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Module 16 in the Syllabus

Ecology Images
Image gallery for study with links to larger teaching JPEGs for classroom presentation

Question Drill for Ecology
Conceptual Vocabulary Self-Test

Basic Terms Crossword Puzzle

Basic Puzzle Solution

Conceptual Vocabulary
EcologyEcology is the scientific study of systems of living organisms and the interactions among organisms and between the organisms and their environment.
Earth's atmosphereEarth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity.
EcosystemAn ecosystem is a natural unit consisting of all plants, animals and micro-organisms in an area functioning together with all the non-living physical factors of the environment.
HabitatHabitat is the area where a particular species lives.
BiosphereThe term biosphere was coined by geologist Eduard Suess in 1875, which he defined as the place on earth's surface where life dwells.
BiomassIn ecology, biomass refers to the cumulation of life that is possibly living matter. That is, it is the total living biologica, usually measured per square metre or square kilometre.
BiomeA biome is a major geographical area of ecologically similar communities of plants, animals, and soil organisms, often referred to as ecosystems. Biomes are defined based on factors such as plant structures, leaf types, and other factors like climate.
TundraTundra is an area where the tree growth is hindered by low temperatures and short growing seasons.
PermafrostPermafrost soil is soil at or below the freezing point of water for two or more years.
TaigaTaiga is a biome characterized by coniferous forests. It is the world's largest terrestrial biome.
Food chainFood chains, food webs and/or food networks describe the feeding relationships between species in an ecological community.
Primary productionPrimary production is the production of organic compounds from atmospheric or aquatic carbon dioxide, principally through the process of photosynthesis, with chemosynthesis being much less important.
Ecological nicheA niche is a term describing the relational position of a species or population in its ecosystem, describing how an organism or population responds to the distribution of resources and competitors
HeterotrophA heterotroph is an organism that requires organic substrates to get its carbon for growth and development.
AutotrophAn autotroph is an organism that produces complex organic compounds from simple inorganic molecules and an external source of energy, such as light or chemical reactions of inorganic compounds.
Ecological successionEcological succession refers to more-or-less predictable and orderly changes in the composition or structure of an ecological community.
Primary successionPrimary succession is a type of ecological succession of plant life which occurs in an environment in which new substrate, devoid of vegetation and usually lacking soil, is deposited
Pioneer speciesA pioneer species is a species which colonizes previously uncolonized land, usually leading to ecological succession.
BiodiversityBiodiversity is the variation of life forms within a given ecosystem, biome or for the entire Earth.
Secondary successionSecondary succession is the type of ecological succession of plant life started by an event such as a forest fire or hurricane that reduces an already established ecosystem.
Continental shelfThe continental shelf is the extended perimeter of each continent and associated coastal plain, which is covered during interglacial periods such as the current epoch by relatively shallow seas and gulfs
Intertidal zoneThe intertidal zone, also known as the littoral zone, in marine aquatic environments is the area of the foreshore and seabed that is exposed to the air at low tide and submerged at high tide.
Kelp forestsRecognized as one of the most productive and dynamic ecosystems on Earth, kelp forests are formed by brown macroalgae of the order Laminariales.
Carbon cycleThe carbon cycle is the biogeochemical circuit by which carbon is exchanged between the biosphere, geosphere, hydrosphere, and atmosphere of the Earth.
DecomposerDecomposers, or saprotrophs, are organisms that consume dead organisms, carrying out the natural process of decomposition.
CommunityA community is an assemblage of populations of different species, interacting with one another.
Climax vegetationClimax vegetation is the vegetation which establishes itself on a given site for given climatic conditions in the absence of anthropic action after a long time.
Species richnessSpecies richness is the simplest measure of biodiversity and is simply a count of the number of different species in a given area.
Carrying capacityThe equilibrium maximum of the population of an organism is known as the ecosystem's carrying capacity for that organism.
K-strategistsK-strategists are organisms that grow slowly and usually require parenting until maturity, such as whales.
Abiotic componentsAbiotic components are non-living chemical and physical factors in the environment.
EcozoneAn ecozone or biogeographic realm is the largest scale biogeographic division of the earth's surface based on the historic and evolutionary distribution patterns of plants and animals.
EcoregionAn ecoregion, sometimes called a bioregion, is the next smallest ecologically and geographically defined area beneath realm or ecozone.
Benthic zoneThe benthic zone is the lowest level of a body of water such as an ocean or a lake.
Biogeochemical cycleA biogeochemical cycle is a circuit or pathway by which a chemical element or molecule moves through both biotic and abiotic compartments of an ecosystem.
Foundation speciesA foundation species is a dominant primary producer in an ecosystem both in terms of abundance and influence.
Ecological pyramidAn ecological or trophic pyramid is a graphical representation designed to show the biomass or productivity at each trophic level in a given ecosystem.
Community ecologyCommunity ecology is a subdiscipline of ecology which studies the distribution, abundance, demography, and interactions between coexisting populations.
Competitive exclusion principleThe competitive exclusion principle is a theory which states that two species competing for the same resources cannot stably coexist.
InsolationInsolation is a measure of solar energy received on a given surface area in a given time. Within ecology, it is commonly expressed in kilowatt-hours per square meter per day.
BiotaBiota is the total collection of organisms of a geographic region or a time period, from local geographic scales and instantaneous temporal scales all the way up to whole-planet and whole-timescale spatiotemporal scales.
BiotopeA biotope is an area of uniform environmental conditions providing a living place for a specific biological community of plants and animals.
Photic zoneThe photic or euphotic zone is the depth of the water, whether in a lake or an ocean, that is exposed to sufficient sunlight for photosynthesis to occur.
ThermoclineThe thermocline, sometimes called a metalimnion, is a layer within a body of water or air where the temperature changes rapidly with depth.
Lentic system ecologyLentic system ecology is the study of the biotic and abiotic interactions within still continental waters.
EthologyEthology is the scientific study of animal behavior, and a branch of zoology.
Fixed action patternA fixed action pattern is an instinctive behavioral sequence that is indivisible and runs to completion.
MicroclimateA microclimate is a local atmospheric zone where the climate differs from the surrounding area.
Eugenius WarmingEugenius Warming (1841 - 1924) was a Danish botanist and a main founding figure of the scientific discipline of ecology.
LithosphereThe lithosphere is the solid outermost shell of a rocky planet. On the Earth, the lithosphere includes the crust and the uppermost mantle.
HydrosphereA hydrosphere in physical geography describes the collective mass of water found on, under, and over the surface of a planet.
HydrosereA hydrosere is a plant succession which occurs in a freshwater lake.
Advanced terms that may appear in context in MCAT passages
Pelagic zoneThe pelagic zone is the part of the open sea or ocean that is not near the coast.
Neritic zoneThe neritic zone spans from the low-tide line to the edge of the continental shelf in oceans.
Fitness landscapeFitness landscapes or adaptive landscapes are used to visualize the relationship between genotypes, or phenotypes, and reproductive success.
Nitrate reductaseNitrate reductase enzymes are a group of enzymes which reduce nitrate to nitrite.
Trophic dynamicsTrophic dynamics is the system that describes the position that an organism occupies in a food chain - what it eats and what eats it.
Trophic cascadeTrophic cascades occur when predators in a food chain suppress the abundance of their prey, thereby releasing the next lower trophic level from predation.
Lotic system ecologyLotic system ecology is the study of the biotic and abiotic interactions within flowing continental waters.
LithosereA lithosere is a plant succession that begins life on a newly exposed rock surface, such as one left bare as a result of glacial retreat, tectonic uplift as in the formation of a raised beach, or volcanic eruptions.
Seral communityA seral community is an intermediate stage found in ecological succession in an ecosystem advancing towards its climax community.
EutrophicationEutrophication means an increase in chemical nutrients, typically compounds containing nitrogen or phosphorus, in an ecosystem.
GeophysiologyGeophysiology is the study of interaction among living organisms on the Earth operating under the hypothesis that the Earth itself acts as a single living organism (Gaia).
Charles Sutherland EltonCharles Sutherland Elton (1900 - 1991) was an English biologist credited with establishing modern population ecology.
Autogenic successionAn autogenic succession describes a succession where the stimulus for change is an internal one.
Allogenic successionAn allogenic succession describes a succession where the stimulus for change is an external one.
HNLCHNLC is a term used in marine ecology to describe areas of the ocean where the number of phytoplankton are low in spite of high macro-nutrient concentrations.
Lotka-Volterra equationThe Lotka-Volterra equations, also known as the predator-prey equations, are a pair of first order, non-linear, differential equations frequently used to describe the dynamics of two species interactions, one a predator and one its prey.

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