Tropical Rainforest Tropical Rainforest BiomeBiome

Tropical Rainforest Tropical Rainforest BiomeBiome

• 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

• 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%• Transpiration increase water • vapour and high temp increases • 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– Emergent, – Canopy, – Understory, – Forest floor

• Emergent – – 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– 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 light-

little 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)

• Highly diverse• Chameleon, • jaguar, • gorilla, • macaw, • sloth, • forest elephant

• 100 species per hectare• 6km2 –

– 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

• Insects, spiders, birds, monkeys,

• 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• Poison arrow frog and snakes

– • 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– (Kapok is an emerger so it needs

wide – 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

• Cattle ranchers invading and • deforesting in eastern fringe