Do Now – 3 Minutes
Topic – Range of Tolerance (con’t)
• Yesterday we talked about one abiotic
factor in which the extreme makes it
difficult for humans to survive in.
• What are two other abiotic factors that
affect the survivability of humans?
Bell Curve
 The length, or range, of this graph for
creatures is known as its range of tolerance.
 For every abiotic component in an ecosystem,
a given population/species has a range of
tolerance, or set of specific conditions that
are suitable for that species.
Representation of Range of
Tolerance
Terms
 Zone of Intolerance – Zone where organisms
cannot survive
 Zone of Physiological Stress – Zone where small
numbers can survive these difficult conditions
Terms
 Optimum – zone where a stable healthy
population survives
Example
 Humans have a Range of Tolerance for
atmospheric oxygen.
 If we receive too little or too much oxygen, we
become dizzy and disoriented.
 If we do not re-enter the
Optimum Zone, we die.
 15-19 percent: Decreased ability to work strenuously. May
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

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impair coordination and may induce early symptoms with
individuals that have coronary, pulmonary, or circulatory
problems.
12-15 percent: Respiration and pulse increase; impaired
coordination, perception, and judgment occurs.
10-12 percent: Respiration further increases in rate and
depth; poor judgment and bluish lips occur.
8-10 percent: Symptoms include mental failure, fainting,
unconsciousness, an ash-colored-face, blue lips, nausea,
and vomiting.
6-8 percent: 8 minutes - 100 percent fatal;
6 minutes - 50 percent fatal; 4-5 minutes - recovery with
treatment.
4-6 percent: Coma in 40 seconds, convulsions, respiration
ceases - death.
Example
 Using the terms:
 Range of Tolerance
 Zone of Intolerance
 Abiotic Factors
 Explain what geese do
in Winter months and
why.
Example
 Temperature of the Earth
Lab-like Activity
 To see this graphically even further, I
have this activity regarding rainbow trout,
and their range of tolerance on two
abiotic factors.
 This can show how certain species act as
indicators within a community.
Lower limit
of tolerance
Few
organisms
Abundance of organisms
Upper limit
of tolerance
Few
organisms
No
organisms
Population Size
No
organisms
Range of Tol.
Zone of
Zone of
intolerance physiological stress
Low
Optimum range
Temperature
Zone of
Zone of
physiological stress intolerance
High
Range of tolerance for a population of organisms, such as fish,
to an abiotic environmental factor—in this case, temperature.
Sharing the Wealth
 When we examine organisms in the
same community, we can begin to see
populations with similar ranges of
tolerance living with each other.
Hemlock
Red Maple
Mtn. Table Pine
Sharing the Wealth
 What are some potential issues about
organisms residing in the same tolerance
area?
 Imagine what could happen these
creatures.