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Geography
Tropical rainforestTropical rainforest
GeographyTropical Rain Forest
Geography
Rain Forest Family ForeverUnited Streaming 13:28
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Geography
-found near the equator
-temperature varies little from approximately 23°C
-the length of daylight varies from 12 hours by less than one hour
-rainforest>2000mm
Tropical Rain Forest
Geography
How many species are lost from tropical forests annually?
Over 20,000
How big is the Amazon Rainforest?
Half the size of the USA
6% of the land area on Earth but has over 50% of its organisms
Geography
Rainforests are home to over 50% of the world’s species
Brazil has the world’s largest total tropical rain forest acreage
Many acres are cleared to raise cattle.
There is now 50% less rain forests that 50 years ago.
Geography
Effects of DeforestationEffects of Deforestation
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GeographyTropical Rain Forest
-canopy trees up to 55 m tall
-largest biome, on an area basis
-soils are generally unfertile
-nutrients and carbon stored in plant biomass, not soils
GeographyTropical Savanna/Seasonal Forest
Geography
-found in the tropics (but > 10° latitude)
-pronounced dry seasonwith <5 cm rainfall in some months
Tropical Savanna/Seasonal Forest
Geography
Strong scent and bright colours of flowers attract insects which assist in pollination
Strong scent of fruits attracts animals, which feed on the fruit and assist in dispersal of the seeds
Thick, waxy surface of leaves protects against hot sun, heavy rain, and strong winds Aerial roots of
epiphytes absorb moisture from the air
Tall straight trunks no side branches
Thin, smooth bark
Buttress roots Shallow spreading root system
Geography
Orchid - sun-loving roots attached themselves to branches and absorb nutrients
Pitcher plant - a carnivorous plant.
slippery rim
tendril
Insects falling into the pitcher are digested, and nutrients which are released are absorbed by the plant.
Parasitic plant
GeographyStructure of the rainforest
The dominant plants in a rainforest are giant trees. The hot wet climate enables them to grow all year round, and they remain evergreen, continuously shedding their leaves and growing new ones.
The average height of rainforest trees is about 45 metres, although the emergence (trees which tower above the others) may go as high as 90 metres. Smaller trees growing the under story (layer between the canopy and the forest floor).
Several layers can be identified within the forest
Geography
Rainforest plants And the enormous the number of different species of plants grow in rainforests, with many species occurring only in one particular region. Unlike other forests, rain forests have an abundance of :
Epiphytes plants which live above the ground growing on tree trunks and branches, Example orchids,
ferns, mosses
Climbing plants including large woody climbers called lianas which are rooted in the soil and usually reach thecanopy. The climbers twist around the tree trunks, and loop from one tree to another in the canopy, binding the trees together.
Geography
Tom Abbott, Biddulph High School and made available through www.sln.org.uk/geography and only for non commercial use in schools
A Emergent tree canopy
B Large trees of Middle layer
C Lower tree layer
D Shrub/small tree layer
E Ground vegetation
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GeographyCanopy layer - formed by the crowns of the tall trees and contains a mass of branches, Leaves, flowers and fruit. Conditions in the canopy vary, and include: •Hot sunshine •Heavy rainfall •Tropical storms
Middle layer - the Vegetation here is more sparse. The trees tend to have pointed crowns and, when a giant tree falls, they grow quickly to fill a gap in the canopyConditions within the forest on more or less constant: •There is little variation in temperature •The air is moist and still •Rain on the canopy drips to the forest floor several minutes later •A breeze is rare, even during storms
GeographyON THE FOREST FLOOR
Shrub layer - scattered shrubs, saplings (young trees) and ferns.
Herb layer - a few non-woody, soft stemmed plants with thin leaves.
Leaf litter - thin layer covers the forest floor.
Soil layer - most roots growing the top 10 centimetres whether nutrients are found.
Geography
Wealth of the Rain Forest
The Amazon Rainforest has been described as the "Lungs of our Planet" because it provides the essential environmental world service of continuously recycling carbon dioxide into oxygen. More than 20 percent of the world oxygen is produced in the Amazon Rainforest. More than half of the world's estimated 10 million species of plants, animals and insects live in the tropical rainforests. One-fifth of the world's fresh water is in the Amazon Basin. One hectare (2.47 acres) may contain over 750 types of trees and 1500 species of higher plants.
At least 80% of the developed world's diet originated in the tropical rainforest. Its bountiful gifts to the world include fruits like avocados, coconuts, figs, oranges, lemons, grapefruit, bananas, guavas, pineapples, mangos and tomatoes; vegetables including corn, potatoes, rice, winter squash and yams; spices like black pepper, cayenne, chocolate, cinnamon, cloves, ginger, sugar cane, tumeric, coffee and vanilla and nuts including Brazil nuts and cashews.
GeographyRAIN FOREST IS A MEDICINE CABINET
Rainforest plants are rich in secondary metabolites, particularly alkaloids. Biochemists believe alkaloids protect plants from disease and insect attacks. Many alkaloids from higher plants have proven to be of medicinal value and benefit.
Currently, 121 prescription drugs currently sold worldwide come from plant-derived sources. And while 25% of Western pharmaceuticals are derived from rainforest ingredients, less than 1% of these tropical trees and plants have been tested by scientists.
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Geography
The U.S. National Cancer Institute has identified 3000 plants that are active against cancer cells. 70% of these plants are found in the rainforest. Twenty-five percent of the active ingredients in today's cancer-fighting drugs come from organisms found only in the rainforest.
Vincristine, extracted from the rainforest plant, periwinkle, is one of the world's most powerful anticancer drugs. It has dramatically increased the survival rate for acute childhood leukemia since its discovery
Geography
In 1983, there were no U.S. pharmaceutical manufacturers involved in research programs to discover new drugs or cures from plants. Today, over 100 pharmaceutical companies and several branches of the US government, including giants like Merck and The National Cancer Institute, are engaged in plant research projects for possible drugs and cures for viruses, infections, cancer, and even AIDS