Ecology

1. Ecology Energy Transfer and nutrient recycling WALT How nutrients are recycled through an ecosystem The carbon cycle

2. Autotrophs in an Ecosystem are producers, the products that they make form the food that ultimately feed all of the organisms in the ecosystem. • Primary consumers are herbivores and get their energy from feeding on the autotrophs • Secondary consumers feed off the primary consumers • Tertiary consumers prey on other meat eaters

3. Food chains are chains of dependence Each distinct level is called a trophic level Primary consumers Secondary consumers Tertiary consumers Producers As one organism eats another there is a transfer of energy through the trophic levels Energy transfer occurs in one direction only

4. All organisms need a supply of energy to carry out the processes of life • They also need to obtain mineral nutrients such as carbon and nitrogen in order to make up complex chemicals such as proteins. • Unlike energy mineral nutrients are recycled over and over again • Some people say that in our lives we will breathe out 6 carbon atoms that were once a part of Napoleon Bonaparte!!!

5. Producers accumulate mineral nutrients These then pass along the food chains Finally they are released back into the abiotic part of the ecosystem by decomposers

6. Mineral nutrients occur in four basic compartments in an ecosystem • The organic molecules in living and dead organisms • Organic matter held in the soil • Fossil fuels and sedimentary rocks • In the atmosphere • Dissolved CO2 and Calcium Carbonate in the sea

7. The Carbon Cycle • Carbon circulates between the abiotic and biotic parts of the ecosystem

8. Carbon Cycle • Fragments of decaying material is called detritus • Small animals known as detritivores feed on the detritus and so contribute to the decomposition process • Detritivores include earthworms, woodlice and slugs • Decomposers then complete the decomposition – bacteria and fungi

9. photosynthesis Carbon Dioxide in the atmosphere Carbon in organic molecules in plants Ingestion Digestion absorption respiration in plants death Carbon in organic molecules in animals Respiration in animals Egestion death Respiration of decomposers Carbon in dead organic matter fossilisation burning Carbon in fossil fuels

10. 92% of global CO2 production is from respiration (over which we have no control) and only 2% is produced by all forms of transport!

11. Atmospheric CO2 levels are rising steadily (see right), but there is no way that humanity can stop this rise and even more uncertainty as to the consequences of this rise. Plant growth will certainly increase, as lack of CO2 is the limiting factor for photosynthesis throughout the world (in summer, anyway).

12. The Carbon Cycle • Explain what is meant by a carbon source and a carbon sink • Explain how humans influence the carbon cycle