ECOLOGY INTERACTIONS

Types of ecological interactions

competition

predation

parasitism

mutualism

commensalism

symbiosis

Competition – two species share a requirement for alimited resource reduces fitness of one or both species

Predation – one species feeds on another enhancesfitness of predator but reduces fitness of prey

herbivory is a form ofpredation

Parasitism – one species feeds on another enhancesfitness of parasite but reduces fitness of host

Mutualism – two species provide resources or servicesto each other enhances fitness of both species

Commensalism – one species receives a benefit fromanother species enhances fitness of one species; noeffect on fitness of the other species

Symbiosis – two species live together can includeparasitism, mutualism, and commensalism

Organizing ecological interactions

effect on species 1

effect onspecies 2

+ 0 -

+

0

-

mutualism

predationherbivoryparasitism

predationherbivoryparasitism

commensalism

commensalism

competition

competition

competition

VIDEO

• Elements of Biology: Ecosystems: Organisms and Their Environment• http://www.pbs.org/wnet/nature/lessons/symbiotic

-strategies/video-segments/1496/• Assignment: Ecological Interactions Quiz

13.2 RESEARCH QUESTIONS

1) Name two ways in which members of the same species interact.

2) In what ways do members of different species interact?

3) Think of a biological community near you, and give an example of how population has affected another.

4) Explain how symbiotic relationships are similar to and different from predator-prey interactions.