3.2.2 - the structure and functioning of ecosystems

What does an ecosystems being self regulating mean

They require no human intervention to be able to survive

What are biotic elements

Living components

What are abiotic elements

Non living components

What is a tropic pyramid

It shows the distribution of energy and biomass across the different tropic levels within an ecosystem

What is the species found that tropic levels one

Produces which are also known as autotrophs as they produce their own food through photosynthesis

What is the species at the second trophic level

Herbivores which are primary consumers as they get their energy from eating plants

What species is at the third trophic level

Carnivores which get their energy from eating both animals and plants

What species is at the fourth trophic level

Omnivores which get their energy from carnivores herbivores and plants (also known as heterotrophs)

What is the 10% rule

The idea that only 10% of energy is passed on as you move up the level as most of it is lost due to things like respiration and movement

What is a detritivore

An organism e.g. snails or worms which feed on the dead decaying matter and they are at each level of the trophic pyramid

What are detritivores also known as

Saprotrophs

What will happen if producers decrease to a point where they are less than the herbivores

The whole ecosystem will collapse because there isn’t enough food to source each species

What are human or natural activities that lead to a reduction is producer numbers

• deforestation for urbanisation

• Diseases

• Climate change

What is an apex predator

The top predator in the food chain

What is biomass

The total mass of all living material within an ecosystem

What are nutrients

Chemical elements and compounds needed for organisms to function and grow

Give examples of nutrients that are needed

• Calcium

• Nitrogen

• Phosphorus

• Magnesium

• Potassium

Give examples of biotic features in an ecosystem

• cows

• Trees

• bacteria

Give example of abiotic features in an ecosystem

• nitrite

• Clouds

• Sunlight

• Precipitation

Give examples of inputs into the system

• rainfall

• Weathering

Give examples of outputs in the system

• surface runoff

• Leeching

Give examples of nitrogen flows in an ecosystem

• rain input

• Fine litterfall (leaves)

• Weathering

What is nitrogen fixation

When nitrogen is absorbed by the leaves on trees from the atmosphere

How does deforestation affect the nutrient cycle

• When trees are removed the nutrients in the roots and the tree and permanently removed from the soil and can’t be replaced

• It will increase things like leeching and soil erosion so then the nutrients in the soil are washed away

Give an example of management techniques for deforestation

Selective felling

What is selective felling

When some trees in the areas that are being deforested are being left behind so then they can regrow and the nutrient cycle isn’t affected too badly

Give 2 examples of how nitrogen is cycled in a system

• Nitrogen is taken from the atmosphere and absorbed by the leaves of trees

• Fine litterfall allows nitrogen to fall from trees

How does soil compaction affect nutrient cycle

It’s caused by heavy machinery and logging which may kill roots and therefore rapidly reducing nutrient absorption

How does agriculture affect nutrient cycling

Conversion of rainforest into arable crops disrupts the nutrient cycle due to constant cultivation and artificial fertilisers

What are arable crops

Crops that are for food e.g. wheat

What is the optimal range for biomass growth with precipitation

0-2000 mm

What is the optimum temperature for biomass growth

0-20 degrees