Terms in this set (48)
A major sub-field of ecology that deals with the dynamics of species populations and how these populations interact with the environment.(how they compete for food,perdition,disease)
Aspects of population important to success
how they compete for food,perdition,disease,reproductive success, how population affects communities
The number of individuals of a species per unit of area or volume at a give time.
The statistical study of human populations.
The maximum reproductive capacity of a population if resources are unlimited. Also called intrinsic rate of increase.
Factors that prevent species from over populating, such as limited food. (it is a negative feedback mechanism, as population increases so does resistance)
Carrying capacity K
The maximum number of individuals a particular environment can support. When r approaches 0
K- selected species
Strong competitors in crowded niches, and invest more heavily in fewer offspring, each of which has a relatively high probability of surviving to adulthood.
Species with this reproductive strategy reproduce quickly and have many offspring, most of which usually do not survive very long.
The probability that a given individual in a population will survive to a particular age, three different types. I II III
Density dependent factors
An environmental factor that affects the size of a population and is impacted by changes in population density. Examples include food availability, predation and disease.
Boom bust cycle
A pattern of population growth in which exponential growth leads to a period when the population exceeds its carrying capacity, causing the population to decrease rapidly or crash
Density independent factor
A factor that affects the size of the population regardless of the population density ex. climate, drought, floods, hurricanes
The amount of time it would take for a population to double in size, assuming its current growth rate does not change. Rule of 70 is that 70 divided by the percent annual growth in population tells you how many years it will be before a population doubles.
Infant mortality rate
The number of infant deaths under age 1 per 1,000 live births.
Countries where infant mortality rates are higher than highly developed countries.
A model describing population growth that levels off as population size approaches carrying capacity
The number of children a couple must produce to "replace" themselves.
Total fertility rate
The average number of children born per woman, given the population's current birth rate.
Consists of four demographic stages in which a population progresses as its society becomes industrialized.
The second demographic stage that has a lowered death rate.
The number and proportion of people at each age in a population.
Population growth momentum
The potential for future increases or decreases in a population based on the present age structure.
Immigration and Nationality Act
Act passed that regulated immigration into the United States.
Immigration Reform and Control Act
Act that abolished national quotas and gave three groups of people priority when immigrating to the United States.
Crude birth Rate
Nativity or childbirths per 1,000 people per year.
Crude death Rate
A measure of the number of deaths in some population, scaled to the size of that population, per unit time.
Population growth rate
The change in a population over time, and can be quantified as the change in the number of individuals of any species in a population.
The accelerating population growth that occurs when optimal conditions allow a constant reproductive rate over a period time.
Pre Industrial Stage
Birth and death rates high, population grows slowly, infant mortality high
(demographic transition) decline in birth rate, population growth slows
Post Industrial Stage
the fourth and final stage of the demographic transition model, in which both birth and death rates have fallen to a low level and remain stable there, and populations may even decline slightly
Highly Developed Countries
countries with complex industrialized bases, low rates of population growth, and high per capita incomes
Less Developed Countries
Also known as developing country, a country that is at a relatively early stage in economic development
(b) number of births per 1000 people per year
(d) number of deaths per 1000 people per year
(r) b-d also called the natural increase in human population
movement of population from one region to another
immigration (i), emigration (e)
two types of dispersal in which individuals enter a population and increase its size
growth rate formula including immigration
intrinsic rate of increase
max rate that a population could increase under ideal conditions
age that reproduction begins, fraction of lifespan that an individual can reproduce, # of reproductive periods per lifespan (aka life history characteristics)
factors that determine intrinic rate of increase
exponential population growth
Growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time.
logistic population groth
S shaped graph, exponential growth initially followed by a leveling out as the carrying capacity is reached
a sudden population decline caused by predation, waste accumulation, or resource depletion
an age-specific summary of the survival pattern of a population
scientific study of human populations structure and growth
zero population growth
when the birth rate equals the death rate