Transcript tropical rainforest,2014 - GE-sec2i-2014

TROPICAL
RAINFOREST
PAGE 37-43
OBJECTIVES
• Describe and explain distribution
of tropical rainforest.
• Describe the features of tropical
rainforests.
• Describe how tropical rainforest
adapt to the environment.
OVERVIEW
DISTRIBUTION
ADAPTATIONS
TROPICAL
RAINFOREST
PLANTS
STRUCTURE
RAINFOREST
DISTRIBUTION
Location of tropical rainforests
Location of tropical rainforests
DISTRIBUTION
• Found in places between 10°N and 10°S of the
Equator
• Mainly located in Amazon Basin, Congo Basin,
and parts of Southeast Asia such as Malaysia
and Indonesia.
DISTRIBUTION
DISTRIBUTION
• Why?: high temperatures (27°C) and high
rainfall (above 1500mm) throughout the year.
• This promotes abundant plant growth which is
typical of tropical rainforests.
RAINFOREST
STRUCTURE
PAGE 38
STRUCTURE
• 5 distinct layers: Emergent, Canopy,
Understorey, Shrub, Undergrowth
• [You are expected to label/ describe every
layer in detail]
STRUCTURE
• Emergent:
– 30-50m
– Tall trees (Emergent trees)
– Tall, thick, straight trunks
• Canopy
– 15-30m
– Wide, umbrella shaped crowns
– Continuous leaf cover called canopy
STRUCTURE
• Understorey
– 6-15m
– Narrower, oval-shaped crowns (?)
– Young trees of canopy, emergent
• Shrub
– 5m
– Tree saplings, woody plants
STRUCTURE
• Undergrowth
– 0-5m
– Grasses, ferns, mosses, fungi
– Sparse growth (?)
RAINFOREST
CHARACTERISTICS
PAGE 40-43
C#1
• The undersgrowth in a tropical rainforest is
sparse.
• This is because, little sunlight
RAINFOREST
FEATURES
#1: Sparse Undergrowth
• There is sparse undergrowth in the forest floor
of the tropical rainforest.
• This is because very little sunlight (about one
percent) passes through the canopy and
reaches the forest floor.
#2: Large Variety
• There is a large variety of plants in the tropical
rainforest. It is estimated that rainforests may
contain more than 750 species of trees and
1500 species of other plants.
• This is because of consistent high temperature
and rainfall throughout the year that promotes
plant growth.
#3: Extreme density
• Tropical rainforests are extremely dense due to
the presence of a large variety of plant species
which can grow in the tropical rainforest.
#4: Evergreen Leaves
• Tropical rainforests have evergreen leaves due
to the consistently high rainfall throughout the
year.
#5: Large & broad leaves
• Tropical rainforests have large and broad
leaves to maximise the surface area for
photosynthesis.
#6: Thin & smooth barks
• Tropical rainforests have developed thin and
smooth barks because there is no need for
protection against cold or dry conditions.
#7: Buttress Roots
• Some trees in the tropical rainforest have
buttress roots, which are thick and spread out
widely to support the great weight of trees.
RAINFOREST
ADAPTATIONS
#1: Low Light
• The canopy layer prevents sunlight from
reaching the lower layers of the tropical
rainforests.
• Some plants such as the epiphytes and lianas
have adapted to this low light condition by
growing on tree branches.
• Furthermore, these trees have branches only
on the top one-third portion of the trunks
to get maximum sunlight.
#2: Bacteria Growth
• High temperature and high rainfall in the
tropical regions promote rapid growth of
bacteria.
• Hence, tropical rainforest have waxy leaves
with drip tips to allow rainwater to drain off
easily.
• This prevents harmful bacteria from growing
and protects the plants from diseases.
#3: Still air below canopy
• The presence of the continuous canopy results
in still air in the layers below it and this does
not allow pollination to be carried out by wind.
• Hence, flowers and fruits in the tropical
rainforest are colourful and sweet-smelling.
• This attracts insects for pollination and animals
for seed dispersal.
#4: Rapid humus formation
• High temperatures and rainfall all year round
causes the leaf litter to decompose and form
humus rapidly.
• This supplies nutrients to the topsoil, which is
the uppermost layer of the soil.
• Hence, the roots of trees in the tropical
rainforest are shallow and spread widely
to absorb the nutrients present in the topsoil.
RAINFOREST
PLANTS
EPIPHYTES
• This refers to plants that grown on and use
trees for physical support.
• Rainwater and decaying leaves provide the
epiphytes with water and nutrients.
• Example: Bird’s Nest Fern, Orchids
LIANAS
• Refers to thick, woody vines that wind around
tree trunks to reach for sunlight
PARASITIC PLANTS
• This refers to plants that compete with the host
tree for space, sunlight and nutrients.
• These plants are common in the canopy and
understorey layer of the rainforest.
• Example: Strangling Fig
SUMMARY
DISTRIBUTION
ADAPTATIONS
TROPICAL
RAINFOREST
STRUCTURE
PLANTS
Complete Review
Worksheet #2