Communities:

1. Communities: Group 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) energyvia the process of photosynthesis. EX: all plants, algae, photosynthetic bacteria

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.

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

9. Decomposition occurs at any level of the chain C,H,O,N Light energy Photosynthesis Chemical energy carbohydrates SUNGLASSES

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

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

12. 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.

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

14. Food Web Activity