe from predators.  She
immerses herself in the water at first until the young let go of her body
and swim into the water.  A rare bird found only in rain forests, the
quetzal, is a beautiful sight.  They have long colorful tails which have
long been worn by royalty of the Colombian Indians, who called the birds
sacred.  It is beautiful animals like these that might start spur nations
into preserving more of their rain forests, in hopes of keeping one of the
most complex and interesting ecologies on earth.
