1. Energy in Ecosystems

2. The Flow of Energy The energy in ecosystems does not flow in cycles like matter does -such as nitrogen, water, carbon - but flows in a straight line. If energy is not passed on it is lost (such as heat). This means that there must be a constant supply of energy to sustain the ecosystem.

3. The Flow of Energy HerbivoreOmnivore Carnivore H2OH2O O2O2 CO 2 C 6 H 12 O 6 Photosynthesis in the chloroplast converts light energy into chemical energy: 6CO 2 + 6H 2 O 6O 2 + C 6 H 12 O 6 90% lost 20% lost 20% of energy lost 10% lost 90% of energy is lost Energy lost through cellular Respiration + Heat Cellular respiration takes place in the mitochondria of all cells and is responsible for releasing the energy stored in glucose to make ATP which breaks down to ADP 6O 2 + C 6 H 12 O 6 6CO 2 + 6H 2 O + Energy Detritus: energy lost as waste products and ‘dead’ material Decomposers such as bacteria and fungi recycle nutrients such as nitrogen and carbon

4. Photosynthesis & Respiration These two complex reactions appear to be the reverse of each other, but in actual fact they are not. The plants convert the light energy into chemical energy, which is stored in organic compounds such as glucose. The glucose is passed from the plants to the animals when they eat them, and then on to other animals the same way. The breakdown of glucose releases energy into the organism which releases energy into the ecosystem.

5. Respiration All living cells need a constant supply of energy all the time to stay alive. They need this energy to synthesize new molecules, to grow, to reproduce, to repair and maintain themselves, to transport various materials and to undergo various generalised and specialised functions. Respiration itself is a series of about 50 different chemical reactions, each one using a different enzyme to catalyse it. The chemical energy held in the bonds of glucose release energy when they are broken. This energy is transferred to ATP (adenosine tri phosphate) where is can then be used by the cell. About 40% of the energy in glucose is converted to ATP.

6. Respiration This is an over simplified diagram of how the reactants and products in respiration balance each other out.

7. Respiration glucose + oxygen carbon dioxide + water + energy ADP + P +glucose +oxygen carbon dioxide + water + ATP ADP + PATP Energy out Energy in

8. Respiration The stages of respiration can be thought of as occurring in two stages. The first stage occurs in the cytoplasm, produces 2 ATP’s and does not require oxygen. This is known as glycolysis or anaerobic respiration. The second stage occurs in the mitochondria of the cell, produces 36 ATP’s and is called aerobic respiration. When I undergo anaerobic respiration I produce lactic acid When I undergo anaerobic respiration I produce alcohol Sugar Lactic acid + carbon dioxide + 2ATP Sugar Ethanol + carbon dioxide + 2ATP

9. Photosynthesis & Respiration The role of Photosynthesis in the ecosystem: To provide oxygen for all living things in order to undergo respiration To provide food for herbivorous animals in the form of glucose To trap the sunlight energy so that it can actually enter the ecosystem The role of Respiration in the ecosystem: To provide carbon dioxide for plants to use during photosynthesis To release the energy in glucose so it can be used in the ecosystem

10. Food Chains A food chain represents the flow of energy from one living thing to another Producer 1 o Consumer Herbivore 2 o Consumer 1 o Carnivore 3 o Consumer 2 o Carnivore..or if we want to look at trophic levels….. 1 st trophic level 2 nd trophic level 3 rd trophic level 4 th trophic level

11. Food Webs A food web is a set of food chains interacting 1st trophic level 2nd trophic level 3rd trophic level 4th trophic level Producer Primary consumer Secondary consumer Tertiary consumer Top order consumer

12. Pyramids of Energy Producers Primary consumers Secondary consumers Tertiary consumers Each step represents the amount of energy available. At each tropic level the amount of energy is reduced. Greater tropic efficiency gives a pyramid with much steeper sides compared to a food chain with poor tropic efficiency.

13. Pyramids of Numbers Pyramids of numbers are essentially population pyramids. They need not always take the step progression of energy pyramids. So often they don’t even appear pyramidal in shape. Here are a few examples: Plants Kangaroos Parasites Producers

14. Biomass Pyramids The total amount of mass in a community, or a given tropic level is called the biomass. They are time consuming to make and are nearly always pyramidal. Producers

15. The End!