GEOG 1400 Study Guide - Midterm Guide: Commensalism, Parasitism, Dendrochronology
Document Summary
Cholla and grasses: cholla are very prickly desert plants which receive benefit from being found with nurse grasses (e. g. shade, moisture) and in turn protect the grasses from predation. Species interactions can change over time: e. g. If the saguaro establishes, it eventually will outcompete the nurse plant for water due to its extensive shallow root system and the nurse will die: = predation-like interaction. White pine: establish with poor soil, but full sun, were able to quickly colonize the bare ground left behind after deglaciation. Eastern hemlock: establish in better soils and in the shade, moved northwards ~1000 years after white pines after soils became better and other species provided shade. The theory of island biogeography developed by macarthur and wilson in 1967. Large islands tend to support more species than smaller islands: larger area more resources and niches available, extinction varies with island area.
