1. Ecology Interactions

2. Types of ecological interactions
competition
predation
parasitism
mutualism
commensalism
symbiosis

4. Competition – two species share a requirement for a
limited resource  reduces fitness of one or both species

5. Predation – one species feeds on another  enhances
fitness of predator but reduces fitness of prey
herbivory is a form of
predation

6. Parasitism – one species feeds on another  enhances
fitness of parasite but reduces fitness of host

7. Mutualism – two species provide resources or services
to each other  enhances fitness of both species

8. Commensalism – one species receives a benefit from
another species  enhances fitness of one species; no
effect on fitness of the other species

9. Symbiosis – two species live together  can include
parasitism, mutualism, and commensalism

10. Organizing ecological interactions
effect on species 1
predation
herbivory
parasitism + -
commensalism
mutualism
effect on
species 2
competition

11. Video Elements of Biology: Ecosystems: Organisms and Their Environment
Assignment: Ecological Interactions Quiz

12. 13.2 Research Questions
Name two ways in which members of the same species interact.
In what ways do members of different species interact?
Think of a biological community near you, and give an example of how population has affected another.
Explain how symbiotic relationships are similar to and different from predator-prey interactions.