1. Patterns of Interaction
Relationships between organisms in an ecosystem

2. Competition
Competition occurs when organisms compete for limited resources, such as food, water, light, or space.
Competition can occur between organisms of the same species (intraspecific) or organisms of different species (interspecific).
Examples: two trees compete for light within the forest (intraspecific); cheetahs and lions compete for similar prey (interspecific)

3. “Anemones Attack” Video clip-2:49

4. Predation
An organism, called a predator, feeds on another living organism, known as prey.
Predator-prey relationships are essential for healthy ecosystems.
Examples: a lion catches, kills, and eats a zebra; a praying mantis catches and eats a fly.

5. “Dragonfly Larva Hunts Newt”
Video clip-2:06

6. Mutualism
A symbiotic relationship in which both organisms benefit from the interaction.
Example: A clownfish provides protection from predators for the sea anemone, while the anemone's stinging tentacles protect the clownfish from predators.

7. Commensalism
A symbiotic relationship in which one species receives a benefit, while the other is unaffected.
Example: Cattle egrets live near livestock and eat the insects that are attracted to the animals, while the livestock is unaffected by the egrets.

8. Parasitism
A symbiotic relationship in which the parasitic species benefits, while the host species is harmed.
Example: A hookworm lives in the intestines and lungs of a host organism and causes them pain.

9. “Symbiosis: Mutualism, Commensalism, and Parasitism”
Video clip-5:17

10. Bibliography
Harwood, J., & Wilkin, D., Ph.D. (n.d.). Competition. Retrieved December 17, 2016, from
Harwood, J., & Wilkin, D., Ph.D. (n.d.). Predation. Retrieved December 17, 2016, from
Harwood, J., & Wilkin, D., Ph.D. (n.d.). Symbiosis . Retrieved December 17, 2016, from