COMMUNITY ECOLOGY cont pp Warm-up 4/2: Define Inter and Intraspecies competition. Which has greater competition? Explain Explain why parasites and hosts are considered to be a good example of co- evolution.

Species (organism) Population Community (interaction of different species) Ecosystem Biosphere

PROPERTIES OF A COMMUNITY Species Richness Species evenness Species- Area Effect

Species Richness: # of different types of species varies with latitude (closer to equator the more species) more sun, better climate stability

Species evenness: the abundance of each species

↑species richness and ↑ evenness: ↑ stability (ability to withstand disturbances in the ecosystem)

Species- Areas Effect: larger areas contain more species than smaller areas

KEYSTONE SPECIES most dominant species in the community Dictates community structure Demonstrated by removal of keystone species from community What would happen to the species richness if the keystone species is removed from the ecosystem?

SUCCESSION Sequential and gradual growth of a community Two types: primary and secondary

Primary succession occurs when land is first formed. 1. Microbes, lichens and mosses must create soil before other plants can grow. 2. Pioneer species: first species to dominate early in succession (small and fast growing)

Secondary succession occurs when succession must start over after the destruction of a climax community (marked by the domination of long-lived species and great diversity). - takes place on sites that have already supported life

Homework Read pp P 410 #1-5, 8 Due Thursday