Ecology Test 4 vocab

  The evolution of two interacting species, each in response to selection pressure imposed by the other.

A parasite that lives on the surface of another organism. Compare endoparasite.

A parasite that lives inside the body of its host organism. Compare ectoparasite.

A specific defensive response that makes particular plant genotypes resistant to particular parasite genotypes.

An organism on or within which a parasite or other symbiont lives.

Relatively large parasite species, such as arthropods and worms. Compare microparasites.

Parasite species too small to be seen with the naked eye, such as bacteria, protists, and fungi. Compare macroparasites.

An organism that lives in or on a host organism and feeds on its tissues or body fluids.

A parasite that causes disease.

An organism that lives in or on an organism of another species, referred to as its host; a symbiont is the smaller member of a symbiosis. See also host, symbiosis.

The minimum number of individuals susceptible to a disease that must be present in a population for the disease to become established and spread.

Mycorrhizae in which the fungal partner grows into the soil, extending some distance away from the plant root, and also grows between some root cells while penetrating others. Compare ectomycorrhizae

In a mutualism, an individual that increases its production of offspring by overexploiting its mutualistic partner.

An interaction between two species in which individuals of one species benefit while individuals of the other species do not benefit and are not harmed.

Mycorrhizae in which the fungal partner typically grows between plant root cells and forms a mantle around the exterior of the root. Compare arbuscular mycorrhizae.

A mutualism in which one partner provides the other with shelter, a place to live, or favorable habitat.

A mutually beneficial interaction between individuals of two species (a +/+ relationship).

Symbiotic associations between plant roots and various types of fungi that are usually mutualistic.

Interactions between species in which one or both species benefit and neither is harmed.

A mutualism in which one partner performs an ecological service for the other.

A relationship in which two species live in close physiological contact with each other. See also host, symbiont.

A mutualism in which one or both of the mutualists receives energy or nutrients from its partner.

The diversity of important ecological entities that span multiple spatial scales, from genes to species to communities.

The set of characteristics that shape a community, including the number, composition, and abundance of species.

A group of interacting species that occur together at the same place and time.

Sets of competitive interactions involving multiple species in which every species negatively interacts with every other species thus promoting species coexistence.

Interactions between two species, including competition, exploitation, and positive interactions. Compare indirect interactions.

A species that has large, community-wide effects by virtue of its size or abundance, its strong competitive ability, or its provision of habitat or food for other species, also called a foundation species.

A species that influences its community by creating, modifying, or maintaining physical habitat for itself and other species.

  See dominant species.

A subset of a community that includes species that function in similar ways, but do not necessarily use the same resources. Compare guild.

A subset of a community that includes species that use the same resources, whether or not they are taxonomically related. Compare functional group.

Non-trophic interactions, such as competition and some positive interactions, that occur within a trophic level.

Interactions in which the relationship between two species is mediated by a third (or more) species. Compare direct interactions.

A measure of the effect of one species (the interactor) on the abundance of another species (the target species).

A concept that describes both the trophic (vertical) and non-trophic (horizontal) interactions among the species in a traditional food web.

A strong interactor that has an effect on energy flow and community structure that is disproportionate to its abundance or biomass.

(1) In trophic studies, an organism that feeds on more than one trophic level. (2) An organism that feeds on both plants and animals."

A graph that plots the proportional abundance of each species in a community relative to the others in rank order, from most abundant to least abundant.

The index most commonly used to describe species diversity quantitatively.

A graph that plots species richness as a function of the total number of individuals that have accumulated with each additional sample.

The identity of the species present in a community.

A measure that combines the number of species (species richness) in a community and their relative abundances compared with one another (species evenness).

The relative abundances of species in a community compared with one another.

The number of species in a community.

A change in the rate of consumption at one trophic level that results in a series of changes in species abundance or composition at lower trophic levels.

An interaction in which a consumer is indirectly facilitated by a positive interaction between its prey or food plant and another species.

A group of species that obtain energy in similar ways, classified by the number of feeding steps by which the group is removed from primary producers, which are the first trophic level.

Species diversity at the local or community scale. Compare beta diversity, gamma diversity.

The change in species number and composition, or turnover of species, as one moves from one community to another. Compare alpha diversity, gamma diversity.

A portion of Earth containing a distinct biota that differs markedly from the biotas of other biogeographic regions in its species composition and diversity.

The study of variation in species composition and diversity among geographic locations.

The slow movement of tectonic plates (sections of Earth's crust) across Earth's surface.

Occurring in a particular geographic location and nowhere else on Earth.

A theory proposing that the number of species on an island or in an island-like habitat results from a dynamic balance between immigration rates and extinction rates.

Species diversity at the regional scale; the regional species pool. Compare alpha diversity, beta diversity.

A spatial scale that is essentially equivalent to a community.

A spatial scale that encompasses a geographic area where the climate is roughly uniform and the species contained therein are often restricted to that region by dispersal limitation.

All the species contained within a region; sometimes called gamma diversity.

The relationship between species richness and area sampled.

(1) The mixing of the entire water column in a stratified lake when all the layers of water reach the same temperature and density. (2) The replacement of one species with another over time or space.

The evolutionary separation of species due to a barrier such as continental drift that result in the geographic isolation of species that once were connected to one another.

A liquid or gas fuel made from plant material (biomass).

Interactions of the native species in a community with non-native species that exclude or slow the growth of those non-native species.

Of or relating to fuels that produce an amount of CO2 when burned that is equal to or less than the amount taken up by the plants from which they are made.

A hypothesis proposing that as the species richness of a community increases, there is a linear increase in the positive effects of those species on community function. Compare redundancy hypothesis.

A hypothesis proposing that the strengths of the effects of species' ecological functions on their communities vary dramatically, such that "driver" species have a large effect on community function, while "passenger" species have a minimal effect.

An elaboration of the intermediate disturbance hypothesis proposing that species diversity is maximized when the level of disturbance and the rate of competitive displacement are roughly equivalent.

A hypothesis proposing that species diversity in communities should be greatest at intermediate levels of disturbance (or stress or predation) because competitive exclusion at low levels of disturbance and mortality at high levels of disturbance should reduce species diversity.

A hypothesis proposing that species diversity in communities is maintained by a "lottery" in which resources made available by the effects of disturbance, stress, or predation are captured at random by recruits from a larger pool of potential colonists.

A hypothesis that assumes an upper limit on the positive effect of species richness on community function because once species richness reaches some threshold, the functions of species in the community will overlap. Compare complimentary hypothesis.

(1) Any force that impedes the movement of compounds such as water or CO2 across an energy or concentration gradient; its opposite is conductance. (2) The ability of a community to resist change from outside influences such as disturbance.

The use of limiting resources by different species in a community in different ways.

A hypothesis proposing that species can coexist in a community by using the same resources, but in differing proportions.

The tendency of a community to remain the same in structure and function.