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:
The organism obtains food energy from the ecosystem
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
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. Ferns  Crickets  Snakes  Eagles
Trophic Levels
Term
Primary Producer
Primary Consumer
Secondary Consumer
Tertiary Consumer
Example
Plants
Herbi or omnivores
Omni or carnivores
Ferns  Crickets  Snakes  Eagles

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. Ecological Pyramids 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 Spent on Food Spent on Food Spent on Food Owner Editors
Reporters
Spent on Food
Mailroom
Spent on Food

20. Ecological Pyramids - Example
Wolf eats a deer but does not consume all deer parts + some of the food eaten is eliminated as waste
Therefore, the wolf only gets a portion of the available energy from the deer
The energy the wolf does get is used to keep the wolf alive, to maintain its body temperature, and some energy is lost as heat

21. Pyramid of Biomass and Numbers

22. Pyramid of Biomass and Numbers
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

23. 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