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The tropical rainforests have
billions of species of plants and animals, more than anywhere
else on earth. Scientists do not yet know all the species
that are to be found in a tropical rainforest.
The reason there
are so many species is because rainforests are very old, some
almost 100 million years old, which means dinosaurs probably lived
in them. About 10,000 years ago the ice caps at the poles spread
out in an Ice Age, but the ice didn't reach the Equator so tropical
rainforests survived and their plant and animal species continued
to evolve.
In the tropics it is always hot and it rains every day. Tropical
rainforests are the wettest places on earth.
Tropical rainforest
plants
Some
canopy trees grow over to over 100 metres high. Many have fruit
that provides food for animals and people. Many rainforest plants
are gathered for food or medicines. This is done without harming
the rainforest.
Many 'every day' foods originated in rainforests, including tomatoes, peppers, corn, rice, coconut, banana, coffee, cocoa, cassava (tapioca), beans and sweet potatoes.
Tropical rainforest:
Plant Adaptations
In order to survive in the hot, wet tropics, plants of the tropical
rainforest have had to develop special features.
Because the weather is hot and wet, trees do not need thick bark to slow down moisture loss and have instead thin, smooth bark.
The layers of rainforest are connected by vines and ferns, and mosses grow on the trees. Liana is a climbing vine that grows on rainforest trees, climbing into the canopy so its leaves get more sunlight.
The leaves of rainforest trees have adapted to cope with the large amount of rain. The leaves are big, thick and waxy, and have 'drip tips' to let the rain drain off quickly.
Many large trees have huge ridges near the base. These buttresses can be 10-12 metres high where they join into the trunk. This may increase the surface area of a tree so that it can 'breathe in' more carbon dioxide and 'breathe out' more oxygen. It may be that they are there to give big trees added support in the wet soil.
Some trees have above- ground roots called
prop and stilt roots. These give extra support to the trees.
These roots can grow about 85 cm in a month.
Some tropical rainforest plants are carnivorous. 
They have a cavity filled with either
sweet or terrible smelling nectar that attracts insects, especially
ants and flies. Inside, the sides are steep and lined with downward
pointing hairs. Insects enter and lose their footing or are prevented
from leaving because of the hair. Rafflesia , in Indonesian rainforests, produces
the biggest flower in the world.
Thousands of flowering
plants grow onto trees so they get sunshine. Their roots are not
in soil, and the plants get their food from air and water. Plants
that do this are called epiphytes (say
epp-ee-fights),
and include orchids, philodendrons, ferns and bromeliads. Bromeliads
are native to the Americas. Bromeliad leaves form a central 'tank'
where water collects. 
Small creatures such as tiny crustaceans,
mosquito and dragonfly larvae, tadpoles, birds, frogs and salamanders
often live there. Some bromeliads grow in soil, but most grow
on tree branches.
A frog in a bromiliad
'tank'
| Find out more about rainforest plants |  |
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If you use any part of this,
acknowledge it in your bibliography like this:
Rainforest Biome
(2002). [Online],
Available: www.kidcyber.com.au
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