3/28/13

I.
     B. Predation
          2.
               d. Keystone Predator
                    ii. Maintain Species Diversity- preys on the most commonly occurring species leaving more resources for the less commonly occurring species.
     C. Symbiosis- "living together". At least one species in the relationship has a lifelong dependance on the other. Three types:
          1. Parasitism (+/-)- When one species (parasites) lives off of and on or in another (host).
          2. Mutualism (+/+)- both species benefit.
               a. Flowering Plants and Pollinators- 70% of plants flower.

               b. Lichen- an alga and a fungus. Fungus excretes digestive enzymes break down substrate to get nutrients (N, P, S, Na+, K+, etc) and alga photosynthesizes to make sugars and fats. First step in soil formation.

               c. Commensalism- (+/0)- one species benefits and the other is unaffected. Epiphytes- plants that live on other plants- Orchids