Upper layer of a body of water through which sunlight can penetrate and support photosynthesis.
Gross Primary Production, rate at which an ecosystem's producers convert solar energy into chemical energy
rate at which producers use photosynthesis to store enregy minus the energy they use for aerobic respiration
Liebig's Law of the Minimum
too little of something effects growth; growth is not controlled by the total resources available, but by the scarcest resource, limiting factor
Shelford's Law of Tolerance
the presence and success of an organism depend upon the extent to which a complex of conditions is satisfied
Process in which various chemicals in upper layers of soil are dissolved and carried to lower layers and, in some cases, to groundwater.
Plants that live on the surface of other plants without doing harm
process by which two species evolve in response to changes in each other
zone of physiological stress
the range of enviromental conditions where an organism is not comfortable; its body is not workng at its optimal
The range of environmental conditions over which an organism performs best and can reproduce.
optimal foraging theory
the basis for analyzing behavior as a compromise of feeding costs versus feeding benefits
the relation between two different kinds of organisms when one receives benefits from the other without damaging it
a species that influences the survival of many other species in an ecosystem
the extinction of a species from specific geographic areas
in a biological community various populations sharing environmental resources through specialization thereby reducing direct competition
an ecological succession that begins in a an area where no biotic community previously existed
succession following a disturbance that destroys a community without destroying the soil
a stable, mature community that undergoes little or no change in species over time
the final, equilibrium vegetation for a site that is dictated by climate and which all successions proceed
A climax where topography or soil exert sufficient influence to produce a self-perpetuation, steady-state vegetation distinct from the climatic climax
process by which a body of water becomes too rich in dissolved nutrients, leading to plant growth that depletes oxygen
Interrupted succession where interference halts the process of succession so that the climax community is not reached; often a result of human activities
biochemicals produced by one species that alter growth, dev. of others
water nessesary for ships can introduce harmful species of invasive ones to new enviroments
Species that reproduce early in their life span and produce large numbers of usually small and short-lived offspring in a short period.
Species that produce a few, often fairly large offspring but invest a great deal of time and energy to ensure that most of those offspring reach reproductive age. Compare r-selected species.
the tendency of an object to resist any change
the tendency to recover from any change
species that do not naturally occur within an area and that have usually arrived in the area as a result of human intervention (whether deliberate or accidental)
plants and animals that have migrated to areas where they did not originate; often displace native species by outcompeting them for resources
biological nitrogen fixation
Microbial conversion of dinitrogen gas (N2) in atmosphere to N-containing organic compounds
feedback in phase with (augmenting) the input
A primary mechanism of homeostasis, whereby a change in a physiological variable triggers a response that counteracts the initial change.
the working together of two things (muscles or drugs for example) to produce an effect greater than the sum of their individual effects
largest number of individuals of a population that a environment can support
maximum rate at which a population could increase under ideal conditions
process by which certain bacteria convert nitrogen gas to ammonia
process in which fixed nitrogen compounds are converted back into nitrogen gas and returned to the atmosphere
Low nutrient, clear water that supports small populations of aquatic organisms
-Good light penetration
-Deep waters and low algal growth
The sudden runoff of large amounts of highly acidic water into lakes and streams when snow melts in the spring or when heavy rains follow a drought