Ecosystems

Question 1

What is an ecosystem?

Answer 1

• An ecosystem is the living (biotic) and non-living (abiotic) components of an ecosystem
• A small ecosystem could be a garden pond
• A large-scale ecosystem could be all tropical rainforests - this is known as a biome
• Biodiversity refers to the variety of plant and animal species within an ecosystem
• The level of biodiversity depends on the climate, available habitats and food sources

Question 2

What is interdependence?

Answer 2

• Within an ecosystem, the different biotic components depend on each other, and the abiotic components for survival (food, water and shelter)
• It means that changes in one component can have significant impacts on other parts of the ecosystem
• These interactions can be shown as food chains and food webs

Question 3

Food webs and chains

Answer 3

• **Producers: **Food chains always start with a producer
• Primary consumers: Producers are eaten by primary consumers (herbivores/omnivores)
• Secondary consumer: Primary consumers are eaten by secondary consumers (carnivores/omnivores)
• Tertiary consumer: Secondary consumers are eaten by tertiary consumers (carnivores/omnivores)
  There are also decomposers.

These are fungi and bacteria, and they:
-Help to return energy/nutrients back to the soil
-Break down dead organic matter plant/animal waste
-Release energy from organic matter so it can be recycled

Question 4

What is Ecosystem Balance?

Answer 4

• A stable ecosystem is one where all the biotic and abiotic components are in balance so that the populations remain constant
  Natural events may include:
  Wildfires caused by lightning
  Climate change (though it can be argued this is human-induced)
  Spread of invasive species
  Disease
  Extreme weather events: Flood or drought
  Human activities may include:
  Deforestation
  Hunting of animals/birds
  Hedgerow removal
  Changes to water supply/drainage patterns or temperature
  Addition of chemicals: Fertilisers