2. Rainforests
► Rainforests are one of
the important biomes
on the earth.
► Rainforests are found
where there is a lot of
precipitation
So it is very wet
4. Tropical Rainforests
► Today most tropical rainforests are found in
Central America
The Amazon Basin in South America
Africa
Southern Asia
Australasia
5. Tropical Rainforests and Biodiversity
► More species of animals and plants live in
tropical rainforests than any other place on
earth.
Although tropical rainforests cover only about
6% of the earth’s surface half of the animal and
plant species found on earth live in tropical
rainforests!!!!
6. What is it like in the tropical
rainforest?
► When the environment is wet and warm there
are almost perfect conditions for plant growth.
► Tropical rainforests have lots of plants!!!
7. Brief Review of Plants
► You get the energy and nutrients that you need
from the food that you eat and the water that you
need by drinking.
► Plants don’t eat or drink, so how do they get their
nutrients, energy, and water
Get energy from the sun
► Photosynthesis turns energy in light to energy in sugar
Get nutrients and water from the soil
► Pick up nutrients and water from the soil using their roots
8. Rainforest trees can be very tall
► Because there is so
much water, plants are
able to grow very tall.
► The tallest plants are
able to grow up to
where there is lots of
light.
► Shorter plants must
grow in the shade.
9. Rainforest Layers
► There are many
different layers of
plants in a tropical
rainforest.
10. Emergent Layer
► The emergent layer is
made up of the tallest
trees that grow larger
than any of the other
trees.
► Can be over 80 meters
tall.
► It is good to have your
leaves in the emergent
layer because there is
lots of sunlight
11. Canopy
► The canopy layer is
where most of the
leaves in a tropical
rainforest are found.
► Very dense vegetation.
13. Understory
► Shorter plants living in
the understory of the
emergent and canopy
layers do not get as
much light so they
have to be able to
grow in the shade.
Only about 1% of the
sunlight reaches the
understory level.
14. Forest Floor
► The forest floor is
covered with dead
leaves.
► These dead leaves will
decompose (rot) and
return the nutrients
that they contain to
the soil.
15. Nutrient Cycle
Rainforest trees
Dead leaves and wood
decomposers
Soil
Plants pick up nutrients from the soil with their roots. When leaves die, they carry
nutrients with them as they fall to the ground. Decomposers such as fungi
break down the dead leaves and return the nutrients to the soil.
16. Decomposers
► Decomposers such as
fungi break down dead
material and return
nutrients to the soil.
► Because fungi grow
best when it is warm
and wet,
decomposition occurs
quickly in tropical
rainforests.
18. Woody Trunks
► In order to reach the
emergent layer, plants
must grow very tall
► Tall plants must have
strong woody trunks in
order to support the
growth
Costs lots of energy and
resources to make large
woody trunks
► Lots of wood in tropical
rainforest
That’s why foresters like to
cut down rainforests
► Lots of wood
19. Buttress Roots
► Tallplants (emergent
layer) are so tall that
they are unstable and
are at risk of falling
down
► Some plants have
buttress roots
Large roots that spread
out and help support
the tree from falling
over
20. Lianas
► It costs a lot of
resources for plants to
make woody trunks to
support their leaves in
the emergent and
canopy layer
► Lianas (vines) use
other trees to support
their growth
22. Epiphytes
Epiphytes grow attached to other trees
in the rainforest.
They do not have to pay to make all of
the wood that would be needed to let
them grow so high above the ground.
Epiphytes are very common in tropical rainforests.
23. Leaves
► Environmental conditions vary greatly
between plants living in the emergent layer
and those living in the understory
Emergent layer
►Bright sunlight, very windy
Understory
►Shade, calm
24. Leaves
Emergent and canopy leaves are Understory leaves are large because
small because they get lots of light. they live in the shade.
25. Pollination
► Flowers of rainforest
plants are pollinated by
a variety of animals
including insects, birds,
and bats.
26. Rafflesia
► Rafflesia, the largest
flower in the world,
can be almost 3 feet in
diameter
Found in Malaysian
rainforests
► These beautiful flowers
smell like rotting meat
which attracts the flies
and beetles that act as
pollinators.
27. Seed Dispersal
► Many plants in the
tropical rainforest
produce fruits to
attract animals to act
as seed dispersers
The animals consume
the seeds when the
animal eats the fruit but
the seeds get passed
out through the animals
gut.
28. Seed Dispersal
► Because they produce ► Because they live
seeds where there is where there is little
lots of wind, emergent wind, plants in the
trees produce seeds understory produce
that are dispersed by seeds that are
the wind. dispersed by animals.