A microorganism is an organism that can only be seen using a microscope.

A decomposer is an organism that feeds on the remains of other living organisms (organic matter).

A protein which acts as a biological catalyst. This speeds up a reaction without being used up.

The rate is how quickly something takes place. The rate of a reaction is a measure of how much change occurs per unit of time.

Factors affecting the rate of decomposition

Biology

Pupils will learn about biomass transfer including calculating the efficiency of transfers between trophic levels. They will learn about human impacts on the environment, food security and biotechnology to help maintain biodiversity and achieve food security.

Pupils learned about interdependence within ecosystems and how plants and animals are adapted to their environment. Pupils undertook ecological sampling to estimate population sizes and looked at the impact of humans on biodiversity.

Living organisms and their environments

Which factors affect the rate of decomposition?

Which of the following is an example of a biological catalyst?

As the temperature increases, the rate of decomposition increases.

As the temperature decreases, the rate of decomposition increases.

The rate of decomposition increases with temperature until enzymes denature.

As the temperature increases, the rate of decomposition stays the same.

Temperature affects the rate of decomposition. Which of the following statements is correct?

the rate of decomposition to stay the same.

When there is lots of oxygen present, the conditions are said to be {{}}.

Stirring the contents will release heat from the compost.

Stirring the compost will help to release moisture to the air.

Stirring the compost will help to provide more oxygen to decomposers.

Stirring the contents will make the compost wet. 

Why might stirring / turning over the contents of a compost bin increase the rate at which decomposition takes place?

What piece of equipment might you use to observe a microorganism?

Which of the following organisms are examples of decomposers?

When there is little or no oxygen present.

Biogas is a product of decomposition. It is formed by microorganisms that decompose organic waste under what sort of conditions?

They supply oxygen for plants to use in photosynthesis.

They keep the ecosystem clean by breaking down dead organic matter.

They provide herbivores with the food that they need.

They recycle important elements that are used by producers for healthy growth.

Decomposers carry out two important jobs in an ecosystem. What are they?

The compost contains recycled minerals that help plants to grow.

The compost releases nitrogen into the air for plants to use.

The compost makes new minerals that help plants to grow.

The compost helps to keep animals off the garden.

Compost is a product made when dead plant material decomposes. Why is compost useful for gardeners to add to their soil?

When bacteria and fungi break down organic matter in very dry soils.

When plants compete with decomposers for food.

When bacteria and fungi produce energy from food to carry out life processes.

When bacteria and fungi break down organic matter in waterlogged soils.

When does anaerobic decomposition take place?

Starter Quiz