Biodiversity and the distribution of life on planet earth

Re-cap - Ecosystems

An ecosystem is a community of , animals and smaller organisms that live, , reproduce and interact in the same habitat or environment.The non-living components include ,pH, , CO2 , O2 and other chemicals.

An ecosystem consists of all the living in a particular and the components with which the organisms interact

plants, temperature, habitat, light, feed, non-living, organisms,

Today we are learning about Niches

The interactions include other organisms in the community including competition, parasitism and predation.

A niche includes the use organisms make of the resources in their ecosystem, including light, temperature and nutrient availability.

A niche is the role that an organism plays within a community.

All organisms in an ecosystem have a particular niche.

Plants are the producers.This means they can photosynthesise and make their own food.

What is the role of plants in an ecosystem?

There are exceptions to this and some plants supplement the poor nutrient levels in their ecosystem by digesting insects.Can you name any plants that do this?

Animals have a variety of niches in an ecosystem oftenassociated with their feeding level.These levels are primary consumer, secondary consumer,tertiary consumer, etc..

Primary consumers are animals that feed directly on the plants and would be called herbivoresSecondary consumers are animals that feed on the primary consumers.Tertiary consumers are animals that feed on the secondary consumers.

Organisms are often grouped in a niche in relation towhere they get their energy (food).This includes herbivores, carnivores, omnivores and decomposers.Do you know the difference?Herbivores eat plants to get their energy.

Omnivores eat both plants and animals to get their energy.

Carnivores eat other animals to get their energy.

Decomposers use waste and dead material to get their energy.

The feeding relationships in an ecosystem can be represented by drawing food chains and food webs.

A food chain could look like thisGrass Rabbit Fox

The arrows represent the flow of energybetween the different organisms.

Food webs are just many food chains from anecosystem linked together.They show how complex and interlinked the relationshipsare between organisms in an ecosystem.

A typical ocean food web Pick out some foodchains from this food web

Using the Scottish Highlands you will now construct somefood chains and a food web.

Each group or pair needs the organisms cards,the organisms feeding information and a piece of A1 paper.• Read the organism feeding information sheet.• Use the cards to construct a food chain. (There are arrows provided)• Use as many cards as possible to construct a food web.(The organisms cards should be put on the A3 paper and the arrows drawn in with a marker)

Organisms in an ecosystem are influenced by theirrelationships with each other.

If organisms require the same or similar resourcesthen they will need to ‘fight’ for them.This is called competition.

Relationships between organisms

Plants will often compete for light, space and available nutrients.

As a result of competition between two organisms theirsuccess in the ecosystem will be affected.

Animals will often compete for food, space and reproductive mates.

Sometimes organisms live in relationships that areParasitic.

Parasites are organisms that live on or in another organism.

Relationships between organisms

One of the organisms will benefit from the relationshipwhilst the second organism will be harmed.Examples of this include ticks and tapeworms

Another relationship that will affect how successfulorganisms are is that between predators and their prey.

Predators get their food by eating other animals.

Relationships between organisms

The numbers of predators will affect the numbers oftheir prey (the animal being eaten).

Take a look at the graph and think about how the predators and prey affect each other

Examples of predators include pine marten, eagles,wolves and bears.

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=XgaBFeddcJRJ2M&tbnid=y9Sn5UpdEec2iM:&ved=0CAUQjRw&url=http://people.whitman.edu/~hundledr/courses/M250F03/M250.html&ei=AFmgUtfoDuO70QXukoG4CA&bvm=bv.57155469,d.ZGU&psig=AFQjCNHD6MqfJVI7kT4M_5zZZNw-y8zosA&ust=1386326547105533

What did you notice?

• As the prey numbers increase the predator numbers increase.

• As the predator numbers increase the prey numbers decrease.

Can you explain this?

• As the prey numbers decrease the predator numbers decrease.

Could there be other factors affecting the populations?

InvestigationYou are going to Plan, Carry out and Write up an investigation into competition between cress seedsfor space to germinate

• The teacher will introduce and discuss the investigationwith the class.

• A help sheet for the investigation write up will be given to you

• The investigation will then be carried out and written up.

• There will be an initial planning phase that must be completed before carrying out the investigation.

We have been learning about Niches

Competition, parasitism and predation.

Light, temperature and nutrient availability.

A niche is the role that an organism plays within a community.

What is a niche?

What kind of resources will organisms be using in theirecosystem?

What types of interactions occur between organisms inA community?