UNIT VOCABULARY & NOTES Stability and Change

Ecological succession (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

Biomass Organic matter produced by plants and other photosynthetic producers; total dry weight of all living organisms that can be supported at each trophic level in a food chain or web; dry weight of all organic matter in plants and animals in an ecosystem; plant materials and animal wastes used as fuel.

Population Group of individual organisms of the same species living in a particular area.

Biotic Potential (reproductive potential) Maximum rate at which the population of a given species can increase when there are no limits on its rate of growth.

Exponential growth Growth in which some quantity, such as population size or economic output, increases at a constant rate per unit of time. When the increase in quantity over time is plotted, this type of growth yields a “J” shaped curve.

Carrying capacity Maximum population of a particular species that a given habitat can support over a given period.

Symbiosis The relationship between two different species of organisms that are interdependent; there are various types of symbiotic relationships

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.

Mutualism Type of species interaction in which both participating species generally benefit.

Commensalism An 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.

Competition Two types:  intraspecific competition-two or more individual organisms of a single species attempting to use the same scarce resources in the same ecosystem  interspecific competition- two or more individuals of different species attempting to use the same scarce resources in the same ecosystem

Predation Situation in which an organism of one species (the predator) captures and feeds on parts or all of an organism of another species (the prey).

Ecological niche (niche) Total way of life or role of a species in an ecosystem. It includes all physical, chemical, and biological conditions that a species needs to live and reproduce in an ecosystem.

Ecological diversity The variety of forests, deserts, grasslands, oceans, streams, lakes, and other biological communities interacting with one another and with their nonliving environment.

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.

Growth rate The rate, or speed, at which the number of organisms in a population increases.