1. Environmental Biology & Genetics Energy Flow M r G D a v i d s o n

2. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20152Mr G Davidson Ecosystems  An ecosystem is a natural unit composed of living organisms and their non-living environment, e.g. a woodland.  A habitat is the place where an organism lives, e.g. greenfly live on the leaves of the trees.  An organism’s niche is the role it plays within the ecosystem e.g a tawny owl is top predator in a woodland.

3. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20153Mr G Davidson Ecosystems

4. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20154Mr G Davidson Ecosystems  A population is the total number of organisms of one species living in a habitat, e.g. the total number of greenfly in the woodland.  A community is made up of all the living organisms in a habitat, e.g. all the trees, grass, insects, birds, etc..

5. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20155Mr G Davidson Ecosystems

6. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20156Mr G Davidson Ecosystems  A species is a group of organisms which can interbreed to produce fertile offspring. DonkeyHorse Mule Horses and donkeys can mate to produce a mule – but mules are not fertile so horses and donkeys are separate species

7. Ecosystems  All of the energy required by all living organisms in an ecosystem comes from the sun.  Light energy from the sun is converted to chemical energy by plants in a process called photosynthesis. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20157Mr G Davidson

8. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20158Mr G Davidson Producers & Consumers  Producers are organisms which can produce their own food by photosynthesis – usually green plants.  Consumers are animals which consume (eat) other organisms. They cannot make their own food.

9. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 20159Mr G Davidson Producers & Consumers  A primary consumer is an animal which eats plants, and is also known as a herbivore.  A secondary consumer is an animal which eats primary consumers, and is also known as a carnivore.

10. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201510Mr G Davidson Producers & Consumers  An omnivore can eat both plants and animals.  Decomposers are bacteria and fungi which break down dead plants and animals for energy and release their nutrients back into the ecosystem.

11. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201511Mr G Davidson Producers & Consumers  An animal which hunts other animals for food is called a predator.  An animal which is hunted by other animals as food is called prey.

12. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201512Mr G Davidson Food Chains & Webs  A FOOD CHAIN shows a feeding relationship. It is usually written as: Green plantherbivorecarnivore  The arrows in a food chain point from food to feeder and show the direction of energy flow.  A food chain always starts with a producer (green plant).

13. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201513Mr G Davidson Food Chains & Webs  Energy is transferred in the form of chemical energy in food from plants to animals and then to other animals.  A green plant (producer) can be eaten by a herbivore.  The herbivore in turn can be eaten by a carnivore.

14. Food Chains and Food Webs Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201514Mr G Davidson Green Plant PRODUCER Rabbit PRIMARY CONSUMER (HERBIVORE) Fox SECONDARY CONSUMER (CARNIVORE) ENERGY

15. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201515Mr G Davidson Food Chains & Webs  Feeding relationships are more complicated than food chains suggest.  Food chains interconnect at many points.  This interconnection of food chains is called a food web.

16. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201516Mr G Davidson Food Chains & Webs FOX SNAIL HEDGEHOG WEASEL FROG VOLE PRIMROSE PLANT OWL RABBIT OAK

17. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201517Mr G Davidson Energy Flow and Loss  Every time one organism eats another, energy is transferred from the food to the feeder.  The arrow indicates the direction of energy flow.  E.g. Oak leafCaterpillarShrewBadger

18. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201518Mr G Davidson Energy Flow and Loss  Not all the energy available at each step in a food chain is passed onto the next step.  Only about 10% is passed on.  90% of the energy is lost e.g. as:  Movement  Heat production  Waste.

19. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201519Mr G Davidson Pyramid of Numbers  A pyramid of numbers is a diagram which represents the number of organisms at each stage in a food chain.  A pyramid of numbers can look like:

20. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201520Mr G Davidson Pyramid of Numbers Grass Greenfly Ladybird Thrush Number of organisms decrease Size of organisms increase

21. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201521Mr G Davidson Pyramid of Numbers Grass Greenfly Ladybird Thrush

22. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201522Mr G Davidson Pyramids of Energy  A pyramid of energy is a diagram which represents the amount of energy available at each level of a food chain.  It is usually measured in kilojoules of dry mass per square metre per year.

23. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201523Mr G Davidson Pyramid of Energy 100 000 kJ 10 000 kJ 1 000 kJ 100 kJ

24. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201524Mr G Davidson Pyramid of Biomass  A pyramid of Biomass is a diagram which represents the total mass of organisms at each level of a food chain.

25. Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 201525Mr G Davidson Pyramid of Biomass Oak leaves Caterpillars Sparrows The energy available to the caterpillars is less than the energy available to the sparrows, and therefore, the caterpillars produce a greater biomass than the sparrows.

26. Vocabulary ecosystemcarnivore habitatpredator nicheprey populationdecomposer communityspecies producerpyramid of numbers primary consumerpyramid of biomass secondary consumerpyramid of energy herbivore Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015Saturday, April 18, 2015 26Mr G Davidson