CH.+53+Community+Ecology

Chapter fifty three is based on community ecology. It covers species interaction, species diversity, disturbances that affects a species, biographic factors that affect community biodiversity, and lastly the contrasting views of community structure. Species interaction happens through competing for resources, predation(killing another species), herbivory(eating plants of algae), parasitism(relying on another species for nourishment), or disease. Species diversity can affect the communication of species, along with the impact they have on one another. Dominant species can usually control the community structure they live in. The dominant species is the most abundant in the community because they are equipped with the most competitive abilities. A keystone species are the least abundant because they have a incommensurate influence on community structure. Food webs and chains are introduced with the dominant and keystone species. When disturbances happen in a community, a species will relocate, often affecting the other species communities. This is called ecological succession and biodiversity is created. The two biographic factors that affect community biodiversity are geographic location and size of the area. The last section of the chapter covers the contrasting views of community structure. Many argue how a species became grouped together in a community. There are two different types of ideas, each with two different, but similar hypothesis.The first individual hypothesis states that the species within a community are locked into particular biotic interactions while the individual hypothesis says that communities are loosely organized associations of independently distributed species with the same abiotic requirements. The other side of the argument are rivet and redundancy models.The rivet models states that all the species in a community are linked together in a tight web of interactions so that the loss of even a single species affects the other species in that community strongly. The redundant model suggests that if a species is lost from a community another species will come to take its place.

Core themes of biology:

Interdependence of nature: An organism can react and communicate with one another and its habitat. Continuity and change: a species will come and take the place of another species. Energy Transfer: Food is transferred to energy from primary producers to the consumers. Food chain related.

http://www.geo.arizona.edu/Antevs/ecol438/lect05.html Everything about community ecology. Tons of pictures and graphs.

http://media-2.web.britannica.com/eb-media/48/6548-004-4D277914.gif Picture of predators and other keystone species of the ocean.