Unit 3: Populations

Flashcards covering key concepts from the Populations lecture notes.

Population

A group of organisms of the same species.

Population Density

The number of individuals of a population that inhabit a certain unit of land or water area.

Population Dispersion

How individuals of a population are spaced within a region.

Clumped Dispersion

The most common dispersion pattern for populations, adhering to the 'those of a feather flock together' idea.

Uniform Dispersion

Members of a population are uniformly spaced throughout their geographic region, usually due to competition for resources.

Random Dispersion

A relatively uncommon pattern of dispersion where the position of each member is not determined by others.

Biotic Potential

How much a population would grow if there were unlimited resources in the environment.

Carrying Capacity

The maximum population size that can be supported by the available resources in the region.

J-Curve Model

What type of population growth model is represented by an exponential growth?

Logistic Population Growth

What type of population growth is known as the (S-Curve)?

Rule of 70

A method to approximate the time it takes for a population to double by dividing 70 by the current growth rate.

R-selected Organisms

Organisms that reproduces early in life and usually have a high capacity for reproductive growth with little to no care given to offspring.

K-selected Organisms

Organisms that reproduces later in life, produces fewer organisms, and devote significant time and energy to nurturing offspring.

Boom-and-Bust Cycle

A population cycle characterized by a rapid increase followed by an equally rapid drop-off, common among r-strategists.

Predator-Prey Cycle

What type of population cycle involves the interaction between predator and prey populations?

Density-dependent Factors

Factors influencing population growth that are affected by the density of the population, such as increased predation, competition, disease, and buildup of toxic materials.

Density-independent Factors

Factors influencing population growth that are not affected by the density of the population, such as fires, storms, and earthquakes.

Type I Survivorship Curve

Survivorship curve where the majority of offspring live for a long period of time before dying off.

Type II Survivorship Curve

Survivorship curve where offspring have a 50-50 chance of surviving to old age.

Type III Survivorship Curve

Survivorship curve where most offspring die young, but if they live to a certain age, they will live a longer life.

Birth Rate

The number of live births per 1,000 members of the population in a year.

Death Rate

The number of deaths per 1,000 members of the population in a year.

Emigration

The movement of people out of a population.

Immigration

The movement of people into a population.

Total Fertility Rate (TFR)

The number of children a woman in a given population will bear during her lifetime.

Replacement Birth Rate

The number of children a couple must have in order to replace themselves in a population.

Ecological Footprint

Used to describe the environmental impact of a population.

I=PAT (Impact = Population * Affluence * Technology)

What does IPAT stand for?

Green Revolution

The technological innovation and increased use of pesticides and fertilizers, which allowed farmers to increase crop production.

Extensive Pastoralism

The shifting of animal herds between grazing pastures in arid parts of the world.

Population Pressure

Too many people and too many animals on too little land.

Overgrazing

Led to significant amounts of dry grassland being denuded, eroded, and desertified.

Desertification

Any human process that turns a vegetated environment into a desert-like landscape.

Soil Salinization

The salt content in soil increasing due to non-anthropogenic and/or anthropogenic influences.

Irrigation

The application of controlled amounts of water to plants at needed intervals.

Aquifers

Underground water tables.

Deforestation

The act of clearing a forested area of trees and other vegetation without the intention of replanting.

Vulnerable Species

A species likely to become endangered if no action is taken.

Endangered Species

A species likely to become extinct.

Critically Endangered

A species at a very high risk of extinction.

Fragmentation

Habitats broken into smaller pieces by, for example, building of roads and cities.

Degradation

Pollutants are added to the environment.

Overexploitation

Contributing to extinction through excessive harvesting or use of a species.

HIPPCO

An acronym to memorize the causes of extinction: Habitat Destruction/Fragmentation, Invasives, Population, Pollution, Climate Change, Overharvesting/Overexploitation.