Limiting Factors
NGSSS: SC.912.L.17.5 Analyze how population size is determined by births, deaths,
immigration, emigration, and limiting factors (biotic and abiotic) that determine carrying
capacity. AA (Also addresses SC.912.N.1.4)
Background:
A variety of factors affects the ability of wildlife to successfully reproduce and to maintain
their populations over time. Disease, predator/prey relationships, varying impacts of
weather conditions from season to season (e.g., early freezing, heavy snows, flooding, and
drought), accidents, environmental pollution, and habitat destruction and degradation are
among these factors.
Some naturally-caused as well as culturally-induced limiting factors serve to prevent wildlife
populations from reproducing in numbers greater than their habitat can support. An excess
of such limiting factors, however, leads to threatening, endangering, and eliminating whole
species of animals. The most fundamental of life’s necessities for any animal are food,
water, shelter, and space in a suitable arrangement. Without these essential components,
animals cannot survive.
Wildlife populations are not static. They continuously fluctuate in response to a variety of
stimulating and limiting factors. Natural limiting factors tend to maintain populations of
species at levels within predictable ranges. This kind of “balance in nature” is not static, but
is more like a teeter-totter than a balance. This cycle appears to be almost totally controlled
by the habitat components of food, water, shelter, and space, which are also limiting
factors. Habitat components are the most fundamental and thereby the most critical of
limiting factors in most natural settings.
Problem Statement: How will resource availability affect the population of a species in an
ecosystem?
Vocabulary: reproduction, predator, prey, degradation, limiting factor, habitat, species,
population, resource, carrying capacity
Materials (per group):
• open space
Procedures:
1. Make a hypothesis based on the problem statement above for the resources being
supplied.
2. Obtain a number (1 through 4) from your teachers.
a. Deer = 1
b. Resources = 2, 3, 4
3. Go outside. Deer will all stand on one side of the sidewalk and all the resources will
stand on the opposite side. Stand with backs toward other group.
