1. Communities:
Groups of populations interacting within the same habitat.
Usually as feeding relationshipsflow of energy.

2. Communities
Within a community, species are identified based on their role within a community: niche
3 Major Niches
Producers
Consumers
Decomposers

3. Producers:
All autotrophs. These convert unusable energy(solar) into usable
(chemical) energy via the process of photosynthesis.
EX: all plants, algae, photosynthetic bacteria
Note: chemosynthetic bacteria are producers for the communities where no sunlight penetrates around volcanic vents deep in the ocean

4. Consumers
Consume energy by “eating/absorbing” other producers and consumers.
All Heterotrophs are consumers
Niches: Herbivores, Omnivores, Carnivores, Scavengers, Parasites, to name a few

5. Decomposers AKA: Detrivores Return organic matter to environment.
Major decomposers are the bacteria and fungi
However, some insects and organisms like earthworms can be considered decomposers

6. Relationships in Communities
Food Chains: single feeding relationship.

7. Decomposition occurs at any level of the chain C,H,O,N,P Light energy
Grass (Producer)
Mouse (Primary Consumer)
Fox (Secondary Consumer)
Mountain Lion (Tertiary Consumer) Apex Carnivore
Decomposition
occurs at any
level of the chain
C,H,O,N,P
Light energy
Photosynthesis
Chemical energy
carbohydrates
GREEN
HORNET

8. Food Chains All food chains must begin with producers.
Arrows  represent flow of energy.
Trophic levels identify consumers.
Generally primary consumers are herbivores.
Depending upon the food chain, some organisms can occupy different trophic levels.
Detrivores can occupy all trophic levels

9. Food Webs Complex feeding relationships. Illustrates many food chains
Mt. Lion
Complex feeding relationships.
Illustrates many food chains
Hawk
Fox
Snake
Goose
Deer
Grasshopper
MOUSE
Grass
Moss

10. Which organism seems to be the most important to this food web?
HAGH
Which organism seems to be the most important to this food web?

11. Keystone Species
Plays a critical role in maintaining the overall balance in an ecological community.
Stability of the community
depends upon species.
Keystone can occupy any
level or niche.

12. Which organism seems to be the most important to this food web?
Krill!

13. Food Web Activity

14. Food Web Activity

15. Grass (Producer)
Mouse (Primary Consumer)
Fox (Secondary Consumer)
Mountain Lion (Tertiary Consumer)