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ropical Rainforest: Animals
Tropical rainforests support a greater number and variety of animals than any other
biome. One of the reasons for this great variety of animals is the constant warmth.
Tropical rainforests also provide a nearly constant supply of water and a wide variety of
food for the animals. Small animals, including monkeys, birds, snakes, rodents, frogs,
and lizards are common in the tropical rainforest. Many of these animals and a
multitude of insects never set foot on the ground. The animals use the tall trees and
understory for shelter, hiding places from their predators, and a
source of food.
Animal adaptation
Because there are so many animals competing for food, many
animals have adapted by learning to eat a particular food eaten by
no other animal. Toucans have adapted by developing long, large
bill. This adaptation allows this bird to reach fruit on branches that
are too small to support the bird's weight. The bill also is used to
cut the fruit from the tree.
The sloth uses a behavioral adaptation and camouflage to survive
in the rainforest. It moves very, very slowly and spends most of its
time hanging upside down from trees. Blue-green algae grows on
its fur giving the sloth a greenish color and making it more difficult
for predators to spot.
Plant Adaptations
1. Bark
In drier, temperate deciduous forests a thick bark helps to limit moisture evaporation
from the tree's trunk. Since this is not a concern in the high humidity of tropical
rainforests, most trees have a thin, smooth bark. The smoothness of the bark may also
make it difficult for other plants to grow on their surface.
2. Lianas
Lianas are climbing woody vines that drape rainforest trees. They have adapted to life
in the rainforest by having their roots in the ground and climbing high into the tree
canopy to reach available sunlight. Many lianas start life in the rainforest canopy and
send roots down to the ground.
3. Drip Tips
The leaves of forest trees have adapted to cope with
exceptionally high rainfall. Many tropical rainforest leaves
have a drip tip. It is thought that these drip tips enable rain
drops to run off quickly. Plants need to shed water to avoid
growth of fungus and bacteria in the warm, wet tropical
rainforest.
4. Buttresses
Many large trees have massive ridges near the base that can
rise 30 feet high before blending into the trunk. Why do they
form? Buttress roots provide extra stability, especially since
roots of tropical rainforest trees are not typically as deep as those of trees in temperate
zones.
5. Prop and Stilt Roots
Prop and stilt roots help give support and are characteristic of tropical palms growing
in shallow, wet soils. Although the tree grows fairly slowly, these above-ground roots
can grow 28 inches a month.
6. Epiphytes
Epiphytes are plants that live on the surface of other plants,
especially the trunk and branches. They grow on trees to take
advantage of the sunlight in the canopy. Most are orchids,
bromeliads, ferns, and Philodendron relatives. Tiny plants
called epiphylls, mostly mosses, liverworts and lichens, live
on the surface of leaves.
7. Bromeliads
Bromeliads are found almost exclusively in the Americas.
Some grow in the ground, like pineapple, but most species
grow on the branches of trees. Their leaves form a vase or
tank that holds water. Small roots anchor plants to
supporting branches, and their broad leaf bases form a waterholding tank or cup. The tank's capacity ranges from half a
pint to 12 gallons or more. The tanks support a thriving ecosystem of bacteria, protozoa, tiny crustaceans, mosquito and
dragonfly larvae, tadpoles, birds, salamanders and frogs.
Mangroves
On tropical deltas and along ocean edges and river estuaries,
trees have adapted to living in wet, marshy conditions. These
trees, called mangroves, have wide-spreading stilt roots that
support the trees in the tidal mud and trap nutritious organic
matter.
Nepenthes
Pitcher plant vines in the family Nepenthaceae have leaves
that form a pitcher, complete with a lid. Sweet or foulsmelling nectar in the pitcher attracts insects, especially ants
and flies, that lose their grip on the slick sides and fall into
the liquid. Downward-pointing hairs inside the pitcher
prevent the insects' escape. The insects are digested by the
plants and provide nutrients. Pitcher plants are not epiphytes
but climbers rooted in the soil.
Economic Plants
Our daily dependence on plant products of tropical origin is astounding. For
instance, Latin America and Africa are major suppliers of coffee and cacao (from
which we derive chocolate), while Asia produces most of our rice and natural rubber.
Our lives are enriched by beautiful hardwoods, spices, essential oils and fruits. In
addition, tropical countries export many fibers, gums, resins, dyes, and plant essences
that we may never see directly, but which are widely used in medicine and industry.
This section highlights some of these important plants.
The Tropics in World Trade
Plant products like those just mentioned are often referred to as "commodities" or
"cash crops." Unlike many exports from the industrialized economies, commodities
are usually exported in minimally processed states as raw materials. Whether tropical
nations should continue to rely extensively on these exports to fuel their emerging
economies is a hotly debated subject, with critics maintaining that overproduction
depresses world prices of these materials and diverts arable land from food production
for local markets. Regardless, patterns of trade in commodities are not likely to
change significantly in the near future.
Trade vs. Environmental Concerns
As tropical nations seek to increase their share in the world marketplace, a key
question is the best way to balance these strategies with the needs to conserve and
manage remaining forested areas. Indiscriminate harvesting techniques and clearing
large tracts for cultivation or ranching have been all too characteristic of the past. The
future will require more appropriate means of extracting plants or their products if we
are not to lose the many thousands of other tropical species holding genetic
"blueprints" important to our future. This will require strong international leadership
on economic and environmental fronts and, for all citizens of the world, a willingness
to rethink our use of the Earth's resources.
Native Origins of Economic Plants
Plants listed below are native to these regions. Many are now grown in other areas of
the tropics also.
World-Wide
Bamboo
Bambusa spp.
Phyllostachys spp.
Grass Family
Bamboo is the world's largest grass and is native to many
parts of the world. It is grown throughout the tropics and is
used as a source of food as well as for construction and
weaving. It has great strength and is used in Japan as
scaffolding for building skyscrapers.
Australasia
Banana and Plantain
Banana family
are very closely related. Plantains,
like a starch than a fruit. Both are
Australia but are now grown
Though commonly called "trees",
world's largest herbaceous plants,
woody stems like trees.
Musa x paradisiaca
Bananas and plantains
however, are used more
native to East Asia and
throughout the tropics.
they are actually the
as they do not develop
Sugar Cane
Saccharum officinarum
Grass family
The stems of this grass plant can reach 10 feet tall and are
rich in sugar. The stems are crushed to extract the sweet
juice, which is then processed to obtain sugar. Sugar cane is
native to New Guinea. It was introduced into the New World
by Columbus on his second voyage in 1493.
Nutmeg and Mace
Myristica fragrans
Nutmeg family
from different parts of the same
and mace is the red net-like fiber
seed. Nutmeg is native to the
Islands).
Nutmeg and mace come
fruit. Nutmeg is the seed
(aril) that surrounds the
Moluccas (Spice
The Americas
Cassava
Manihot esculenta
Spurge family
Native to Mexico, Guatemala, and northern
Brazil, cassava is now grown throughout the
tropics. It is the starch staple of over 500
million people. The roots are peeled and boiled
(like potatoes) or made into a flatbread. It is in
the same family as poinsettia and wild varieties
can be toxic if not prepared correctly. Tapioca is
made from heated, purified cassava starch and
is a common thickening
agent.
Chicle or Sapodilla
Sapodilla family
base for chewing gum,
latex (sap) of a tree native
Mexico to northern Brazil.
are scored with diagonal
Manikara zopota
Chicle, the original
comes from the
from southern
When the trunks
down-sloping cuts,
the latex flows from the bark. It is collected, molded into blocks,
and shipped for processing, where sugar and flavoring are added.
Today chicle has been largely replaced with the latex from other
trees and by synthetic gums. The fruit of the chicle tree, sapodilla,
is delicious.
Allspice
Pimenta dioica
Myrtle family
Allspice is not a mixture of spices but rather a
single fruit that contains the flavors of nutmeg,
cinnamon and cloves. The Maya used allspice to
embalm the bodies of their leaders.
Rubber
Hevea brasiliensis
Spurge family
Rubber trees are native to
the Brazilian
Amazon but now are also
grown in
plantations in Southeast
Asia. Diagonal
slashes are made in the
bark of the tree and
the latex sap that exudes is
collected. The latex
is mixed with water and
heated over a
smoky fire to produce a ball of rubber ready for processing. Today
most rubber is synthetic; natural rubber is restricted to specialized
uses.
Cacao
Theobroma cacao
Sterculia family
Cacao is native to the eastern Andes. The Maya
and Aztecs made a beverage from the seeds of
this plant calling it the "food of the gods." The
seeds, after being fermented and pulverized,
were mixed with water to produce a beverage.
It was not until Europeans added sugar and milk
that the world came to know chocolate as we do
today. Today, major production areas are in West Africa, Brazil, and
Mexico.
Vanilla
Vanilla planifolia
Orchid family
Vanilla is the only orchid that is grown for
purposes other than its flowers. It is native to
Mexico, and was introduced into Europe in the
mid-16th century by the Spanish. The flowers
are pollinated by hand or by a small bee and
produce an elongated fruit, or "bean", which is
fermented to produce vanilla beans. True vanilla flavoring is
extracted from the fermented seed pods with alcohol. Today most of
the world's supply is grown in the Seychelles, Central America, and
Madagascar.
Indo-Malasia
Ginger
Zingiber officinale
Ginger family
Native to southern Asia, ginger is now grown
throughout the tropics with major production in
Nigeria, Sierra Leone, Jamaica, and India. The
plant's rhizome (stem that grows at ground
level like iris) is used fresh as well as dried and
ground. It is a common ingredient in Asian
cooking and flavors ginger snaps, ginger ale,
ginger beer, ginger cake, and pumpkin pie.
Black Pepper
Piper nigrum
Pepper family
Black pepper and hot pepper (Capsicum) are
not closely related. Black pepper originated in
India and Cambodia and was the spice that,
above all, drove the spice trade. The green,
immature fruits of the pepper vine are
harvested and dried, turning black upon drying. White pepper is
obtained by letting the "berries" turn red (ripen) and then removing
the outer husk, leaving the straw-colored "kernel". It is milder than
black pepper.
Jackfruit
Artocarpus heterophyllus
Mulberry family
Native to Southeast Asia, jackfruit is now grown
throughout the tropics. The fruits can weigh up
to 100 pounds and are produced directly on the
trunks and branches. Fruits are green or yellow
and "warty" on the surface. Inside, the seeds
are surrounded with a fragrant yellow flesh
tasting like pineapple and bananas. The seeds
are also eaten boiled or roasted.
Rattan
Calamus spp.,
Daemonorops spp.
Palm family
Native to Asia, rattan is the
collective name for
the climbing palms. They
are rope-like,
woody climbing plants that
can grow to 600
feet long. After being
collected from the
forest the stems are boiled in oil and scoured in sand or sawdust to
remove their natural gums and resins. The outer skins are removed
and used to weave furniture, baskets, screens, and chair seats. The
inner core is used for making baskets.
Africa
Cola or Kola
Cola acuminata, C. nitida
Sterculia family
Cola is related to cacao, the plant from which chocolate is
made, and is best known as a flavoring in cola soda pops.
Cola seeds, called "nuts", are rich in caffeine. It is native to
West Africa but now is also grown commercially in Jamaica
and Brazil. In West Africa a cola drink is made by mixing
the pulverized, fermented and dried beans with water.
Ebony
Diospyros spp.
Ebony family
Ebony is in the same genus as the
North American persimmon, D.
similar fruit. Its heartwood gives it
wood is extremely hard and will
for piano keys, cutlery handles,
carvings. It is native to West
logs are rare due to over harvesting.
virginiana, and has a
commercial value. The
sink in water. It is used
musical instruments and
Africa. Good quality
Interesting Plants 1
Tropical plants comprise about 160,000 of the estimated 250,000 species of plants
on Earth. Following is a sample of the many interesting plants that grow in the tropics.
Double Coconut
Lodoicea maldivica
Palm family
The largest seed in the plant kingdom looks like two coconuts fused together, giving
rise to this fan palm's common name. The plant is tender and very slow-growing,
especially when young (for instance, the nut takes a year to germinate and another
year to form its first leaf); hence, it is rarely cultivated. Eventually, it can attain
heights of 100 feet and leaf blades to 20 feet in length and 12 feet in diameter. The fan
palm is native to only a few islands in the Seychelles, located off the east coast of
Africa in the Indian Ocean. For centuries its nuts were mistakenly thought to come
from the Maldive Islands, an error preserved in its Latin name.
Banyan Tree
Ficus benghalensis
Mulberry family
One of the wonders of the plant kingdom, the banyan, begins
life as an epiphyte, growing on another plant and taking its
moisture and nutrients from the air and rain. The banyan
sends down aerial roots which become accessory "trunks,"
supporting the tree's immense crown and allowing it to
extend over several acres. Widely cultivated in the tropics,
the banyan is native to India and Pakistan, where it is
considered sacred.
Coccoloba
Coccoloba pubescens
Buckwheat family
Sometimes referred to as "Eve's umbrella," coccoloba can
grow to 80 feet but in its juvenile stage is grown as a pot
plant for its large, veined ornamental leaves. "Pubescens"
refers to the fine hairs, in this case rusty-colored, that cover
the leaves' undersides.
Talipot Palm
Corypha umbraculifera
Palm family
"bears an umbrella," an appropriate
ornamental. The talipot palm's
largest in the plant kingdom.
grow trunks to 80 feet in height and
leaf blades to 16 feet in diameter.
flowering and fruiting.
Freycinetia
Freycinetia multiflora
Pandanus family
The orange growths on this male specimen are actually
leaves which will slowly peel off to expose small green male
flowers.
Interesting Plants 2
"Umbraculifera" means
name for this
flower clusters are the
Specimens can easily
3 feet in diameter and
The plant dies after
Phillipine Fig
Ficus pseudopalma
Mulberry family
This plant's unusual leaf formations, giving the appearance of a
pompon on a pole, could lead you to mistake it for a palm,
hence the name "pseudopalma."
Peacock Plant
Calathea makoyana
Maranta family
The peacock plant is well adapted to the low light of the forest
floor. Its broad leaves help capture the limited light and the redpurple pigment on the underside of the leaves is a special
adaptation which captures the greenish light present at the forest
floor. It has striking markings on the upper surface of the leaf.
These markings occur naturally; it is not a cultivar. Like the
prayer plant (Maranta sp.) the leaves of the peacock plant fold up at night.
Panama-Hat Plant
Carludovica palmata
Cyclanthus family
Often cultivated in tropical gardens as an ornamental or as a
source of fiber, this plant is palm-like but is not a palm. In
Ecuador, the leaves are woven into the famous Panama hats,
a name conferred during the days of the California Gold
Rush, when the hats were shipped to the state from Ecuador
indirectly by way of Panama.
Gnetum
Gnetum leyboldii
Gnetum family
This vine is not a flowering plant
gymnosperms, vascular plants that
("gymnosperm" literally means
kinds of gymnosperms are the
but one of the
bear exposed seeds
"naked seed"). Other
cycads, gingkos, and
conifers. Gnetum is uncharacteristic in that it is a vine and
has large, broad leaves.
Bauhinia
Bauhinia blakeana
Pea family
This evergreen tree, which can grow to 40 feet or more,
bears curious, bi-lobed leaves reminiscent of bull hooves. Its
showy, reddish purple flowers are very orchid-like in
appearance. All plants in cultivation originated from a single
tree discovered in Canton, China.
Fishbone Cactus
Epiphyllum anguliger
Cactus family
Sometimes called the "fishbone cactus,"
tropical rainforests of southern Mexico.
is adapted to the relatively dry
forest canopy. Spineless, its branches
actually modified stems. It flowers for
year, with fragrant pale yellow blooms.
this plant lives in the
It is an epiphyte and so
conditions of life in the
resemble leaves but are
just a few nights each
Interesting Plants 3
Sacred Fig
Ficus religiosa
Mulberry family
This large, fast-growing tree begins life as an epiphyte. Its leaves
are excellent, if exaggerated, examples of drip tips, which allow
rapid shedding of water. Widely planted in the tropics, in India
the tree is sacred to Hindus and Buddhists.
American Mangrove
Rhizophora mangle
Mangrove family
The mangroves are widely distributed
throughout the
tropics and in southern Florida, growing in
areas of salt water,
such as tidal shores and marshes. The many
arching aerial roots
make dense tangles that stabilize the
surrounding soil,
prop the tree, and assist in absorbing water
and minerals. Seeds
germinate while still attached to the parent
plant, giving them a
head start on growth when they fall and lodge in the mud. Mangrove bark is an
important source of tannin, used in tanning, dyeing, making ink, and medicine.
American mangrove is also referred to as red mangrove.
Ilang-Ilang
Cananga odorata
Annona family
This southeast Asian tree, which can grow to 80 feet, is also
sometimes spelled "ylang-ylang." Its greenish yellow,
drooping flowers are exceedingly fragrant, and their oils are
distilled for use in some of the world's most expensive
perfumes.
Screw Pine
Pandanus copelandii
Pandanus family
trees and shrubs in the Pandanus
for their dramatic architecture and
name "screw pine" reflects their
growth. In areas where the plants
are often woven into thatch,
while their flowers are sources for
medicines.
Giant Bamboo
Dendrocalamus giganteus
Grass family
This Southeast Asian bamboo became famous during World
War II for its ability to overgrow jeeps rapidly, reportedly
sometimes overnight. A mature specimen can reach more
than 100 feet in height and 12 inches in diameter.
Not true pines, the many
family are noteworthy
aerial prop roots. The
twisted patterns of
are native, their leaves
baskets, hats, and mats,
perfumes and folk