A group of organisms of the same type, in the same place, is called a population.

Sampling is a survey of plants and/or animals which provides information about the populations of organisms.

A quadrat is a square frame which is used to sample populations of plants or slow-moving animals.

Abundance is the number of organisms of a species found within a habitat.

Estimating population size using quadrats: practical

Combined science

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

Physical activity and equipment requiring safe use

how organisms interact with each other in the environment.

how many different organisms there are in a habitat. 

the number of one species that is found in a habitat.

how often a quadrat is used in an investigation. 

Quadrats should be placed randomly by throwing them. 

More reliable results are given by taking a large sample.

Quadrats should only be used in the summer when plants are flowering.

Quadrats are useful to sample populations of mice.

Which of the following is true about quadrats?

What is the area of a quadrat that measures 0.5 m × 0.5 m?

Look at the results from a quadrat survey of dandelion plants. Calculate the mean number of dandelion plants in each quadrat.

Ten 1 m² quadrats were placed in a 40 m² field. A mean of 2 snails were found in every quadrat. Estimate the population size of the whole field.

The results from a quadrat survey of dandelion plants in a school field is shown. Each quadrat is 1 m². If the school field is 1000 m², estimate the total population size of dandelion plants.

True or false? A bottle garden is an example of an ecosystem.

Which of the following populations of organisms might you use a quadrat to sample?

The diagram shows a pitfall trap. Which of the following organisms might be sampled using this piece of equipment?

Rainfall in a habitat is an example of ...

To make sure that the mark stands out so it is easy to count.

To use a substance that is harmless to the organism.

To make the organism stand out to a predator.

When carrying out a mark-release-recapture experiment we put a small mark on the organism so that we know it has been captured before. What is important to remember when marking an organism?

Content guidance

Risk assessment required - equipment

Adult supervision required

This lesson will be removed by end of Summer Term 2025.

Estimating population size using quadrats: practical

Lesson outcome

Content guidance

This lesson will be removed by end of Summer Term 2025.