BIOSC 0370 Lecture Notes - Lecture 21: Frederic Clements, Transect, Species Evenness
22 Dec 2015
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Ch 18 concept #1: communities can have distinct or gradual boundaries. Community: assemblage of species living together in an area. Community zonation can be caused by both biotic and abiotic processes. Communities are often categorized by their dominant organisms or by physical conditions that affect the distribution of species. Interdependent communities: communities in which species depend on each other to exist. Independent communities: communities in which species depend on upon each other to a much lesser extent. Plant biologist frederic clements proposed that most communities are interdependent and act as superorganisms (discrete unit) due to a large array of interactions among the species. Plant biologist henry gleason proposed that most communities consist of species with independent distributions where species distributions rely mainly on tolerance to underlying environmental conditions. If species distributions are independent, they should depend only on individual habitat requirements; there should be gradual changes in species along a line transect.
