1. The Importance of Rainforests
Rainforests have been called the womb of life because they are home to 50-90% of the
species on Earth. Worldwide, several hundred million forest-dwelling people live in or
depend on rainforests. Many of the world’s important food crops and domestic animals
have been developed from rainforest species. Human beings depend on rainforests in
numerous ways, but it would be wrong to suggest that they should be preserved purely
so that they can be exploited by humans.
Because of tropical deforestation, it has been estimated that at least 40 species are
perishing every day. This is a rate hundreds of times faster than at any period in
recent geological time.
Tropical forests cover only 12 per cent of the land area of the Earth, yet they are
home to between 50 and 90 per cent of the world's species. They contain 90% of
non-human primates, 40% of all birds of prey and 80% of the world's insects and
over 60% of all known plants. Because one species in a tropical forest may be
found in a small area and nowhere else, the destruction of relatively small areas of
forest can cause extinctions.
No one knows just how the rest of the global ecosystem depends on rainforests, but
we may find out in the next 30 to 50 years. That is how long it is estimated that it
will take for tropical forests to disappear altogether if current trends continue.
This situation has been likened by biologists Anne and Paul Ehrlich to an aeroplane
losing the rivets which keep it together. No one knows how many rivets the plane
can lose before it falls apart.
Rainforests are a vital source of medicines. Today, less than 1% of the world's
tropical forest plants have been tested for pharmaceutical properties, yet at least
25% of all modern drugs came originally from rainforests. Most were first discovered
and used by indigenous peoples.
Annual worldwide sales of plant-derived pharmaceuticals currently total $20 billion.
These include such drugs as Digitoxin, Vincristine, Emetine, Physostigmine, Atropine,
Morphine, Reserpine, D-Tubocurarine, and Quinine. All were first used by rainforest
shamans and healers.
An impressive 70% of all plants known to have anti-tumour properties come from
tropical rainforests. Any one of these could lead to breakthroughs in the treatment of
cancer. The potential of this living pharmaceutical factory remains almost completely
The potential and fragility of the rainforests as an invaluable source of medicine is
clearly illustrated in the following account from the World Rainforest Report no.26:
"Starting with twigs from a Malaysian gum tree, researchers in 1991 isolated a
compound that blocked the spread of the AIDS virus in human cells. The team sent
biologists racing back to Malaysia for more samples from the tree. But when they got
to the swamp, the tree was gone, it had been cut down. And no tree found since has
produced the same compound. " No identical trees have been found in the
immediate area and samples from the same species found elsewhere did not yield
the same compound.
In Sarawak, the Penan people use over 50 medicinal plants which they harvest from the
primary forest - plants that are used as poison antidotes, contraceptives, clot ting
agents, general tonics, stimulants, disinfectants, remedies for headaches, fever, cuts
and bruises, boils, snake bite, toothache, diarrhea, skin infections and rashes,. No
other form of agriculture has proved to be sustainable in tropical forest areas.
damaged. In Britain, the figure is 64% and in Czechoslovakia, 70%.
Strata of the Rainforest
Different animals and plants live in different parts of the rainforest. Scientists divide the
rainforest into strata (zones) based on the living environment. Starting at the top, the strata
EMERGENTS: Giant trees that are much higher than the average canopy height. It
houses many birds and insects.
CANOPY: The upper parts of the trees. This leafy environment is full of life in a
tropical rainforest and includes: insects, birds, reptiles, mammals, and more.
UNDERSTORY: A dark, cool environment under the leaves but over the ground.
FOREST FLOOR: Teeming with animal life, especially insects. The largest animals
in the rainforest generally live here.
Animals of the Rainforests
An incredible number of animals live in rainforests. Millions of insects, reptiles,
amphibians, birds, and mammals call them home. Insects are the most numerous
animals in rainforests. Tropical rainforests have a greater diversity of plants and
animals than temperate rainforests or any other biome.
In temperate rainforests, most of the animals are ground dwellers and there are
fewer animals living in the forest canopy.
Where are Rainforests?
Tropical rainforests are found in a belt around the equator of the Earth. There are
tropical rainforests across South America, Central America, Africa, Southeast Asia
and Australia (and nearby islands). Click here for more information.
Temperate rainforests are found along the Pacific coast of the USA and Canada
(from northern California to Alaska), in New Zealand, Tasmania, Chile, Ireland,
Scotland and Norway. They are less abundant than tropical rainforests.
Rainforests are tremendously rich in animal life. Rainforests are populated with insects (like
butterflies and beetles), arachnids (like spiders and ticks), worms, reptiles (like snakes and
lizards), amphibians (like frogs and toads), birds (like parrots and toucans) and mammals
(like sloths and jaguars).
Different animals live in different strata of the rainforest. For example, birds live in the
canopy (upper leaves of the trees) and in the emergents (the tops of the tallest trees). Large
animals (like jaguars) generally live on the forest floor, but others (like howler monkeys and
sloths) are arboreal (living in trees). Insects are found almost everywhere.
Many species of rainforest animals are endangered and many other have gone extinct as the
number of acres of rainforests on Earth decreases.
As in any food web, there are more plant-eaters than meat-
eaters (and many more plants than plant-eaters). There are
also more small animals than large animals. Insects are the
most numerous animals in rainforests.
Although there is intense competition between animals, there
is also an interdependence. When one species goes extinct, it
can affect an entire chain of other species and have
Protection from Predators
Animals are always in danger of being eaten and have developed many methods of
protecting themselves from hungry animals.
Hiding: Some animals simply hide from predators, concealing themselves in burrows,
under rocks or leaves, in tree hollows, or in other niches where they are hard to find.
Camouflage: Camouflage is another way of hiding in which the animal blends into its
environment. Many animals, like the "walking stick" insect and the Indian Leaf
Butterfly (Kallima inachus) are camouflaged so well that they are virtually invisible
when they are standing still. Sloths are covered with a greenish layer of algae which
camouflages their fur in their arboreal environment. Sloths also move very slowly,
making them ever harder to spot.
Scaring predators: Some animals try to convince predators that they are bigger and
more fierce than they really are. For example, the larva of the lobster moth (Stauropus
fagi), whose larva looks like a scorpion, but is in fact completely defenseless. Many
butterflies have large "eye" designs on their wings. This makes them look like the
head of a very large animal instead of a harmless butterfly, and scares many predators
Warning colors: Poisonous animals openly advertise their defense methods, usually
with bright colors and flashy patterns. When a predator eats one member of the group,
it will get sick. This memory will stay with the predator, who will avoid that type of
animal in the future. This method sacrifices a few individuals in order to protect the
entire group. Examples of poisonous animals include the Monarch butterfly. Other
animals (poisonous or not) have come to mimic poisonous butterflies, obtaining the
benefits of their poisonous "twins." This is called mimicry.
What makes Tropical Rain Forests
The rain forests are home to half of the Earth's plant and
They are winter homes to many birds that breed in temperate
Tropical rain forests are some of
the most beautiful wildernesses on our
They are home to tribal cultures
that have survived successfully in the forests for many thousands of
The forests are a potential source of medicinal plants that may
benefit everyone on Earth.
The ecosystem of the rain forest is based on the most complex
interdependence of plants and animals. This is both the forest's
strength and its weakness: highly specialized organisms are
particularly vulnerable to disturbance, because they cannot adapt fast
enough to survive the change.
Tropical rain forests help maintain global rain and weather
patterns. Much of the water that evaporates from the trees returns in
the form of rainfall. Removal of the forest can change the natural
Comparison of Where
Nutrients are Found in an
Comparison of Where Nutrients are Found in an
Ecosystem Based on the averaging of major nutrients.
Tropical Rain Forest Oak Woodland
52% in Vegetation 31% in Vegetation
48% in Soil 69% in Soil
Rainforests are very dense, warm, wet forests. They are
havens for millions of plants and animals. Rainforests are
extremely important in the ecology of the Earth. The plants of
the rainforest generate much of the Earth's oxygen. These
plants are also very important to people in other ways; many
are used in new drugs that fight disease and illness.
Animals that Live in Rainforests: Ridiculously huge numbers of
animals live in rainforests, including microscopic animals,
invertebrates (like insects and worms), fish, reptiles,
amphibians, birds, and mammals. The different rainforests of
the world support different populations of animals.
Bandicoot Echidna Platypus Guinea Pig
Green Tree Ulysses
Cassowary Rock Rabbit Snake butterfly