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Name: ____________________________________
Date: ___________________
Chapter 5 Notes – Populations
Section 5-2 Limits to Growth (p. 124-127)
Limiting Factors
What factors limit population growth?
An ecosystem’s productivity can be reduced when there is an insufficient supply
of a particular ______________________.
•
Ecologists call such substances ____________________ nutrients.
A limiting nutrient is an example of a more general ecological concept called a
limiting factor =
Density-Dependent Factors
Density-dependent limiting factor =
Include:
•
_______________________
•
_______________________
•
_______________________
•
_______________________
Density-dependent factors operate when the population _______________
reaches a certain level.
•
These factors operate most strongly when a population is _____________
and _______________.
•
Do not affect ________________, scattered populations that much.
Competition
When populations become crowded, organisms compete for _____________,
________________, ________________, ______________________, and other
essentials.
•
Can occur among members of the _____________ species and between
members of _____________________ species.
1
o Between different species: can lead to _________________________
change; species may evolve different ______________.
Predation
•
Populations in nature are often controlled by predation.
•
A ___________________-____________ relationship is the best-known
mechanism of population control.
Does this predatory-prey population graph correlate to the wolf/deer population activity
that you did?
Parasitism and Disease
•
Parasites can _____________ the growth of a population.
•
A parasite can live in or on another organism (the _____________) and
consequently ______________ it.
Density-Independent Factors
Density-independent limiting factors =
Examples:
•
unusual _________________
•
natural __________________
activities (damming rivers,
•
seasonal ________________
clear-cutting forests)
•
2
certain _______________