Population Ecology Flashcards (Currier/Morano/Chi)

Biotic factors

Parts of an ecosystem that are living or used to be living

Abiotic factors

Parts of an ecosystem that have never been living

Habitat

The specific environment in which an organism lives

Population

a group of individuals that interbreed and produce fertile offspring

Population

members of a species that live in the same area

Niche

An organism's role in its environment.

Ecosystem

Community

all the populations in a particular area

Population Size

The number of individuals in a population at a given time

Population Density

the number of individuals within a population per unit area

Population Distribution

How organisms are arranged within an area

random distribution

Organisms arranged in no particular pattern

Uniform distribution

Organisms evenly spaced

Clumped distribution

Organisms grouped near resources; most common distribution in nature

Age Structure

Relative number of organisms of each age group within population

Sex Ratios

Proportion of males to females

Survivorship Curves

A population's relative birth and death rates (mortality and natality) affect how it grows.

r selected populations

live in unstable environments, have a short lifespan, have many offspring, are small, and provide little to no parental care

k selected populations

live in stable environments, have a long lifespan, have few offspring, are larger, and provide long parental care

Migration

seasonal movement into and out of an area, can temporarily affect population size

Immigration

occurs when an outside population enters an existing population

emigration

occurs when part of a population leaves

exponential growth

occurs when a population increases by a fixed percentage every year

logistical growth

occurs when growth almost always slows and stops due to limiting factors.

carrying capacity

the largest population size that an environment can sustainably support

species

a group of individuals that interbreed and produce fertile offspring

ecosystem

all the living things and their physical environments within a particular area

limiting factor

characteristic of the environment that restricts population growth

density dependent factors

biological variables whose effects on a population's growth or size change depending on how crowded the population is (i.e., competition and disease)

density independent factors

environmental forces that change the size of a population regardless of how crowded or dense that population is (i.e., pollution, weather, natural disasters like wildfires)