geography

• an ecosystem is a natural system made up of plants, animals and the environment.
• global ecosystems are called biomes
• biotic means living
• abiotic means non-living
• producers convert energy by photosynthesis into carbohydrates for growth
• consumers get their energy from eating producers and decomposers
• dead plant and animal material is broken down by decomposers to add to nutrients this is called the nutrient cycle
• slow natural changes to the environment have few harmful effects
• rapid changes make serious impacts
• human activities can have many impacts on ecosystems
• biomes are defined by one dominant type of vegetation
• the climate and characteristics of ecosytems are determined by global atmospheric circulation.
• the tundra is mainly located between the arctic circle to about 60-70 degrees North and have cold, windy and dry conditions
• deciduous and coniferous forests are located 50-60 degrees north and have got a colder climate.
• temperate grassland are located 30-40 degrees north and south of the equator and always inland. they've got warm, dry summers and cold winters.
• mediterraneon are located south of the equator and have hot, sunny, dry summers and mild winters
• desert covers one fifth of the earths land and have high daytime temperatures and low night time temperatures with very low rainfall.
• tropical rainforests covers 6% of the earths land surface mainly close to the equator and has high temperatures and heavy rainfall
• tropical grasslands (savanna) are located between 15-30 degrees north and south of the equator and have distinct wet and dry seasons.
• polar located north and south poles with low temperatures (-50) and dry conditions
• tropical rainforests are found a few degrees either side of the equator between the tropics
• the majority of nutrients in a cycle are stored in biomass and a few nutrients are stored as litter due to rapid decomposition and few nutrients are stored in the soil this is the nutrient cycle
• tropical rainforests support more than 50% of all living organisms
• lianas - lets lightweight animals to travel in the lower canopy
• straight branchless trunks to fight for the most light in top canopy (35-50m)
• drip tips to shed water quickly in the most productive layer the middle canopy (20-35m)
• ground layer (0-10m) with thick buttress roots to hold the weight of the trees
• 
  

  deforestation - cutting down of trees and replacing with agriculture etc
• water pollution - mining which poisons rivers
• climate change - deforestations reducing evapotranspiration causing climatic drying
• malaysia has one of the highest rates of deforestation in the world.
• malayasia clear the equivalent to a football pitch every 4 mins and lost 16% of its primary rainforest between 2002 and 2018
• around 50 million indigenous people live in the worlds tropical rainforests
• 25% of the worlds medicine was produced in rainforests.
• vampire bat saliva - prevent heart attacks

  quinine - treats malaria