Factors Remember primary productivity of an ecosystem can be reduced by limiting nutrients Limiting factors can determine carry capacity Density Dependent Factors Density Independent Factors ID: 712965
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Slide1
5-2 Limits to GrowthSlide2
Limiting Factors
Remember, primary productivity of an ecosystem can be reduced by limiting nutrients
Limiting
factors can
determine carry capacity
Density Dependent Factors
Density Independent FactorsSlide3
1. Density-Dependant Factors
Limiting factors that depend on population size
Density-dependent
factors become limiting only when population density reaches a certain
level
Does
not affect small, scattered populationsSlide4
1a. Competition
Occurs when populations become
crowded
When 2 species compete for same resource, they are under pressure to change
Over time, evolve to occupy diff. nichesSlide5
1b. Predation
Populations in nature are controlled by predation
Known as predator-prey relationshipSlide6
Isle Royale in Lake SuperiorSlide7
1c & 1d Parasitism & Disease
Parasites
are similar to predators – weaken and kill hosts
Large populations can be under stress making them more susceptible to
diseases
More members = easier to pass “things” aroundSlide8
3. Density-Independent Factors
Factors
that affect populations regardless of their
size
Examples:
Unusual
weather (Draught, Hurricanes)
Season cyclesHuman activities (damming rivers,
forest cutting
)Slide9
5-3 Human Population Growth
Like the populations of many other living organisms, the size of the human population tends to increase with time.
For most of human existence, the population grew slowly
Until fairly recently, only half the children in the world survived to adulthood. Slide10
What caused human populations to suddenly grow rapidly?
Agriculture
Industry/MedicineSlide11
About
500 years ago, the human population began growing more
rapidly
because of agriculture and industry.
With
these advances, the human population experienced exponential
growthSlide12Slide13
Patterns of Population Growth
English economist Thomas Malthus observed that human populations were growing rapidly.
Malthus predicted that such growth would not continue indefinitely.
Malthus
-
war, famine, and disease would limit human population growth
.Slide14
Demographic Transition
The scientific study of human populations is called
demography
Demographic
transition
, a dramatic change in birth and death
rates.
Ex: U.S., Japan, EuropeSlide15Slide16Slide17
What are the 4 density-dependent limiting factors?
Predation
Disease
Competition
ParasitismSlide18
What are examples density independent limiting factors?
Storms
Natural Disasters
Human activitySlide19
What caused the human population to grow rapidly?
Agriculture
Industry
Medicine