Transcript Tropical Rainforests

Tropical
Rainforests
Tropical Rainforests of the world
A
B
C
Rainforests are found 5° north and south of the Equator
Amazon
Zaire basin
Indonesia
3 main areas of Rainforest
 Amazon Basin – A on the map.
It is South America covering
most of Brazil, the 5th largest
country in the world. It gets its
name from the river Amazon
which flows through it.
 Zaire – B on the map. It is in
central Africa getting its name
from the river running the
through it.
 Indonesian – C on the map. It
gets its name from a group of
islands called Indonesia which
lie between Asia and Australia.
Climate
 Main features
 Reasons Why
Very hot – 27°C daily average
Sun directly overhead at noon
giving intense light and heat
Very wet – over 2000mm rain
annually
Moist air rises quickly in noon
heat. Rising air cools, water
vapour condenses each
afternoon into heavy
convectional rain.
No seasons – same weather
conditions all year
At the Equator every day has
equal hours of daylight and
darkness. No ‘summers’ or
‘winters’.
Layers of the Tropical Rainforest
Epiphytes
Lianas
Shrub layer
Life in each layer
 Emergent Layer: This is
the top layer of the rain
forest. The tall trees
break out above the
canopy layer to the
sunlight. Many of the
birds live in this
area. The birds eat fruit
and fly in the open areas
of the emergent layer.
They look for nesting
places and are away from
predators.
Canopy: The canopy is full of life. It
receives more sunlight than the layers
below. There are plants that grow in this
area. Their roots don't reach the ground.
These are called air plants. The roots get
their moisture from the humid
conditions. The canopy is home to may
birds and monkeys.
Understory and Forest floor
 Understory: This layer
get little light. Many
animals like frogs, bats,
apes, owls, and more live
in this area. Some are
nocturnal. There are
anteaters and leafcutter
ants. Many animals go
from the understory to the
canopy and back. These
two layers are brimming
with life.
Forest floor: This is where many insects
live. Many seeds fall to the forest floor.
Here you will then also find the animals
that eat seeds and bugs. It is very dark
here due to the dense canopy.
Adapting to rainforest life
 Vegetation in the rainforest has evolved characteristics which help
it survive in this unique environment. The illustration shows four
rainforest plants: a fan palm, a strangler fig, a liana and a tree with
buttress roots.
 Each of these plants is adapted to rainforest conditions in a
different way.
 Fan palms have large, fan-shaped leaves that are good for catching
sunshine and water. The leaves are segmented, which allows excess
water to drain away.
 Rainforests have a shallow layer of fertile soil, so trees only need
shallow roots to reach the nutrients. However shallow roots aren't
great for supporting huge rainforest trees, so many tropical trees
have developed huge buttress roots. These stretch from the
ground to two meters or more up the trunk, which help anchor the
tree to the ground.
 Lianas are woody vines that start at ground level, and use
trees to climb up the canopy where they will spread from
tree to tree to get as much light as possible.
 Strangler figs start at the top and work down. The seed
is dropped in a nook at the top of a tree where it starts to
grow, using the debris collected there. Gradually the fig
sends aerial roots down the trunk of the host, until they
reach the ground and take root. As it matures, the fig will
gradually surround the host, the aerial roots will criss-cross
the trunk and start to strangle. Meanwhile the figs branches
will grow taller, dominating the sunlight, while invasive
roots rob the host of nutrients. Eventually the host will die
and decompose leaving the hollow, but sturdy trunk of the
strangler fig.
Animal Life in the
Rainforest
Write a letter
Write an account of a recent visit to the
Rainforest. Send this letter to your friend
or family.
Say what you saw, what you did.
Mention the sights, sounds, animals and
the weather.
Rainforest under threat
An area the size of a football pitch is
removed from the Rainforests every
second
At this rate there will soon be no
Rainforest left
Cattle
ranching
Mining
Farming
Logging
Causes of
Deforestation
Growing towns
Firewood
Forest fires
Roads
Consequences of deforestation
Plants and animals – habitats, food, no
where to live
Soil – washed away by lots of rain. No
good for crops
World climate – no oxygen for people, less
water in the atmosphere so more deserts
Slash and Burn Farming
Native American tribes cut down small areas
of Rainforest to farm. The trees they cut down
are burnt and the ash is spread over the
fields. They do this to add nutrients to the soil
and make it fertile (able to grow more crops).
They farm for only 2/3 years as the rain
washes the nutrients out of the soil. The
farmers then move to another area and
repeat this process.
The original cleared area is then able to
regrow its trees as the surrounding trees are
able to retake it and make new forest.
Soil Conservation
This is working to preserve the
environment so soil is not lost due to the
actions of man.
Problems of human intervention
 Roads divide up parts of the rainforest and can
cut off connections between different biotic and
abiotic systems. For example, a road can stop
monkeys such as the Golden Lion Tamarin from
travelling to gather food and, in turn, distribute
seeds to re-sow plants in the forest.
 Land clearance for farming, transportation and
mining can lead to deforestation. Hardwood trees
take many years to grow, so can be difficult to
replace.
 Farming is estimated to be responsible for 25
percent of the Amazon forest being cleared.
 Fertile soils that make farming possible are
quickly washed away when the forest is cleared
for farming, mining or transportation.
 Loss of animal habitat occurs when trees are cut
down and animals that live in them have to find
somewhere else to live. Hence, deforestation can
result in endangering animals and plant life, or
even causing them to become extinct.
 Profits from large-scale farming and selling
resources often go back to MEDCs or large
companies and don't benefit rainforest
communities.
Why are rainforests important?
Rainforests are extremely important
in the ecology of the Earth.
85% of the planets plants and animals live in the Rainforest.
Remove the trees and most will die out.
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
We need the trees for paper, wood, furniture etc