ENVS 200 - Final Exam (Key Terms)

Metapopulations

Isolated populations that are connected by immigration and emigration

Disturbance

Temporary change in environmental conditions that causes a pronounced changed in an ecosystem

Primary Succession

Sequence of ecosystem development without influence from prior community

Secondary Succession

Sequence of ecosystem development with influence from prior community

Climax

Final stage of succession that is thought to be self-replacing and stable

Food Web

What-eats-what in an ecological community

Trophic Cascades

Predators suppress the abundance or alter the behaviour of their prey, releasing the next trophic level from predation

Gap

Inadequate ecological conditions caused by disturbances

Founder-Controlled Community

Communities where all species are good colonists and essentially equal competitors Prio

Priority Effect

Species that arrive first at a site are able to hold it against competing invaders, whatever the outcome would be if they competed as simultaneously arriving equals

Dominance-Controlled Community

Communities where some species are strongly superior competitively

Community Succession

Early species are good colonizers and fast growers whereas later species can tolerate lower resource levels and grow to maturity, eventually outcompeting the early species

Chronosequence

Series of communities currently in existence; Can be used to infer what the succession must have been

Trophic Level

Position that an organism occupies in the food web Su

Super Predator

Humans

Top-Down Control (Predator Controlled)

Populations of organisms in lower trophic levels are controlled by organisms at the top

Bottom-Up Control

Driven by the presence or absence of the producers in the ecosystem

Meta-Analysis

Structured analyses of large numbers of data sets wtiha. view to discerning consistent trends

Biological Diversity

Variability among living organisms from all sources (includes diversity within species, between species, and of ecosystems)

Biodiversity

Degree of variation in life

Species Richness

Refers to the no. of unique species

Species Eveness

Amount of each species in a communtiy and how evenly the species are distributed

Hot Spots

Localiteis known to support a large number of species of a specific favoured group Ec

Ecoregions

Broad-brush areas delineated by geogaphy and vegetation

Diversity Index

Measures that combine species richness and the evenness of the equitability of the distribution of individuals among those species

Evenness

Distribution of abundance across species in a community

Niche Breadth

Diversity of resources used or environments tolerated by an individual/species

Niche Overlap

Situation in which co occurring species share parts of their niche space with each other

Productivity Hypothesis

Emphasizes the importance of climate in determining productivity at the lowest trophic level

Energy Hypothesis

Emphasizes the direct role of energy on organisms throughout the community

Eutrophication

Conditions that occur when environment becomes enriched with nutrients, increasing amount of plant growth in waters

Particulate Organic Matter

Rain of chemical energy falling as dead organic matter from the sea surface

Alpha Diversity

Diversity at a local scale

Beta Diversity

Differences among communities within a region

Upsilon Diversity

Diversity at the whole regional scale; Alpha + Beta diversity

Potential Evapotranspiration

Amount of water that would evaporate or be transpired from a staured surface and hence, a measure of atmospheric energy

Net Primary Productivity

Amount of carbon retained in an ecosystem

Benthic

Anything associated with or occuring on the bottom of a body of water

Predictable Variation

Variation that occurs on a time scale similar to the generation time of the species in a community themselves

Unpredictable Changes

Most naturally viewed as disturbances to a community that changes its composition

Intermediate Disturbance Hypothesis

Communities are expected to contain most species when the frequency of disturbance is neither too high or too low

1st Law of Thermodynamics

Conservation of mass or energy

2nd Law of Thermodynamics

In an isolated system, entropy never decreases

Entrophy

Unavailability of a systems energy to do mechanical work

Trophic Transfer Efficiency

= CE x AE x PE

Immobilization

Inorganic nutrient element is changed into an organic form

Mineralization

Conversion of elements from organic form to inorganic form

Decomposition

Gradual disintegration of dead organic matter by both physical and biological agents

Standing Crop

Bodies of living organisms within a unit area constitute a standing crop of biomass

Biomass

Mass of organisms per unit area of ground or water, usually expressed in units of energy

Primary Productivity

Rate at which biomass is produced per unit area or volume through photosynthesisG

Gross Primary Productivity (GPP)

Total fixation of energy by photosynthesis

Net Primary Productivity (NPP)

Difference between GPP and energy lost as respiratory heat; Represents actual rate of production of new biomass available for consumption

Secondary Productivity

Rate of production of biomass by heterotrophs

Net Ecosystem Productivity (NEP)

Difference between GPP and respiration of all organisms in an ecosystem

Live Consumer System

Proportion of primary production is consumed by herbivores which are then consumed by carnivores

Decomposer System

Fraction of NPP that is not eaten by herbivores passes through this system

Detritus

Dead organic matter

Decomposer

Organisms which decompose detritus

Detrivore

Animals that consume detritus

Leibig's Law of the Minimum

Fact that one particular element (usually either N or P), can limit productivity

Colimitation

Phenomenon where in some ecosystems, both N and P are limiting to production

Transfer Efficiences

Proportions of net primary production flowing along each of the possible energy pathways depend on these

Consumption Efficiency

Percentage of total productivity available at one trophic level that is consumed by the trophic level above

Assimilation Efficiency

Percent of food energy taken into consumers in a trophic level that is assimilated across the gut wall and becomes available for incorporation into growth or to do work

Productive Efficiency

Percentage of assimilated energy incorporated into new biomass

Biogeochemistry

Science that addresses the biotic controls on chemistry of the environment and the geochemical control of the structure and function of ecosystems

Source Sink

Refers to sites of such storage of an element

Radiative Forcing

Imbalance between incoming solar radiation and outgoing infrared radiation that results in global warming

Residence Time

Expresses how fast something moves through a system in equilibrium

Methanogenesis

Production of methane by bacteria in the absence of oxygen

Conservation

Collective name given to various actions we can take to slow down or reverse losses of species and biodiversity

Critically Endangered

Considered to be more than 50% probability of extinction in 10 years or three generations

Endangered

If there is more than 20% chance of extinction in 20 years or five generations

Vulnerable

If there is a greater than 10% chance of extinction in 100 years

Near Threatened

If the species is close to qualifying for a threat category

Of Least Concern

Species that do not meet any threat categories De

Homozygous

Identical alleles from mother and father

Inbreeding Depression

Deleterious effects that result from having homozygous alleles

Overexploitation

Populations are harvested at a rate that is unsustainable, given natural rates of mortality and capacities for reproduction

Invasive Species

Organism that is not native to an area

Extinction Vortex

Population may have been reduced to a small size by 1+ processes which leads to increased frequency of mating among relatives and deleterious recessive alleles in offspring, leading to reduced survivorship and fecundity and causing population to further shrink

Lichen

Mutualism of a fungus and an algae

Poikilohydric Organisms

Absorb water from their environment straight through their cortex

Combined Sewer Overflow

Pipe that, during storms, discharges untreated wastewater from a sewer system that carries both sanitary wastewater and stormwater; No longer used

Constraint Planning

Landscape is viewed as having cultural and historic features, and abiotic and biotic features which provide both constraints and opportunities for development.

Groundwater

Created by rain that soaks into the ground and flows until it collects above an impervious zone

Aquifer

Volume of porous rock of unconsolidated deposits that can store ground water

Riparian Zone

Zone of transition from an aquatic to a terrestrial zone

Runoff

The amount of precipitation not absorbed into the ground that flows into surface water bodies or into the storm sewer system

Sanitary Sewer

A sewer used to collect used water from buildings including sewage and grey water

Storm Sewer

A sewer used to collect runoff from streets, roofs and parking lots

Stormceptors

Special manholes along storm sewers that remove oil & pollutants from the water.

Storm Water Management Pond (SWM Pond)

Provides storm water flow control, recharges groundwater, and improves water quality by enhancing removal of pollutants.

Urban Heat Isalnd

Where there are higher temperatures in a built-up environment, for example a city, due to human activity –highly reflective surfaces, automobile exhaust, buildings, etc., when compared to rural areas.

Watershed

All the land and tributaries draining to a body of water.