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Limits to Growth
Vocabulary • There are many different
factors that can limit the
population growth.
Limiting
factor
• A factor that causes
population growth to
decrease is called limiting
factor.
Types of Limiting factors
Vocabulary
Density-dependent
limiting factors
1. Density-Dependent limiting
factors.
a) They depend on population
size.
b) They become limiting only
when the population density
reaches a certain level.
c) They include competition,
predation, parasitism, and
disease.
Vocabulary
• Density-Dependent Limiting
Factors
1. Competition: When a population
becomes crowded, organisms
compete, or struggle, with one another
for food, water, space. Competition
can also occur between members of
different species. Two species cannot
occupy the same niche at the same
place and time.
Predator-prey 2. Predation: Populations in nature are
often controlled by predation.
relationship
Predator-prey relationship
3. Parasitism and disease: Parasites and
disease are easier to transmit in a
large, and dense population
Figure 5-7 Wolf and Moose
Populations on Isle Royale
Predator-Prey Relationship
Section 5-2
60
2400
50
2000
40
1600
30
1200
20
800
10
400
0
1955
1960
1965
1970
1975
Moose
Go to
Section:
1980
Wolves
1985
1990
1995
0
Vocabulary
2. Density-independent
limiting factors.
Density-Independent
limiting factors
a) They affect all
populations in similar
ways regardless on the
population size.
b) They include unusual
weather, natural
disasters, seasonal cycles,
and certain human
activities (damming
rivers, and clear-cutting
forests).
Populations
DensityDependent factors
Predation
Density-Independent
factors
Competition
Parasitism
and
disease
Unusual
weather
Natural
disasters
Some
human
activities