Section B Living World

• Ecosystem


  A natural system made up of plants, animals and the environment
• Biotic components


  Living organisms of ecosystem e.g. plants, bacteria and fungi
• Abiotic components


  Non-living chemical and physical factors in the environment e.g. sunlight, carbon dioxide, rock type and rainfall
• The nutrient cycle


  The circulation of nutrients between abiotic (non-living) and biotic (living) parts of ecosystems

  
• Litter layer


  The dead material on the ground
• Plant take up


  Nutrients taken up by plant roots - creates biomass
• Fall out


  Material dies/ 'falls out' of the food web
• Decomposition


  Done by decomposers break down of dead organic material
• Weathering of rock


  Break down of rock by chemical/biological weathering
• Leaching


  Loss of nutrients by heavy rain
• Soil


  The store of nutrients
• Examples of a small scale ecosystem

  Woodland or freshwater pond
• What is a global ecosystem known as and what is an example?

  Biome e.g. tropical rainforest
• Latitude


  Distance north or south of the Equator, measured in degrees

  
• Altitude


  Height above sea level
• Factors that affect biomes

  - Distance from the sea

  - Ocean currents

  - Prevailing winds
• Producers


  Organisms that make their own food by converting energy from the environment into sugars
• Consumers


  An organism that obtains energy and nutrients by feeding on other organisms or their remains.

  Classified as primary, secondary, tertiary etc
• Decomposers


  Organisms that break down wastes and dead organisms and return raw materials to the environment e.g. fungi and bacteria
• Where are rainforests found?

  Tropics of cancer and Capricorn, mainly at the Equator.
• Structure of the rainforest

  Litter layer

  Shrub layer

  Under canopy

  Main canopy

  Emergents

  
• Litter layer of rainforest

  Ground layer made up of dead and decomposing materials
• Shrub layer


  Made up of plants which can tolerate a lack of light.

  Up to 10m high
• Under canopy


  Younger trees waiting for the a gap inside the canopy. The light restricts their growth to about 10-20m
• Main canopy


  A thick layer of mature trees about 20-30m tall. This is where most life and light is in the tropical rainforest
• Emergents


  Made up of the tallest and oldest trees between 30-50m tall. They rise above the main forest
• What ecosystem has the highest biodiversity?

  The rainforest has the highest because of the amount of heat (27C), water (20,000mm a year), and sunlight in the rainforest.
• Key facts about the Amazon Rainforest.


  - South America

  - Home to over 3 million species of plants and animals

  - Home to 50% of all species of Earth
• Adaptations of drip tips

  - Waxy pointed ends

  - Cope with high levels of rainfall

  - Rain falls to the floor to be absorbed by the roots

  - Stops damage to the leaf under the weight of rain
• Adaptations of buttress roots

  - Wide triangular bases

  - High temp and rainfall make perfect growing conditions

  - Grow 30m tall

  - Wide base keeps them stable
• Adaptations of liana


  - Grow up trees/vines

  - Don't have to compete for sunlight = able to photosynthesise
• Examples of medicines found in rainforests

  Novocaine, quinne (treats malaria), coritone (birth control tablets) and slime secretions from frogs used to treat infections and HIV
• Sustainablility


  Meeting our needs without compromising the needs of future generations
• Rubber tapping


  Latex is collected from a rubber tree. A cut is made in the tree's bark which allows the sap to seep out naturally and to be collected. Then the opposite side will be tapped which allows the other side to heal.

  
• Cattle ranching


  Clears the forest to graze cattle for beef. It's the biggest cause of deforestation. It is responsible for the release of 340 million tons of carbon every year. After, the land is so degraded that the forest can't regrow

  
• Dams/HEP


  Building of dams has led to flooding.

  The Itaipu dam is 7km long and cost $18 billion to build. These are used to generate hydroelectric power, can use less fossil fuels. 60,000 people had to be moved from their homes in the area flooded.

  There are 158 dams in the Amazon

  
• New Roads


  The government of Brazil set up road building schemes to make exploiting the Amazonian region easier.

  It is 4,000km long and is the third longest highway in Brazil.

  Amazon has nearly 100,000km of roads.

  
• Mining


  There are rich deposits of iron core, bauxite, manganese, copper, tin, gold, diamonds and other minerals.

  They have excavated to a depth of 250m

  
• Logging


  17% of the Amazon has been destroyed.

  Mahogany and teak are the most desirable trees and 30 trees may be destroyed just to get one of the tropical hardwoods.

  
• Settlement


  The population of Amazonia has increased by over 30 million in the last 110 years. It encouraged people to move from the Favelas. They would receive a lot just over 1km2 in size, 6 months salary and agricultural loans.

  However, the soil was poor and lack of education meant that many turned to illegal logging.