Communities

2. Communities Understanding how populations of organisms interact in communities. Mr. Roes Living Environment

3. Community Interactions • One of the foundational understandings of ecology as a whole is that organisms in a community are all interacting with each other constantly in one way or another. • Community interactions such as competition, predation, and various forms of symbiosis, can powerfully affect an ecosystem.

4. Community interactions • Every organism has a role that it fulfills—each organism has a way in which they get the resources that they need in order to survive. This is the idea of a niche. • The niche of an organism involves all of the physical and biological conditions that the organism lives in, and the way in which it uses those conditions.

5. Competition • In nature, ecosystems often can be limited in the amount of a resource that is available. • If two organism in the same community attempt to use the same resource, competition occurs.

6. Competition: • In nature, there is often a clear winner and loser in cases of direct competition. The loser will fail to survive if it remains in the same niche. • In ecology, we have a basic knowledge which states that no two organism can occupy the same niche in the same habitat at the same time. This is called competitive exclusion.

7. Predation • An entire food web is filled with many examples of predator-prey relationships. In an ecosystem, an organism could be a predator on an organism in a lower trophic level, while being the prey of an organism in the next highest food level. • Prey • Predator

8. Symbiosis • Sometimes in a community, there are examples of organisms of two different species living in an intentional relationship with each other. We call this a symbiotic relationship. • Symbiotic relationships can be categorized into three different groups; • Mutualism • Commensalism • Parasitism

9. Mutualism: • A relationship in which both organisms are benefitted. • Insects move from flower to flower, gathering their nectar, which the use as an energy source. The flowers benefit from the insects by being pollinated. • Nitrogen-fixing bacteria and leguminous plants.

10. Commensalism: • A relationship in which one organism is benefitted, and the second organism isn’t affected.

11. Parasitism: • A relationship in which one organism is benefitted, and the second organism is harmed

12. Draw this chart:

13. What form of symbiosis?

14. What form of symbiosis?

15. What form of symbiosis?

16. What form of symbiosis?