Organism and Ecosystems

Ecosystems

​What is an ecosystem?

It is a system of organisms interacting with each other and with a physical environment. It can be small e.g. a pond, or large e.g. a forest.

The Components of Ecosystems

Ecosystems usually have the same components:

Producers

Consumers

Decomposers

The Physical Environment

Producers are plants that photosynthesise to produce food.

Definition

What is a producer?

​THINK: P FOR PRODUCER
P FOR PLANT

Multiple Choice

Which of these is a producer?

• Rabbit

• Grass

• Horse

• Eagle

Consumers are animals that eat other plants or animals.

Definition

What is a consumer?

An organism that breaks down dead material and helps to recycle nutrients.

Definition

What is a decomposer?

An organism that breaks down dead material and helps to recycle nutrients.

Definition

What is a decomposer?

​The components of ecosystems

The living components of an ecosystem are called the biotic components. The non-living (physical) components are the abiotic components.

E.g Biotic - tadpole, plankton
Abiotic - water, soil

​Habitat

The place where an organism lives.

For example, habitats in a pond ecosystem include the open water, the mud at the bottom of the pond, and the surface water.

​Population

All of the organisms of a particular species found in an ecosystem form the population.

For example, all of the tadpoles swimming in a pond are the population of tadpoles.

​Community

The populations of all species (animals, plants and other organisms) found in an ecosystem form the community.

​Biodiversity

The amount of variation shown by organisms in an ecosystem.

Biodiversity is a measure of both numbers of species and abundance of each species.

​Quadrats

These are used to estimate how many organisms there are in a particular habitat.

They are used to count things that don't move a lot e.g. plants or snails.

These are physical or chemical factors.

​Abiotic

These are biological factors.

​Biotic

There are many factors that affect the numbers and distribution of organisms in an ecosystem. There are two types of factor - biotic and abiotic.

​Biotic Factors

​Predation

​Presence of pollinating insects

​Parasitism

​Availability of nest sites

​Availability of food

​Competition for food resources

​Disease

​Abiotic Factors

​Pollution

​Soil conditions

​Hours of daylight

​pH of soil or water

​Light intensity

​Temperature

​Water availability

Open Ended

Discuss some of the biotic and abiotic factors that may affect animals that live in a river.