Principles of Ecological Factors Range of Tolerance-any variation in the physical or chemical environment that an organism can withstand before it is killed/harmed耐受范围 Lower limit Upper limit of tolerance of tolerance No Few Few No organisms organisms Abundance of organisms organisms organisms oks/Cole-Tho Zone of Zone of Optimum range Zone of Zone of intolerance physiological stress physiological stress intolerance Low Temperature High Principles of Ecological Factors Principles of Ecological Factors Fig. 4-14 p. 73; Refer to Fig. 4-13 p. 73 Fig. 4-14 p. 73; Refer to Fig. 4-13 p. 73 Range of Tolerance- any variation in the physical or chemical environment that an organism can withstand before it is killed/harmed 耐受范围