1. Community Ecology

2. Community
group of populations interacting with one another within the same environment.
Example: fallen log with all species that live within it.
Species diversity increases the closer you get to the equator.
Composition of a community – list of species
Diversity of a community – includes number of species and their abundance

3. Competition
Interspecific competition – members of different species try to use a resource that is limited.
May result in resource partitioning leading to niche specialization.
Competitive exclusion principle – no two species can indefinitely occupy the same niche at the same time

4. Structure of the community
Habitat – place where an organism lives and reproduces
Ecological niche – role it plays in its community, including habitat and interactions with organisms
Fundamental niche – all conditions under which the organism can potentially survive and reproduce
Realized niche – set of conditions under which it exists in nature.
Competition forces an organism to occupy its realized niche, which is smaller than fundamental

5. Predator-prey Predation – when a predator feeds on prey Prey defenses
In nature, the presence of predators can decrease prey densities and vice versa
Prey defenses
Camouflage – ability to blend into a background
Walking sticks, katydids
Mimicry – when a species resembles another that possesses an antipredator defense
Batesian – mimic that lacks the defense
Mullerian – mimics that share the same protective defense

6. Cryptic coloration and aposematic coloration

7. Mullerian mimicry and Batesian mimicry

8. Symbiotic relationships
3 types: parasitism, commensalism and mutualism
Parasitism: parasite derives nourishment from another, a host. Parasites can weaken or kill host, +, -
Commensalism – between two species in which one species is benefited and the other is neither benefited nor harmed, +, 0
Mutualism – both members of association benefit, +,+ Mycorrhizae

9. Parasitism, Mutualism

10. Commensalism

11. Community Development
Ecological succession – change involving a series of species replacements in a community following a disturbance.
End result can not be predicted
Pioneer species – first species to begin secondary succession

12. Ecological Succession

13. Community Biodiversity
Intermediate disturbance hypothesis – moderate amounts of disturbances at moderate frequency are required for a high degree of community diversity. Ex. Fire
Keystone species – organisms that play a great role in maintaining the function and diversity of an ecosystem than would be predicted by their abundance.

14. Keystone species