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| Ecology
Definitions |
Based on: A Dictionary of Ecology, Evolution and
Systematics by R.J. Lincoln , G.A. Boxshall and P.F. Clark, Cambridge
University Press, 1982; and The Harper Collins Dictionary of Biology
by W.G. Hale and J.P. Margham, Harper Perennial, 1991.
Abiotic Non-living
Acclimation
The change in behavior or physiology of an individual within its own
lifetime in response to a changing environment.
Adaptation
Change in organisms over many generations through inheritance of modified
genes, resulting in improved survival and reproduction.
Amphipod
Order of crustaceans including shrimp. Freshwater amphipods look like
miniature shrimp.
Antagonism
The inhibiting action of one substance or organism on another.
Aquatic
Living in or near water.
Arthropod Animals
having jointed limbs and a hard exoskeleton. Includes insects, crustaceans,
spiders and centipedes.
Autotroph
An organism capable of producing its own food without having to eat
other organisms.
Biodiversity
The number of different species within a given geographical region.
Biomass
Quantitative measure of the total mass of organisms comprising all
or part of a population or any other specified unit such as an individual,
plot of ground, set of plants, etc. Measured as volume, mass, or weight
of dead, dry, or live organisms.
Biome Major regional
ecological community characterized by distinctive life forms, climate
and principal plant (terrestrial) or animal (marine) species.
Biotic Pertaining
to life or living organisms.
Biotic potential
The highest level of physical development and reproduction
attainable by an organism, when all conditions are perfect.
Carnivore Organism
that eats the flesh of another animal, including insects.
Chloroplast
Structure within the internal cells of leaves containing chlorophyll.
Photosynthesis occurs in chloroplasts.
Chlorophyll
Pigment in chloroplasts of plants where photosynthesis occurs. Chlorophyll
is green, thus giving plants their color.
Community Any
group of organisms belonging to a number of different species that
occur together in the same habitat or area and interact through trophic
and spatial relationships.
Competition
The simultaneous demand by two or more organisms or species for a
common resource that is actually or potentially in limited supply
(exploitation competition), or the negative interaction between two
or more organisms or species for a common resource that is not limiting
(interference competition).
Consumer An organism
that feeds on another organism or on existing organic matter, consumers
include herbivores, omnivores, carnivores, and parasites.
Crepuscular
Active during dawn and dusk only.
Crustacean Class
in the phylum Arthropoda. Includes lobsters, pill bugs, shrimp.
Cuticle A non-cellular
layer on the surface of plant tissues which prevents or retards water
loss. Cuticle does not cover stomata.
Decomposer Organism
that breaks organic matter down into its simpler compounds and eventually
into inorganic matter, which is then used by producers (plants). Decomposers
are bacteria and fungi.
Desiccation
The drying process; moisture removed from an organism.
Density The number
of things within a given area or volume.
Detritivore
Small organisms (bacteria, fungi, worms) that feed on small pieces
of dead plants and animals. Part of the nutrient cycle.
Diurnal Active during
the daylight hours.
Diversity The
absolute number of species in a community or sample regardless of
the number of individual organisms.
Drought Evasion
Refers to plants sensitive to drought that can survive dry periods
by the production of desiccation resistant seeds or structures.
Drought Resistance
The capacity to withstand periods of dryness, including both desiccation
avoidance and tolerance.
Ecology The study
of the interrelationships between living organisms and their environment.
Ecosystem A community
of organisms and their physical environment interacting as a unit.
Ectotherm An animal
whose body temperature is determined by that of the surrounding environment,
but is not necessarily exactly the same as the environmental temperature.
All animals except mammals and birds are ectotherms.
Emigration The
movement of an individual or group out of an area or population.
Endemic
Organism that evolved in a given ecosystem. (See native)
Endotherm Animal
who maintains a core body temperature regardless of the temperature
of the surrounding environment. Mammals and birds are endotherms.
Endoskeleton
Skeleton present internally.
Energy Fixation
The process by which an organism captures energy by consuming
food. Usually a maximum of 10% of the total energy available is captured
and used by the organism for growth and maintenance; the rest is lost
back to the environment as free heat.
Energy flow
The movement of energy through an ecosystem from the sun (photons)
to producers (plants), to primary consumers (herbivores) to secondary
consumers (predators). Most energy is lost back into the environment
at each transition level.
Ephemeral Lasting
briefly, such as mayfly adults who live only a few hours, or plants
that live less than a year.
Evaporation
The change of water to a gas. Used by animals for cooling. In plants
it is called transpiration.
Evapotranspiration
Total evaporation of water in an area from plants and the surrounding
ground.
Evolution The
change over generations in a species due to inherited genetic modifications.
Exoskeleton
Skeleton present on the outside of the body.
Exotic An imported,
non-native organism, brought into an ecosystem it did not inhabit
before.
Fitness The success
of an organism in passing its genes on to the next generation through
its offspring. High fitness is having many offspring, low fitness
refers to few or no offspring.
Food Chain A
sequence of organisms on successive trophic levels within a community,
through which energy is transferred by feeding; energy enters the
food chain during fixation by primary producers (mainly green plants)
and passes to the herbivores (primary consumers) and then to the carnivores
(secondary and tertiary consumers).
Food Web The network
of interconnected food chains of a community; food cycle.
Gall Accelerated tissue
growth on a plant caused by insects, mites or fungi. Insect caused
galls usually indicate an area of the plant where eggs were laid inside
the tissue.
Herbivore Organism
that feeds on plants.
Herbivory The consumption of plant material by an animal
Heterotroph
An organism that does not produce its own food but obtains nutrients
from external organic sources: herbivores, carnivores.
Homeostasis
The maintenance of a steady state or equilibrium in a biological system
by internal regulating mechanisms.
Host The organism a
parasite lives on.
Immigration
The movement of an individual or group into a new population or geographical
region.
Inorganic
Refers to compounds from non-living sources such as rocks and water.
Non-biological compounds, specifically, those not containing carbon
atoms.
Interspecific
Interactions occurring between two or more different species.
Intraspecific
Interactions occurring within a species; between individuals or populations
of the same species.
Isopod
Scientific name for pill bugs, sow bugs, or rollie-pollies. Crustacean.
Iteroparity
Several or many reproductive periods in a lifetime.
Larva (pl. larvae)
The immature stage of life of an invertebrate.
Life History
The significant features of the life cycle through which an
organism passes, with particular emphasis on aspects and strategies
affecting survival and reproduction.
Limiting factor
Any environmental factor, or group of related
factors, that exists at a lower than necessary level and thereby prevents
an organism from reaching its full biotic potential.
Macroscopic
Of a size the human eye can see easily.
Mesophyll Internal
cells of plant leaves. The exact arrangement of cells varies with
different leaf types. Chloroplasts are contained here.
Microclimate
The climate of the immediate surroundings or habitat resulting from
the local topography, vegetation and soil.
Microhabitat
A small, specialized habitat, such as one part of a tree.
Microscopic
Smaller than the human eye can see.
Migration Movement
of an organism or group from one habitat to another; periodic or seasonal
movement, typically of relatively long distance, from one area, stratum
or climate to another; any general movement that affects the range
of distribution of a population or individual.
Mine Leaf tissue under
the cuticle consumed by an insect. The missing tissue is seen on the
surface of the leaf as a tan area.
Morphology The
body shape of an organism.
Native
Organism that evolved in the given geographical region of study. (See
endemic)
Niche The ecological
role of a species in a community as determined by chemical, spatial,
physical and temporal conditions necessary for that species’
survival. One species occupies a given niche in a given habitat. A
different species may occupy the same niche in a different habitat.
Nocturnal Active
during dark hours.
Non-native An
organism that has been brought into an ecosystem from another ecosystem.
Non-native organisms often have negative effects on the native organisms.
(See exotic.)
Nutrients Material
that an organism takes in and assimilates for growth and maintenance.
Nutrient cycle
The cycle of organic and inorganic matter through an ecosystem, from
producers (plants) to consumers (herbivores and predators) to detritivores
(some insects, worms) to decomposers (bacteria and fungi) back to
producers.
Omnivore Organism
that feeds on a mixed diet of plant and animal material.
Organic
Refers to compounds from previously living organisms; biological compounds,
specifically, those containing carbon molecules.
Parasite
Any organism that is intimately associated with, and metabolically
dependent upon, another living organism (the host) for completion
of its life cycle, and which is detrimental to the host to some greater
or lesser degree.
Parasitoid Insects
whose eggs are laid on a host insect. The larvae grow on or within
the body of the host, eventually killing it.
Photosynthesis
The chemical process used by plants to convert carbon dioxide and
water into organic materials using light energy. Oxygen is released
as a byproduct.
Phytoplankton
Photosynthetic organisms drifting on the surface layer of a sea or
lake.
Pollen The small,
male structure of flowering plants containing the sperm used to fertilize
the female ovules of the same plant species.
Pollination
The fertilization of a flowering plant’s ovules (eggs) by compatible
pollen.
Pollinator Animal
that visits flowers and in the process unintentionally spreads pollen
to other flowers, often fertilizing the eggs of other flowers.
Population All
individuals of one species inhabiting a given geographic area, and
usually isolated to some degree from other groups of the same species.
Predation
The capture, killing, and consumption of one animal (the prey) by
another animal (the predator).
Preferences
A choice an organism makes in regard to mates, food selection, territory,
or other ecological needs.
Producer
(Photosynthesizer/Autotroph)
An organism that synthesizes complex organic substances from energy
and simple inorganic compounds.
Primary
producers on land are plants, in water they are phytoplankton.
Pupa An inactive phase
for many insects between the larval and adult stages. Feeding and
movement are absent while extensive developmental changes occur.
Reducers Any organism
responsible for degrading or mineralizing organic matter from more
complex to less complex compounds; decomposer.
Resource Any biotic
or abiotic component of the environment that can be utilized by an
organism.
Resource
allocation How an organism uses the
resources that it has available for growth, development and reproduction.
Resource Acquisition
The gathering of things needed for survival and reproduction, e.g.,
food, water, light, shelter, mates.
Scavenger An organism
that consumes animal matter left uneaten by a predator. Scavengers
eat carrion, refuse.
Seed Bank
Seeds that accumulate in the soil over a period of years. Seeds
of different ages may germinate in the same year when conditions are
favorable. Many desert wildflowers germinate from seed banks.
Seed Dispersal
Mechanisms by which plant seeds are moved from the parent plant.
Examples of dispersal mechanisms: wind, water, eaten and then excreted,
carried on the bodies of animals.
Semelparity
Single, distinct period of reproductive output in an organism’s
lifetime, after which it usually dies.
Sessile Organism,
plant or animal, that attaches itself to one place and does not move;
e.g., plants and barnacles.
Species A set of
organisms that through physical characteristics and/or behaviors can
only interbreed and produce reproductively viable offspring with each
other.
Species Richness A measure of the absolute number of species in a given habitat or community.
Stoma Openings in
leaf surfaces which allow the entrance of carbon dioxide and the release
of oxygen. Stomata are sometimes found on stems, too.
Substrate Material
used by an organism to grow; solid object to which a plant or sessile
animal is attached.
Succession The
geological, ecological or seasonal sequence of species within a habitat
or community.
Succulence Specialized
fleshy tissue in a plant root or stem for the conservation of water.
E.g., agave.
Symbiosis When
two organisms coexist in a completely dependent and mutually beneficial
manner.
Synergism Cooperative
action of two or more entities such that the total is greater than
the sum of the individual actions.
Temporal Referring
to occurrences in time.
Terrestrial
Occurring on land.
Transpiration
Water that is lost from a plant to the atmosphere through the stomata.
Believed to be part of the mechanism causing water to travel from
the roots up the plant.
Trophic Level
Trophic means nourishment, and trophic level refers to the
position of an organism in a food chain. E.g., primary producer, primary
or secondary consumer.
Zooplankton
Very small animals that float near the surface of a body of water.
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