topic 1B

• Example of a small-scale ecosystem: freshwater pond 

  Consists of pond bottom, mid water, surface, pond margin, above surface, Margin provides shelter for insects. Pond surface allows fish to prey on insects like dragonflies. Decomposers live on the pond bottom. Balance between components Introduction of more fish means the kingfishers thrive, but the number of caddis decrease due to more predators Fertilisers from fields draining into the pond may cause eutrophication. Increases algae but depletes oxygen
• Ecosystem


  A community of plants and animals that interact with each other
• Ecosystems

  • Tropical rainforests
  • Desert
  • Savannah
  • Tundra
  • Taiga
  • Temperate forest
• Factors that impact ecosystems

  • Droughts
  • Storms
  • Re-introduction
  • Deforestation
  • Climate change
• Droughts

  1. Producers won't be able to grow

  2. Fewer habitats available for animals

  3. Reduced food sources for consumers

  4. Soil will erode so nutrients will be lost
• Ecosystems

  • Interdependent - rely on each other for survival
• Tropical rainforests

  • Along equator
  • Humid
  • Rapid decomposition
  • Number of layers (forest floor, under canopy, main canopy, emergent layer)
• Deserts


  • Tropics of cancer and Capricorn
  • 1/5 of world's coverage
  • Dry and arid
  • Small selection of plants
• Abiotic factors

  • Sunlight
  • Soil
  • Water
• Storms


  1. Flooding can destroy plants and shrubs

  2. Reduces number of producers

  3. Animal habitats are disrupted, they are less likely to mate

  4. Lightning strikes lead to wildfires
• Savannah

  • Between 15-30 degrees north and south of equator
  • Hot all year round
  • Wet season for 6 months
  • Humid
• Biotic factors

  • Animals
  • Plants
• Re-introduction

  • Endangered species can be bred in captivity and released into the wild, e.g. grey wolves in USA
  • It can be used to increase biodiversity
• Tundra

  • Arctic circle
  • A plane with no trees
  • Plants close together
  • Cold
• Producers (plants)

  Produce their own food, and are at the start of the food chain
• Taiga


  • Near the poles
  • Cool temperate climate
  • Lots of evergreen
• Deforestation


  1. Fewer trees

  2. Soil erosion, producers don't/can't grow

  3. Reduces number of habitats available

  4. 80% of amazon rainforest live in the canopy trees
• Consumers (animals)


  Get their energy from other living things
• Temperate forest

  • Between 25-50 degrees north and south of the equator
  • Mild temperature
  • Wet
• Climate change

  1. More tropical storms and flooding

  2. Temperature changes which animals aren't used to, less adapted animals die reducing biodiversity
• Decomposers (fungi, bacteria)


  Take waste nutrients from the ecosystem and put them into the ground e.g. urine/dead animals
• Food web


  A complex hierarchy of plants and animals relying on each other for food. Made of many food chains.
• Food chain


  The connection between different organisms that rely on one another as their food source. Single flow of energy
• Nutrient cycle


  A set of processes whereby organisms extract the nutrients necessary for growth from soil or water, before passing them on through the food chain. Decomposers ultimately return these back to the soil.
• Tropical rainforests

  • Low air pressure
  • Lots of sun and rain
  • Lots of producers (photosynthesis)
  • Primary consumers have food
  • Can reproduce and use plants for habitats
• Nutrient cycling

  1. Dead and decaying matter falls from trees, plants or animals

  2. Returns to the soil to be decomposed

  3. Feeding nutrients to the soil
• The nutrient cycling process happens so fast due to the climate that only the top layers of the soil are fertile
• Deforestation


  Soil erosion will occur
• Soil erosion leads to the soil being infertile as the top layer of soil would blow/wash away and that is where all the nutrients are
• Tropical rainforest climate

  • Consistent all year
  • No seasons
  • Very wet (>2,000 mm per year)
  • Very warm (average temp. 28°C)
• Tropical rainforest soil

  • Latosol (red as rich in iron)
  • Infertile (heavy rain leaches nutrients)
  • Some nutrients on surface (Decomposition)
• Tropical rainforest structure

  • 4 layers: Emergent
  • Upper canopy
  • Lower canopy
  • Shrub layer
• Tropical rainforest biodiversity


  • Very high, but at risk due to deforestation
  • Over 50% of all the species in the world
• Tropical rainforest plants

  • Evergreen as continual growing season
  • Tall trees
  • Dense canopy blocks light
• Nutrient cycling


  Very rapid due to the hot and humid conditions
• Forest floor


  • Limited light
  • Few plants
  • Many thick tree roots
  • Small insects survive feasting on decaying material
  • Dark, warm and damp perfect conditions for decomposition
• Under canopy


  • Plants and trees have less growth (not a lot of sun)
  • Consists of bushes and shade loving trees
  • Animals here would be too heavy to live in the canopy
  • Not a lot of food
  • Not a lot of trees to provide habitats for large animals
• Canopy layer


  • Plants have large, pointed leaves that allow rain to fall off them, so they don't break under the weight
  • Many animals here have methods of camouflage to protect themselves from predators
  • Animals are good at flying/climbing
  • Layers below are shaded more (big leaves) therefore less photosynthesis
• Emergent layer


  • Plants need to be strong and hard wearing to withstand the wind and rain
  • Often have small leaves
  • Animals are usually small with flying/climbing skills
  • Heavier animals couldn't be supported by the trees
  • Trees grow tall in this layer as they have so much light, they can photosynthesise a lot and grow
• Economic development is important for the countries that house the Amazon as most of them are either LIC’s or NEE’s. 

  Higher demand for resources and money-> pressure to develop