AP Unit 3- Populations:

Population ecology

The study of factors that cause populations to increase or decrease

Species

A group of similar organisms

whose members freely interbreed and

produce fertile offspring

Community

All of the populations of organisms within a given area

Ecosystem

A community & its physical (abiotic environment)

Biotic potential

Under ideal conditions with unlimited resources available, every population has a maximum potential for growth

carrying capacity(k)

the limit to the number of individuals that can be supported by an existing habitat or ecosystem

Intrinsic growth rate (r) (biotic potential)

: The maximum potential for growth of a population under ideal conditions with unlimited resources.

Exponential growth model

A growth model that estimates a population’s future size after a period of time, based on the intrinsic growth rate and the number of reproducing individuals currently in the population.

J-shaped curve

The curve of the exponential growth model when graphed.

Limiting resource

a resource that a population cannot live without and that occurs in

quantities lower than the population would require to increase in size.

Logistic growth model

a growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment.

S-shaped curve

The shape of the logistic growth model when graphed.

Overshoot

When a population becomes larger than the environment’s carrying capacity

Die-off

A rapid decline in a population due to death;usually due to lack to resources leads to famine, disease, or conflict.

k-selected species

A species with a low intrinsic growth rate that causes the population to increase slowly until it reaches carrying capacity

R-selected species

A species that has a high intrinsic growth rate, which often leads to popualtion overshoot and dies off.

Density-dependent factor

A factor that influences an individual probability of survival and reproduction in a manner that depends on the size of the population.

Density-independent factor

A factor that has the same effect on a individual’s probability of survival and the amount of reproduction at any population size.

Survivorship curve

A graph that represents the distinct patterns of species survival as a function of age

Type ! survivorship cure(late loss)

A pattern of survival over time in which there is high survival throughout most of the life span, but then individuals start to die in large numbers as they approach old age.

Type 2 survivorship curve

A pattern of survival over time in which there is a relatively constant decline in survivorship throughout most of the life span

Type 3 survivorship curve(early loss)

A pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood

Demography

study of human

populations & population

trends

Immigration

movement of people into a country or region from another country or region

Emigration

movement of people out of a country or region

Doubling time

The number of years it takes a population to double, also known as Rule of 70

Total fertility rate

an estimate of average number of children each woman in a population will have throughout her childbearing years

Replacement-level fertility

total fertility rate required to offset the average numbers of deaths in a population in order to maintain the current population

Life expectancy

average # of years that an infant born in a particular ear in a particular country can be expected to live given the current average life span & death in that country

Infant mortality

number of deaths of children under the age of 1 per 1,000 live briths

Child mortality

number of deaths of children under the age of 5 per 1,000 live births

Net migration rate

the difference between immigration & emigration in a given year

per 1,000 people in a country

Type 1 survivorship curve(late loss)

A pattern of survival over time in which there is high survival throughout most of the life span, but then individuals start to die in large numbers as they approach old age.

Type 2 survivorship cure(constant loss)

A pattern of survival over time in which there I a relatively constant decline in survivorship throughout most of the life span

Type 3 survivorship cure(early loss)

A pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood

What did Thomas Malthus do?

He observed that the human population was growing exponentially, while the food supply we rely on was growing linearly. He believed that the human population would exceed the food supply & thus the carrying capacity of Earth.

Ecological footprint

the quality of nature it takes to support people or an economy and is a measure of sustainability

Demography

study of human population & population trends.

crude birth rate

the number of births per 1,000 individuals per year

crude death rate

the number of deaths per 1,000 individuals per year

theory of demographic transition

a theory that state a country moves from high to lower birth and death rates as development occurs and the country moves from a preindustrial to an industrialized economic system

population momentum

continued population growth after reduction measures have been implemented