1. Energy Flow in an Ecosystem

2. Biomass  The total mass of living plants, animals, fungi and bacteria in a given area

3.  Organisms have special roles, or niches, in the ecosystem in which they live.  Within its niche, every organism interacts with that ecosystem in two ways: 1. The organism obtains food energy from the ecosystem 2. The organism contributes energy to the ecosystem

4. Food Webs Herbivores – eats plants Carnivores – eats animals Omnivores – eats plant and animals Insectivore – eats insects Top predator Consumers: all animals + fungi + some bacteria Producers: all plants + some bacteria

5. What happens when organisms die? When organisms die, they become detrius  DETRIUS is all the dead plants, dead animals, and animal waste  Detrius – contains organic (carbon containing) and inorganic compounds

6. Detrivores  Detrivores – organisms like snails, beetles, and earthworms that EAT detrius.  This helps decomposition because it increases the surface area of detrius

7. Decomposers  Decomposers – organisms like Bacteria and Fungi break detrius into smaller molecules (nutrients) that can be absorbed by other organisms  Nutrients are recycled back into ecosystem

8. Biodegradation  Biodegradation – if something is biodegradable then it can be decomposed by Bacteria and Fungi  Example: many plastics are non-biodegradable (cannot be broken down by decomposers)

9. Detrivores and Decomposers occur at all levels of the food web

10. Food Chains  A food chain shows the flow of energy from producers to consumers  Trophic level (aka: feeding level) is the position the organism occupies in the food chain  Each trophic level helps ID the organism’s niche or role in the ecosystem

11. Trophic Levels Term  Primary Producer  Primary Consumer  Secondary Consumer  Tertiary Consumer Example  Plants  Herbi or omnivores  Omni or carnivores

12. Energy Flow  Plants use energy to produce carbohydrates (+ other organic molecules) in a process called photosynthesis

13. Energy Flow  These carbohydrates (sugars) are used as energy by plants as well as consumers that eat plants

14. Energy Flow  All consumers store excess energy as glycogen (carbohydrate), fat, and protein  Omnivores and carnivores can get their energy by eating other consumers (animals)

15. Energy Flow  Most organisms on the Earth get their energy either directly or indirectly from the sun

16. Ecological Pyramids

17.  Pyramid of energy – the 90%/10% rule  Only 10% of the available energy is transferred from one trophic level to the next  90% of the energy an organism takes in is used for growth and repair or lost as heat

18. Ecological Pyramids  90%/10% rule is why many food chains have a maximum of 5 trophic level

19. Spent on Food PLANTS Spent on Food CRICKETS SNAKES EAGLES

20. Pyramid of Biomass and Numbers

21.  As you move up the food chain there are fewer organisms.  Because energy is lost at each trophic level  Less energy available at each level means that fewer individuals can be supported

22. Pyramid of Biomass and Numbers  As you move up the food chain there is less biomass  Total mass of all organisms at the trophic level drops the higher up the food chain you go