Download Chapter 9 - CMenvironmental

Chapter 9
Section 9.3
Rain Forests
Tropical Zone
• Located: near equator
• Direct rays of sunlight
• 25 degrees Celsius year long
• Growing season= 12 months
• Precipitation = 200-450 cm/ year
• Soil nutrients = limiting factors
Rainforest structure
• Most diverse terrestrial biome on
Earth
• Rain forest- biome with a dense
canopy of evergreen broadleaf
trees supported by at least 200 cm
of rain each year
Rainforest structure
• Contain 70% of all terrestrial
species on Earth
• Cover 6% of Earth’s surface
• Hold 50% of all biomass on Earth
• Great biodiversity
Rainforest structure
• Trees are the basis of this biome
• Thousands of species: cypress,
balsa, teak, mahogany
Rainforest structure
• Levels
–Emergent trees
–Upper canopy
–Lower canopy
–Understory
Canopy
• Captures 99% of sunlight
• Vegetation on the forest floor
is sparse
Forest floor
• Dead organic matter does
not last…why?
• HINT: Think of temperature,
organisms, etc.
Rainforest
• Matter is held in organisms
• Nutrients are in top 5cm of soil
• Tree trunks are wide at bases
(buttresses)- support trees
• Trees = shallow roots
• Epiphytes = plants live on trees’
trunks; get nutrients from trees
Organisms
• Arboreal = tree-dwelling, never
touch the ground
• Most organisms live in the tree
canopy
Diversity
• Animal diversity is available
because of:
• Diversity of plants
• Diversity of habitats
Habitats
• Vary from tree to tree or from
one part of the tree to another
• Species adapt and interact
with each other to survive and
reproduce
How many species?
• American biologist, E. O. Wilson
found 43 species of ants on just
ONE tree!
• Scientists do not have an exact
number, but they estimate there
are over MILLIONS of species in
the rainforest alone.
Deforestation
• 1950- 10% rainforests
• 2009- <6% rainforests
• Deforestation- destruction of
forest as a result of human
activity
Deforestation
• Trees are logged for lumber and
space
• Farms are built on new land, but
are unable to hold nutrients for
crops
• What do you think happens
next?
Deforestation
• Rainforest is vertical
ecosystem
• Why is this important
regarding deforestation?
Deforestation
• Rainforests may take 100+ years
to regenerate after it is disturbed
or burned.
• What are some problems with
this?
• How does this differ from the other
forest biomes?
REVIEW!!!
• Why do rainforests have
buttresses?
• What two factors make the
animal community in the rain
forest diverse?