Ecology 1: Population Ecology (E2) Flashcards
Ecology
The study of the rules of engagement
(Seeks to explain why the world works and acts the way it does)
Environment
The surroundings or conditions in which an organism lives
Abiotic
Non living aspects of the environment
Ex.space, sunlight, heat, wind, water currents, etc
Biotic
Living aspects of the environment
Ex.other organisms, parasites
Density
The number of individuals per unit area or volume
(Not a static property of populations…it changes)
Ex.births, deaths, immigration, emigration
Dispersion
Describes patterns of distribution within a species geographical range
Clumped dispersion
Individuals live areas of high local abundance separated by areas of low abundance
Uniform dispersion
Inidividuals are uniformly spaced throughout the environment
Random dispersion
Individuals have an equal chance of living anywhere within the geographic range of population
Life table
Summarize survival and reproduction of a cohort
Resource
Environmental factors that an animal uses directly
expendable(food) and non expendable(sunlight, physical space)
Population
A group of individuals of a single species living in the same general area or geographical range
Immigration
Species coming into land
Emigration
Species leaving land
Demography
Study of population growth
Survivorship curve
Plots the proportion or numbers in a cohort still alive at each age
(Graphical representation of a life table)
Semalparity
Only one reproductive cycle in its lifetime
Iteoparity
More than one reproductive cycle
Population growth(exponential, logistic)
Difference between rates of birth and death
Exponential(idealized, dN/dt=rN, rate at which a population is increasing in size at each moment in time) vs logistic(realistic, describes how populations grow as resources are used up)
Intrinsic rate of increase
Per capita change on population
Carrying capacity
The largest population the limiting resource can support
Limiting resource
Resource that is depleted first
Density independent factors
All members of a population independent of age age or population size (abiotic)
Independent of popn size so cannot truly regulate popn growth, random
Ex.age, structure, sex ratio, growth
Density dependent factors
Responds to density of the population predators, parasites, disease, competition (biotic)
Ex.Density increases, effects of disease/parasites increase
Ex. Competition between species for a common resource lowers the effective carrying capacity for each species
