Starter Activity: on a show me board What do plants and animals compete for? Plants Animals.

Starter Activity: on a show me board

What do plants and animals compete What do plants and animals compete for?for?

Plants Animals

Competition in Ecosystems

Learning Intention: Investigate interspecfic and intraspecific competition in ecosystems.

Success Criteria: Define interspecific competition and give examples.Define intraspecific competition and give examples.

What is competition?All living things need natural resources, but the problem is that there is not enough for everyone. This means that individuals have to fight for them in order to survive.

This struggle for resources is called competition.

Competition for resources between members of different species is called interspecific competition.

Who competes?

Competition for resources between members of the same species is called intraspecific competition.

Differerent species = Intererspecific Saame species = Intraaspecific

There are four resources for which animals compete. What are they?

What do animals compete for?

food

mates

water

land (territory)

Which resource is not relevant for interspecific competition? Members of different species will not compete for mates.

Competition between plants may be less noticeable than competition between animals but it still takes place. What four things do plants compete for?

What do plants compete for?

light

minerals

water

space

Competition results in winners and losers.

move to an area where there is less competition.

How can a less competitive species avoid extinction? adopt new survival strategies

Competition and Evolution

Winners obviously benefit from gaining resources, but what happens to the losers?

This means that competition is driving force behind natural selection and evolution. Individuals with genes that make them more competitive are more likely to survive and pass on those genes.

Individuals and species that are less competitive are at risk of dying out because they will struggle to gain resources.

less competiti

on

population rises

Competition and population sizeThe size of a population varies due to factors such as

disease, migration and predation.

Intraspecific competition generally has a stabilising effect on a population. Why is this?

population falls

more competiti

on

Decline of the red squirrelThe red squirrel is a native species of the British Isles, living in coniferous and broadleaf woodlands.

Red squirrels were once widespread throughout the British Isles but in the last 50-60 years, their numbers have dramatically declined and they are now absent from many areas.Small, isolated populations exist on the Isle of Wight, Wales and central England. They are still widespread in the North of England and Scotland.

What has caused the decline of the red squirrel?

Why have red squirrels declined?

The destruction of red squirrels’ natural habitat has contributed to their decline but the major reason is because of competition from the grey squirrel.

The grey squirrel is not native to the British Isles but was introduced from North America towards the end of the 20th century. It is larger and more aggressive than the red squirrel.

It is not clear exactly how grey squirrels have caused the decline of red squirrels but scientists think that greys are more successful in foraging for food than reds.

Investigating Competition in Plants

• 3g of cotton wool was placed in two yoghurt pots wrapped in black paper, along with 30ml of water.

• 1g of mustard seeds were planted in pot 1.

• 10g of mustard seeds were planted in pot 2.

• The pots were placed on a warm window ledge for 5 days.

• After 5 days the seedlings were removed from the pots and were dried out in an oven until a constant dry mass was obtained.

An investigation into intraspecific competition in mustard seedlings was carried out:

Your tasks…Your tasks…

1. Draw a labelled diagram to show the contents of the pots competing for.

2. Explain why the pots were left for 5 days.

3. Name the pot where intraspecific competition was the greatest.

4. when they were set up, naming the independent, dependent and constant variables.

5. Name two resources that the seedlings could be Suggest why the seedlings were dried until a constant mass was reached.

A summary of competition

Answers on a show me board

Competition in Ecosystems

Learning Intention: Investigate interspecfic and intraspecific competition in ecosystems.

Success Criteria: Define interspecific competition and give examples.Define intraspecific competition and give examples.