Unit 3 vocab

Population growth rate

The number of offspring an individual can produce in a given time period, minus the deaths of the individual or its offspring during the same period. (also known as intrinsic growth rate)

Biotic potential

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

K-selected species

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

• Low reproductive rates

• Huge parental care

• Longer life spans

• Large body sizes

(Ex: Humans, elephants, whales, trees)

Carrying capacity

The limit to the number of individuals that can be supported by an existing habitat or ecosystem, and is denoted as K

R-selected species

A species that has a high intrinsic growth rate, and their population typically crease rapidly

• High reproductive rates

• Low parental care

• Smaller body sizes

• Shorter life spans

(Ex: Sea horses, bacteria, insects, weeds)

Overshoot

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

Dieback

A rapid decline in a population due to deaths. Happens after overshoot (Also known as die-off)

Survivorship curve

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

Type l survivorship curve

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

(Ex: Humans, elephants, whales, captive animals bc they don’t have to worry about predation or lack or food, etc)

Type ll survivorship curve

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

(EX: Songbirds, small mammals like rodents, certain reptiles)

Type lll survivorship curve

A pattern of survival over time in which there a high death rate early in life with few individuals reaching adulthood

(EX: Oysters, herring, insects)

Density-dependent factor

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

(Ex: Species may suffer bc of predation from other species, or lack of resources bc of competition from other species)

Density-independent factor

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

(EX: Natural disasters)

Population growth models

Mathematical equations that can be used to predict population size at any moment in time

Fecundity

The ability to produce an abundance of offspring

Exponential growth model

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

J-shaped curve

The curve of the exponential growth model when graphed

Logistic growth model

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

S-shaped curve

the shape of the logistic 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

Life expectancy

The avg number o years that an infant born in a particular year in a specific country can be expected to live, given the current avg life span and death rate in that country

demography

The study of human populations and population trends

Demographer

scientific in the field demography

Emigration

the movement of people out of a country or region

Immigration

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

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 yr

net migration rate

the difference between immigration and emigration in a given yr per 1,000 ppl in a country

Life expectancy

The avg number of years that an infant born in a particular country can be expected to live, given the current avg life span and death rate in that country

Infant mortality

The number of deaths of children under 1 year of age per 1,000 live births

Child mortality

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

Environmental justice

the study of disproportionate exposure to environmental hazards experienced by people of color, recent immigrants and people of lower socioeconomic backgrounds; and is both an academic field and a social movement

Age structured diagram

A visual representation of the number of individuals within specific age groups for a county, typically expressed for males and females

Population pyramid

An age structure diagram that is widest a the bottom and smallest at the top, typical of developing countries

Developing countries

countries with relatively low levels of industrialization and income

developed countries

countries that have relatively high levels of industrialization and income

population momentum

continued population growth after growth reduction measures have been implemented

total fertility rate (TFR)

an estimate of the avg number of children that each woman in a population will ber throughout her childbearing years

Family planning

the regulation of the number or spacing of offspring through the use of birth control

replacement level fertility

the total fertility rate required to offset the avg number of deaths in a population in order to maintain the current population size

doubling time

the number of years it takes a population to double

rule of 70

a method which dictates that by dividing the number 70 by the percent population growth rate we can determine a population’s doubling time

Theory of demographic transition

a model that changes in a country's population. It states that the population will eventually stop growing when the country transitions from high birth rates and high death rates to low birth rates and death rates, stabilizing the population.

IPAT equation

A conceptual representation of the three major factors that influence environmental Impact:Population of humans, Affluence, Technology