1. Community Ecology Chapter 20
Biology 138

2. Species Interactions Five major types of interactions or symbioses.
1. Predation
2. Parasitism
3. Competition
4. Mutualism
5. Commensalism

3. Predation Predators vs. Prey -Regulates population size.
-Adaptations lead to natural selection.
-Survival…carry on the species!
Defense Mechanisms:
Mimicry
Camouflage
Physical Defenses
Secondary Compounds (Poisonous)

4. Which snake is poisonous?
The nonvenomous Sinaloan milk snake (right), for example, closely mimics the color pattern of the venomous coral snake.

5. Polyohemus Moth mimics an owl.

7. Competition
Principle of Competitive Exclusion --- Local extinction of a species due to competition
Character Displacement --- Evolution of differences between body parts which reduces competition between similar species
Resource Partitioning --- Competition is intense between closely related species because they require the same resources. So when they coexist, each species only uses part of the available resources.

8. Last Types of Symbiosis
Mutualism:
Both species benefit.
Commensalism:
One species benefits, the other is not affected.
Parasitism:
Parasite vs. Host
Ectoparasites vs. Endoparasites