Transcript Forest Biome

Tropical Rainforest
Biome
• What: Biomes are unique regions of the
world where the climate controls what
type of soil forms there, animals life
there and plants grow there
• Where: The tropical Rainforest in
Amazon Basin
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What aspects: Climate,
Vegetation, Soils and Animals
• Climate
• 3 Largest Rainforsts, South America,
Africa, Asia
• 5 degrees N&S of equator
• Equatorial Climate
• Suns angle - 90° to 66°
• Direct sunlight – avg temp 27° - range 2°
• Highest temp 35°- lowest 24° due to
constant cloud cover
• Feels hotter due to high humidity – up to
88%
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Transpiration increase water
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vapour and high temp increases
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airs ability to hold water
• Rainfall always in excess of 2500mm
up to 6600mm in sumatra
• Rain is in short heavy downpours
• Strong winds shake the canopy
• Short term flooding but quickly soaks
away
• Amazon Basin – Ecuador, Venezuela,
Peru, Bolivia and Brazil
• Congo Basin, Indonesia, Northern Aus
•Soil
• Latsol – Tropical Rainforest
• Poor nutrients due to leaching by heavy
rains
• Red in colour due to oxidation of Iron
• Very short nutrient cycle
• Nutrients found in living plants &
decomposing plant litter ( O Horizon)
• High Humidity and insects, bacteria ad
fungi convert to humus quickly
• Plants absorb instantly – 99% of nutrient
held in plant roots
• 5-8% of sunlight reaches forest floor –
undergrowth deprived of energy source
• Secondary enrichment – creation of small
mineral rich deposits
– Chemicl weathering and percolating water
concentrate amounts of precious metals e.g.
Bauxite
– Formed by leaching, common elements removed
e.g. Calcium, silicon etc. Aluminium extremely
insoluble so concentrates at surface as bauxite
– Also occurs with Iron, soluble iron is washed
down and concentrated as haematite
• Plant Life (Flora)
• 4 layers
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Emergent,
Canopy,
Understory,
Forest floor
• Emergent –
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80m,
far apart,
umbrella shape above canopy,
smallpointed leaves as exposed to strong wind
Straight smooth branchless trunks
Butress roots (up to 9m) to support height
Hardwoods e.g. Teak & Mahogany
• Canopy
– 20-40m
– Thick lianas and epiphytes like mosses and
orchids
– Orchids get inorganic nutrients from air and
rainfall and live perched on branch joints
– Plant have leaves that can gather water in
downpours but have drip trips to discard it
before it becomes stagnant
– Some leaves can turn towards sun to absorb
maximum sunlight
• Understory
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Less than 3% of light reaches
Dark environment
Limited growth
Short, leafy, non flowering shrubs,
ferns and vines
– Adapted to filtered light and poor soil
• Forest Floor
– Such limited light –less than 1% of lightlittle growth
– Poor thin soils
– Dense vegetation where gap in canopy –
trees have fallen
– Lianas cling to branches of young plants
– Only most vigorous plants survive
• Large fleshy fruits develop on trunk rather than
branch tips so animals can reach them
• Epiphytes are plants that live on stronger plants –
depend on air to bring them moisture and
inorganic nutrients e.g. Orchids
• Lianas – wood vines, start as small shrubs and
grow up tree trunks – make up 40% of canopy
leaves
• Fauna (Animal Life)
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Highly diverse
Chameleon,
jaguar,
gorilla,
macaw,
sloth,
forest elephant
• 100 species per hectare
• 6km2 –
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1500 plant species
750 tree species
400 bird species
250 butterfly species
100 reptile sepcies
• Larget Animals on ground floor e.g. Gorillas,
Anteaters, wild boars
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Insects, spiders, birds, monkeys,
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reptiles and amphibians life canopy
Adaptations:
• Birds have big beaks to break nuts and tough
shells e.g. Toucan & Parrot
• Ability to live in trees
• 27% of worlds bird species live there
• Bright colour deflect heat and attract mates
during mating season
• Loud vocalisation- easy to communicate in
dense vegetation
• Diets heavy on fruit
• Camouflage – one adaptation of animals
• E.g. Like a leaf
• Moths and insects look dead or like leaves
to hide in foliage
• Abundant insects that in danger from
predators e.g. Stick insects and tree frogs
• Animals use colour to warn predators but
some are bluffing
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Poison arrow frog and snakes –
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bright colour means danger
• Body structure:
• Flying foxes – flap between front and back
legs that allow it to glide long distances
• Tail can wrap around trees for support
(prehensil tail) e.g. Lemur
• Sloths are covered in green algae that
make them very hard to see
• Tree trunk environment
– Woodpeckers drill holes in dead trees – easy
and soft
– Holes used as nests
– Living trees also used as the sap acts as
irritant for snakes trying to reach nest
– Monkeys and birds also use these holes
• Pollination
– Plants use nectar to attract insects to aid
pollination
– Kapok have fluffy tops that are dispersed by
the wind
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(Kapok is an emerger so it needs wide
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dispersal to survive)
Yanomami Tribe
• 32,000 in number
• 9.6m hectares
• Live in communal houses that sleep up of
400
• Men hunt – 10% of food intake
• Women farm – 60 crops up of 80% of food
intake
• Decisions by consensus – often long
debates
• 1940’s first contact with outsiders
– Measles and flu killed many
• 1970’s miliary govt built road through land
– 2 villages wiped out by disease
• 1980’s – 40,000 gold miner invaded and
20% of Yanomami died in 7yrs
• Now over 1000 gold miners working
illegally
• Malaria is being spread and mercury is
polluting rives
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Cattle ranchers invading and
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deforesting in eastern fringe