population
group of individuals/organisms of the same species living in a particular area
community
populations of all species living and interacting in an area at a particular time
Niche
total way of life or role of species in an ecosystem. It includes all physical, chemical, and biological conditions that a species needs to live and produce in an ecosystem.
Habitat
place or type of place where an organism or population of organisms live
competition
two or more individual organisms of a single species or two or more individuals of different species attempting to use the same scarce resources in the same ecosystem
interspecific competition
attempts by members of two or more species to use the same limited resources in an ecosystem
intraspecific competition
attempts by two or more organisms of a single species to use the same limited resources in an ecosystem.
competitive exclusion/Gause's Principle
two species that compete for the exact same resource cannot stably coexist.
Realized Niche
parts of the fundamental niche of a species that are actually used by that species
fundamental niche
full potential range of the physical, chemical, and biological factors a species can use if it does not face any competition from other species
predation
situation in which an organism of one species captures and feeds on all or part of an organism of a different species
symbiotic relationship
relationship between two entities which is mutually beneficial for the participants of the relationship
mutualism
type of species interaction in which both participating species generally benefit
commensalism
interaction between organisms of different species in which one type of organism benefits and the other type is neither helped nor harmed to any great degree
parasitism
interaction between species in which one organism, called the parasite, preys on another organism, called the host, by living on or in the host
biotic balance
an ideal condition in which the interrelationships of organisms to one another and their environment appear harmonious, like a climax forest.
keystone species
species that play roles affecting many other organisms in an ecosystem
indicator species
species that serve as early warnings that a community or ecosystem is being degraded
indigenous species
species native to a given region or ecosystem if its presence in that region is the result of only natural processes, with no human intervention
invasive species
species that migrate into an ecosystem or are deliberately or accidentally introduced into an ecosystem by humans
ecological succession
process in which communities of plant and animal species in a particular area are replaced over time by a series of different and often more complex communities
primary succession
ecological succession in a bare area that has never been occupied by a community of organisms
secondary succession
ecological succession in an area in which natural vegetation has been removed or destroyed but the soil is not destroyed
pioneer species
first hardy species often microbes, mosses, and lichens, that begin colonizing a site as the first state of ecological succession
Climax community
fairly stable, self-sustaining community in an advanced stage of ecological succession; usually has a diverse array of species and ecological niches; captures and uses energy and cycles critical chemicals more efficiently than simpler, immature communitie
habitat fragmentation
breakup of a habitat into smaller pieces, usually as a result of human activities
ecotones
a region of transition between two biological communities
ecozones
ecorealm, biogeographic realm or simply biorealm is the largest scale biogeographic division of Earth's land and is characterized by interactive and adjusting abiotic and biotic factors
edge effect
placing side by side of contrasting environments on an ecosystem
theory of island biogeography
a field within biogeography attempting to explain what factors affect the species richness of natural communities
law of tolerance
the amount of an item that can be present before a permanent helpful/harmful effect will take place
law of minimum
growth is controlled not by the total amount of resources available, but by the scarcest resource or limiting factor
population density
number of organisms in a particular population found in a specified area or volume.
population dispersion
general pattern in which the members of a population are arranged throughout its habitat
r selected organisms
have a high growth rate, suitable in an unstable environment, short lives, and have many offspring
k selected organisms
populations or roughly constant size, low productive rates, limited and competitive in resources
disease, hunting, natural factors
3 population limiting factors
education, cultural influence, government policies
3 factors affecting fertility rates
replacement birth rate
total fertility rate at which women would have only enough children to replace themselves and their partner
better medical attention, new technology, better hygiene
3 reasons people live longer