Population Characteristics
The number of individuals of the same species living in the same area at the same time.
Population
The three patterns of population distribution.
Clumped, random, and uniform.
The three age groups shown in an age-structure diagram.
Prereproductive, reproductive, and postreproductive
Population growth occurs when this exceeds the death rate.
birth rate
The maximum growth rate of a population under ideal conditions.
Biotic potential
Resources such as food, water, shelter, and space influence this characteristic of populations.
Distrubtion
Population distribution in which individuals occur in groups because resources are patchy.
Clumped distribution
An age structure with more prereproductive than postreproductive individuals predicts this type of population trend.
Increasing population
If births equal deaths, the population will do this.
Remain stable
A graph showing the number of surviving individuals at different ages.
Survivorship curve
The number of individuals per unit area or volume.
Population density
Distribution pattern often caused by territorial behavior or competition.
Uniform distribution
An age structure with more postreproductive individuals than prereproductive individuals predicts this population trend.
Decreasing population
If the death rate exceeds the birth rate, the growth rate becomes this.
Negative
The table used to construct survivorship curves.
Life table
Population density generally decreases as this characteristic increases.
Body size
Distribution pattern in which individuals are scattered unpredictably.
Random distribution
Explain why replacement reproduction can still result in population growth in many LDCs.
Because many young individuals are entering their reproductive years, producing more births than deaths even if each couple has only enough children to replace themselves.
Calculate the growth rate if births = 30 per 1,000 and deaths = 10 per 1,000.
: 2%
Match each survivorship curve to its pattern: Type I, Type II, Type III.
Type I—high survival until old age; Type II—equal chance of death at all ages; Type III—high death rate early in life
Explain why members of a population are usually clumped throughout their geographic range.
They gather where resources such as food, water, and shelter are available.
Compare population distribution and population density.
Distribution describes how individuals are spaced (clumped, random, or uniform), while density measures the number of individuals per unit area or volume.
Compare the age structures of increasing, stable, and decreasing populations.
Increasing populations have many prereproductive individuals, stable populations have similar numbers in all age groups, and decreasing populations have many postreproductive individuals.
Explain why growth rate alone does not completely determine future population size.
Population growth is also influenced by age structure, demographics, and resource availability.
List the five factors that influence a population's biotic potential.
Availability of resources, number of offspring per reproductive event, survival until reproductive age, frequency of reproduction, and age at first reproduction.