This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.View Full Document
Unformatted text preview: Community Ecology: Chapter 54 A biological community is an assemblage of populations of various species living close enough for potential interaction Ecologists call relationships between species in a community interspecific interactions Examples are competition, predation, herbivory, and symbiosis Interspecific interactions can affect the survival and reproduction of each species, and the effects can be summarized as positive (+), negative (), or no effect (0) Interspecific competition (/ interaction) occurs when species comppete for a resource in short supply Can occur between similar species (different plant species in a garden competing for soil nutrients) or very different species (grasshoppers and bison competing for resources) Strong competition can lead to competitive exclusion , local elimination of a competing species The competitive exclusion principle states that two species competing for the same limiting resources cannot coexist in the same place The total of a species use of biotic and abiotic resources is called the species ecological niche An ecological niche can also be thought of as an organisms ecological role Ecologically similar species can coexist in a community if there are one or more significant differences in their niches Character displacement is a tendancy for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species An example is variation in beak size between populations of two species of Galpagos finches Predation (+/ interaction) refers to interaction where one species, the predator, kills and eats the other Some feeding adaptations of predators are claws, teeth, fangs, stingers, and poison Prey display various defensive adaptations Behavioral defenses include hiding, fleeing, forming herds or schools, self defense, and alarm calls Animals also have morphological and physiological defense adaptations Cryptic coloration , or camouflage, makes prey difficult to spot...
View Full Document
- Spring '07