Ecosystems are communities of living (biotic) and non-living (abiotic) organisms in conjunction- complex natural systems of plants & animals with the environment. From as small as a garden pond to as large as a biome. 

They have complex interrelationships between biotic features and abiotic environmental factors.

Ecosystems work because they have a flow of energy and a cycle of nutrients through them.

Ecosystems are important because :

  • Without them, the world would lack diversity in the flora and fauna.
  • Plants & Animals have evolved to depend on each other so if a certain species was irradicated then it would have a damaging knock-on effect on the rest of the environment.

Trophic levels (energy flow):

  • Producers (plants) convert the suns energy into food for the consumers.
  • Primary consumers (herbivores) eat the producer and gain energy however it does release some metabolic heat. 
  • Secondary consumers (carnivores) that eat the primary consumers.
  • Tertiary consumers carnivores that are at the top of the food chain - Apex predators - they have no predators.

Dead plant and animal material are broken down by Decomposers (bacteria and fungi) which adds nutrients to the soil which the plants can then reuse. - The nutrient cycle

Nutrients are in the Biomass (trees) and their leaves which fall off in autumn a process called littering as the leaves then become litter on the ground. The nutrients in the leaves are then broken down by decomposers (Bacteria & Fungi) in a process called Decomposition. The nutrients are now converted into humus in the soil which creates nutrient-rich soil which is great for supporting the plants. Roots take the nutrients from the soil and re-use it in the biomass a process called Plant uptake

An example of a small-scale ecosystem is a garden pond 

An example of a large-scale ecosystem is a rainforest

Ecosystem - Producer -> Primary consumer -> Secondary Consumer -> Tertiary Consumer

  • Pond:         Water Plants ->  Mayfly larvae ->  Dragonfly -> Kingfisher
  • Sand Dune:  Marram grass ->  Grasshopper ->  Opossum -> Wolf
  • Rainforest:   Banana tree ->  Monkeys ->   Jaguar

Epping Forest: northeast of London, south of Stanstead airport with M11 &M25 through it.

Producers in Epping forest are Deciduous trees, shrubs mosses and ferns which are eaten by the primary consumers: Rabbits and Insects.


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