Studied by 4 people
Population
The individuals that belong to the same species and live in a given area at a particular time.
Community
All of the populations of organisms within a given area.
Population ecology
The study of factors that cause populations to increase or decrease.
What are the 5 basic characteristics of any population?
Size, density, distribution, sex ratio, age structure
Population size (N)
The total number of individuals within a defined area at a given time.
Population density
The number of individuals per unit area at a given time.
Population distribution
A description of how individuals are distributed with respect to one another.
Sex ratio
the ratio of males to females in a population
age structure
a description of how many individuals fit into particular age categories
Population growth
the change in the size of a population over time
Can be positive or negative (still called growth)
Intrinsic growth rate
the maximum potential for growth of a population under ideal circumstances with unlimited resources.
r-selected species
A species that has a high intrinsic growth rate, which often leads to population overshoots and die-offs.
Quantity vs. quality of offspring.
Example: Frog
K-selected species
A species with a low intrinsic growth rate, the population increases slowly until it reaches carrying capacity.
Invest heavily into offspring to ensure survival.
Example: Elephant
Exponential growth
Growth whose rate becomes ever more rapid in proportion to the growing total number or size.
Exponential growth occurs when a population is provided unlimited resources and begins to grow at its intrinsic growth rate.
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
A growth model that describes a population whose growth is initially exponential, but slows as the population approaches the carrying capacity of the environment.
Carrying capacity
The limit of how many individuals in a population the environment can sustain.
What type of growth do K-selected species experience?
logistic growth
What type of growth do r-selected species experience?
they experience frequent boom and bust cycles due to their high intrinsic growth rates.
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. Predation or food availability.
Density independent factors
A factor that has the same effect on an individual's probability of survival and reproduction at any population size. Ex. Natural disasters.
uniform distribution
organisms spread out evenly. Territorial birds and some plants vying for resources tend to adopt this distribution.
Random distribution
displays no apparent pattern and is typical of many (but not all) plant communities especially forests.
Clumped distribution
this is typical of animals that live in groups such as meerkats or elephants
Survivorship
the probability that an individual organism will survive.
Survivorship curve
A graph that represents the distinct patterns of species survival as a function of age.
In a survivorship curve, organisms are divided into various cohorts which are plotted against survivorship.
Cohorts
groups of organisms who share a similar age.
Type I survivorship curve
A pattern of survival over time in which there is high survival throughout most of the lifespan, but then individuals start to die in large numbers as they approach old age.
Type II survivorship curve
A pattern of survival over time in which there is relatively constant decline in survivorship through most of the lifespan.
Type III survivorship curve
A pattern of survival over time in which there is low survivorship early in life with few individuals reaching adulthood.
Mathlusian theory
In 1798 Thomas Malthus predicted that human population would surpass the Earth's carrying capacity
Food production is linear
Population growth is exponential
Demography
The study of human populations and population trends.
cultural carrying capacity
Optimum level that would allow most people to live in reasonable comfort and freedom without impairing the ability of the planet to sustain future generations.
Immigration
The movement of people into a country or region, from another country or region.
Emigration
The movement of people out of a country or region.
Crude birth rate (CBR)
The number of births per 1,000 individuals per year.
Crude death rate (CDR)
The number of deaths per 1,000 individuals per year.
Population Growth Equation
(births + immigration) - (deaths + emigration)
The rule of 70
doubling time = 70/growth rate
Doubling time
The number of years it takes a population to double.
the percentage is what is needed in the denominator - DO NOT move the decimal when given a growth rate as a percentage!
true
Total fertility rate (TFR)
An estimate of the average number of children that each woman in a population will bear throughout her childbearing years.
Fecundity
the ability to produce an abundance of offspring or new growth; also known as Fertility.
Replacement-level fertility
The total fertility rate required to offset the average number of deaths in a population in order to maintain the current population size. Replacement level fertility tends to be higher in developing countries because mortality among young people tends to be higher.
Life expectancy
The average number of years that an infant born in a particular year in a particular country can be expected to live.
Infant mortality
The number of deaths of children before their first birthday per 1,000 live births.
Child mortality
The number of deaths of children under age 5 per 1,000 live births.
Net migration rate
The difference between immigration and emigration in a given year per 1,000 people in a country.
Theory of demographic transition
The theory that as a country moves from a subsistence economy to industrialization and increased affluence (wealth) it undergoes a predictable shift in population growth.
Pre-Industrial
Phase 1: Stable or Zero Population Growth (ZPG) because high birth rates and high death rates offset each other.
Transitional
Phase 2: The death rates drop rapidly, but birth rates do not change. Population growth is greatest at this point.. Rapid population growth because birth rates remain high but death rates decline because of better sanitation, clean drinking water, availability of food and health care.
Industrial
Phase 3 The birth rates decline and population growth slows. Slowing population growth as the economy and educational system improves and people have fewer children.
Demographic Trap
a point where birth rates remain high despite lowered death rates.
Post-Industrial
Phase 4. The population stops growing and sometimes begins to decline. Stabilizing population growth because the relatively high level of affluence & economic development encourage women to delay having children.
Family planning
The practice of regulating the number or spacing of children through the use of birth control.
IPAT equation
An equation used to estimate the impact of the human lifestyle on the environment:
Impact = Population × Affluence × Technology
Gross domestic product (GDP)
A measure of the value of all products and services produced in one year in one country. Used to measure the affluence of a nation.
Transects
a line that crosses an entire area when studying the distribution of a species
Quadrats
Square frame used for sessile organisms to determine species richness, population estimate
mark and recapture
Mark animal, return to environment and recapture it
Mark and recapture formula
Percent marked/100 x Number Marked / N (Population Estimate)
Removal sample
Take out species, which is not in their best interest, and don't return it
What does a rapid age structure diagram look like?
large at the bottom
What does a stable/zero growth age structure diagram look like?
What does a slow growth age structure diagram look like?
A triangular shape with a very large and wide base. Looks like rapid but it wider for much longer
What does a negative growth age structure diagram look like?
Larger at the top
Global population growth rate
(CBR-CDR)/10
Growth rate for a population or region
(CBR+Immigration)-(CDR+Emmigration) / 10
Note 
Flashcard (39)