2. Ecosystem Interactions

3. Interactions The organisms in a community are capable of interacting with each other in some very complex ways. – They can: Hurt Each other Help each other Live indifferently

4. Competition Competition occurs when 2 or more organisms (same or different species) attempt to us the same resource at the same time and place. Resource: any necessity of life – Ex. Water, nutrients, light, food, space, etc… Two types: – Intraspecific: members of the same species compete for a resource – Interspecific: members of different species compete

5. Intraspecific Competition

6. Interspecific Competition

7. Predation An interaction in which one organism captures and feeds on another Predator- organism that does the killing and eating Prey- organism that is the food This relationship can have a drastic effect on the community (more on this later)

8. Symbiosis The relationship in which there is a close and permanent association between organisms of different species Three kinds of symbiosis are: – Mutualism – Commensalism – parasitism.

9. commensalism predation Symbiosis mutualism +/0 +/+ +/- -/

10. mutualism Relationship in which both species benefit from the interaction e.g., intestinal bacteria, lichens, pollinators

11. commensalism Relationship in which two organisms live together …one benefits and the other is unaffected e.g., barnacles on whales, orchids

12. parasitism a member of one species derives benefit at the expense of another species: usually harm but don’t kill host Parasite- organim that obtains benefit Host- organism that the parasite feeds from – e.g., ticks, mistletoe, disease-causing bacteria