1. ENERGY FLOW: Where does the Energy Go? (fig 34.2, 34.3)

2. Laws of Thermodynamics… 1. Energy is neither created or destroyed, only transferred 2. With every transfer, some energy is lost to HEAT (or other less available form of energy)

3. BIOTIC COMPONENTS of an ECOSYSTEM PRODUCERS (produce food) Chemoautotrophs- bacteria that use inorganic chemicals like ammonia, nitrites, sulfides to make food) Photoautotrophs-use energy from the sun…produce most of the organic nutrients for the biosphere CONSUMERS (consume food) Need a preformed souce of organic nutrients Consumers can be : Primary/Secondary/ Tertiary (See next) DECOMPOSERS (Break down dead organic matter) VALUABLE- release inorganic nutrients for plants to take up Ex- nonphotosynthetic bacteria, fungi DETRITUS= partially decomposed matter in the water or soil What does each arrow represent?

5. Kinds of Consumers Scavengers Primary/1 st level Secondary/ 2 nd level Tertiary/ 3 rd level

6. Herbivore : Feed on grass and other plants  Primary Consumers Carnivore : Eat animals Carnivores that eat Herbivores  Secondary Consumers Carnivores that eat other carnivores  Tertiary Consumers Omnivore : Eat both plants and animals.

7. FOOD CHAINS… Food Chains show how matter and energy move through an ecosystem

8. A weakness in the chain… Food chains can only have up to about 5 links … Why? because the animals at the end of the chain would not get enough nutrients and energy. So…most animals are part of more than one food chain in order to meet their requirements… This creates…

9. FOOD WEBS Interconnected food chains. They express all the possible feeding relationships at each trophic level in a community. IMPORTANT POINT: Arrows are drawn from food source to consumers (substitute “eaten by” for arrows)

10. All food is NOT created equal… TROPHIC LEVELS: All the organisms that feed at a particular link in a food chain 10% rule: In general only about 10% of the energy from one trophic level is available to the next!!!

11. Biomass Pyramid The total amount of living material present in each trophic level (a feeding step in a food chain). NOTE: are there more autotrophs or heterotrophs? WHY?

12. Pyramid of Numbers Each bar in the pyramid represents the size of the populatoin at that trophic level

13. Pyramids of Energy Each bar in the pyramid represents the energy available within that trophic level