Species Interactions

5 major types of symbioses-Close interactions among species.

• Predator captures, kills, and consumes prey.• Determines relationships in food web.• Regulates population size.• Adaptation in predators and prey due to

Natural Selection.

Mimicry

Herbivores are predators, plants prey!

• Plants have defenses as well. Secondary compounds = toxic but can be medicinal.

• Stinging Nettle Night Shade

Parasitism

• Parasite benefits, host is harmed.• Ecto – outside Endo- inside

Mutualism

• Both species benefit.

Commensalism

• One species benefits, the other is “neutral”

Competition

• Results from niche overlap- use of same limited resource by 2 or more SPECIES.

• Competitive Exclusion – 1 species uses resource and other is eliminated (NS)

• Character Displacement – Evolution of anatomical differences that reduce competition between similar species.

• Resource Partitioning- reduced competition.

Competitive Exclusion

Character displacement

Succession- gradual sequential growth of species in an area

• Primary Succession – Development of a community in an area that has not supported life previously.

• Secondary Succession – DUH! Sequential replacement of species that follows a disruption of an existing community.

• Pioneer Species – predominate early in succession, tend to be small, fast-growing, fast reproducing.

• Climax community –DUH!