Biodiversity and the distribution o f life on planet earth

1. Biodiversity and the distribution of life on planet earth

2. Re-cap - Ecosystems An ecosystem consists of all the living in a particular and the components with which the organisms interact • 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. plants, temperature, habitat, light, feed, non-living, organisms,

3. Today we are learning about Niches A niche is the role that an organism plays within a community. A niche includes the use organisms make of the resources in their ecosystem, including light, temperature and nutrient availability. The interactions include other organisms in the community including competition, parasitism and predation.

4. All organisms in an ecosystem have a particular niche. What is the role of plants in an ecosystem? Plants are the producers. This means they can photosynthesise and make their own food. • 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?

5. Animals have a variety of niches in an ecosystem often associated 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 herbivores Secondary consumers are animals that feed on the primary consumers. Tertiary consumers are animals that feed on the secondary consumers.

6. Organisms are often grouped in a niche in relation to where they get their energy (food). This includes herbivores, carnivores, omnivores and decomposers. Do you know the difference? Herbivores eat plants to get their energy. • Carnivores eat other animals to get their energy. • Omnivores eat both plants and animals to • get their energy. Decomposers use waste and dead material to get their energy.

7. The feeding relationships in an ecosystem can be represented by drawing food chains and food webs. A food chain could look like this Grass Rabbit Fox The arrows represent the flow of energy between the different organisms. Food webs are just many food chains from an ecosystem linked together. They show how complex and interlinked the relationships are between organisms in an ecosystem.

8. A typical ocean food web Pick out some food chains from this food web

9. Using the Scottish Highlands you will now construct some • food 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)

10. Relationships between organisms Organisms in an ecosystem are influenced by their relationships with each other. If organisms require the same or similar resources then they will need to ‘fight’ for them. This is called competition. • Plants will often compete for light, space and available • nutrients. • Animals will often compete for food, space and • reproductive mates. • As a result of competition between two organisms their • success in the ecosystem will be affected.

11. Relationships between organisms Sometimes organisms live in relationships that are Parasitic. Parasites are organisms that live on or in another organism. • One of the organisms will benefit from the relationship • whilst the second organism will be harmed. • Examples of this include ticks and tapeworms

12. Relationships between organisms Another relationship that will affect how successful organisms are is that between predators and their prey. Predators get their food by eating other animals. • The numbers of predators will affect the numbers of • their prey (the animal being eaten). • Examples of predators include pine marten, eagles, • wolves and bears. • Take a look at the graph and think about how the • predators and prey affect each other

14. What did you notice? • As the prey numbers increase the predator numbers increase. • As the predator numbers increase the prey numbers decrease. • As the prey numbers decrease the predator numbers decrease. Can you explain this? Could there be other factors affecting the populations?

15. Investigation You are going to Plan, Carry out and Write up an investigation into competition between cress seeds for space to germinate • The teacher will introduce and discuss the investigation • with the class. • There will be an initial planning phase that must be • completed before carrying out the investigation. • The investigation will then be carried out and written up. • A help sheet for the investigation write up will be given • to you

16. We have been learning about Niches What is a niche? A niche is the role that an organism plays within a community. What kind of resources will organisms be using in their ecosystem? Light, temperature and nutrient availability. What types of interactions occur between organisms in A community? Competition, parasitism and predation.