deck_4243923 Flashcards
1
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species
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a population or group of populations of organisms were member share certain characteristics and can breed freely with one another and produce fertile offspring. different biologists may have different approaches to diagnosing a species boundaries
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population
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a group of organisms of the same species that live in the same area. species are often composed of many species
3
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natural selection
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the process by which traits that enhance survival and reproduction are passed on more frequently to future generations of organisms than traits that do not, thus altering the genetic population through time
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mutation
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an accidental change in DNA that may range in magnitude from the deletion, substitution, or addition of a single nucleotide, to a change effecting entire sets of chromosomes. mutations provide the new material for evolutionary change
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adaptation (evolution)
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the process by which traits that lead to increased reproduction success in a given environment evolve in a population through natural selection
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adaptation (climate change)
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the pursuit of strategies to protect ourselves from the impacts of climate change
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adaptive trait
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a trait that confers greater likelihood that an individual will reproduce. also called an adaptation
8
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convergent evolution
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the evolutionary process by which unrelated species acquire similar characteristics/traits as they adapt to selective pressure from their similar enviroments
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speciation
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a process by which new species are generated
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biodiversity (biological diversity)
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the variety of life across all levels of biological organization, including the diversity of species, their genes, their populations, and their communities
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artificial selection
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natural selection conducted under human direction
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phylogenetic tree
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a tree like diagram that represents the history of divergence of species or other taxonomic groups of organisms
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extinction
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the disappearance of an entire species from earth
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fossil records
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the cumulated body of fossils worldwide, which paleontologists study to infer the history if past life on earth
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endemic
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native or restricted to a certain region. an endemic species occur only in one place in the world
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mass extinction events
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the extinction of a large percentage of the worlds species in a very short period of time, earth has been in 5 mass extinction events in the past half-billion years
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survivorship curve
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a graph that shows the likely-hood of death for members of a population varies with age
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demographer
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a social scientist who studies population size, density, distribution, age structure, sex ratio, and birth, death, immigration, and emigration rates within the human population
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immigration
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the arrial of individuals from outside the population
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emigration
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the departure of individuals from a population
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rate of natural increase
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the rate of change in a population size resulting from birth and death rates alone
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population growth rate
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the rate of change in a population size per unit time. counts death, birth, immigration, and emigration rates (is usually measured in time per year)
23
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limiting factor
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a physical, chemical, or biological characteristic of the environment that restricts the population growth
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carrying capacity
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the maximum population size that a given environment can substain
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logistic growth curve
a plot that shows the initial exponential growth of a population is slowed and finally brought to a stand still by limiting factors
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K-selected
term denoting a species with low biotic potential whose members produce a small number of offspring and take a long time to gestate and raise each of their young, but they invest heavily on the survival and growth of their few offspring
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density-independent factors
a limiting factor whose effects are the same no matter the population size
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density-dependent factors
a limiting factor whose effects on a population increase or decrease depending on the population density
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age structure (age distribution)
the relative number of organisms of each age within a population. age distribution can have a great effect on rates of population growth or decline and are often expressed as a ratio of age classes, consisting of organisms (1) not yet mature enough to reproduce (2) capable of reproduction (3) beyond reproduction years
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sex ratio
the proportion of males to females in population
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population size
the number of individual organisms present at a given time in an organisms population
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specialist
a species that can survive only in a narrow range of habitats that contain very specific recources
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generalist
a species that can survive in a wide variety of habitats or use a wide array of recources
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niche
the functional role of a species in a community
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habitat selection
the process by which organisms select habitats from among the range of optionsencountered
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habitat
the specific environment in which an organism lives, including both biotic and abiotic factors
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ecology
the science that deals with distribution and abundance of organisms, the interactions between them and their abiotic environment
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biosphere
the sum total of all the planets organisms and the abiotic environment with which they inetact
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population ecology
the study of the quantitative dynamics of population change and the functions that affect the distribution and abundance of members of a population
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community
an assemblage of populations of organisms that live in the same place at the same time
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community ecology
the scientific study of the patterns of species diversity and interactions among species, from one to one interactions to complex inter-relationships involving entire communities
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ecotourism
visitation of natural area fro tourism and recreation. most often involves tourism by more affluent people, which may offer economic benefits for less affluent communities near natural areas and thus provide economic incentives for conservation of natural areas
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phytoplankton
microscopic photosynthetic algae, pratists, and cyanobacteria that drift near the surface of water bodies and generally form the first trophic level in an aquatic food chain.
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zooplankton
tiny aquatic animals that feed on phytoplankton and generally make up the second layer of the food chain
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competition
a relationship in which multiple organisms seek the same limited recourse
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intraspecific competition
competition that takes place among members of the same species
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interspecific competition
competition that takes place among members of two or more different species
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fundamental niche
the full niche of a species
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realized niche
the portion of the fundamental niche that is fully realized (used) by a species
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species coexistence
an outcome of intraspecific competition in which no competing species fully excludes the other and the species continue to coexist
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competition exclusion
an outcome of interspecific competition competition in which one species excludes another species from a resource entirely
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character displacement
a phenomenon resulting from competition among species in which competing species evolve characteristics that better adapt them to specifically use the portion of the resource that they use. the species essentially become more different from each other reducing their competition
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resource partitioning
the process by which species adapt to competition by evolving to use slightly different resources, or to use their shared resources in different ways, thus minimizing competition with one another
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predation
the process in which one species (the predator) hunts, tracks, captures, and eventually kills its prey
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predator
an organism that hunts, capture, kills and consumes individuals of another species, the prey
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prey
an organism that is killed and consumed by another species
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paratism
a relationship in which one organism, the parasite, depends on another, the host, for nourishment or some other benefit while simultaneously doing the host harm
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parasite
the organism in a parasitic relation ship that extracts nourishment or some other benefit from the host
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host
the organism in a parasitic relationship that suffers harm while providing the parasite nourishment or some other benefit
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parasitoid
an insect that parasitizes other insects, generally causing eventual death of the host
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pathogens
a parasite that causes disease in its host
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coevolution
the process in which two or more species evolve in response to each other. parasites and hosts may coevolve , as may flowering plants and their pollinators
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herbivory
the consumption of plants by animals
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pollination
a plant-animal interaction in which one organism (for example a bee or hummingbird) transfers pollen (containing male sex cells) from flower to flower, fertilizing ovaries that grow into fruits with seeds
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trophic levels
ranking in the feeding hierarchy of a food chain. organisms that have higher trophic levels consume those at lower trophic levels
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mutualism
a relationship in which all participating organisms benefit from their interactions
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symiosis
a relationship between different species of organisms that live in close physical proximities. people most often use this term to reference mutualistic relationships, but it can be used for both parasitic and mutualistic relationships
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tertiary consumer
an organism that consumes secondary consumers and feeds at the fourth trophic level
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carnivore
an organism that consumes animals
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detritivore
an organism such as a fungus or bacterium, that breaks down leaf litter and other non-living matter into simple constituents that can be taken up and used by plants
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food chain
a linear series of feeding relationships as organisms feed on one another, energy is transferred from lower to higher trophic levels
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food web
a visual representation of feeding interactions within an ecological community that shows an array of relationships between organisms of different trophic levels
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keystone species
a species that has an especially far reaching effect on a community
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trophic cascade
a series of changes in the population sizes of organisms at different trophic levels in a food chain, alluring when predators at higher trophic levels indirectly promote populations of organisms at low trophic levels in check. trophic cascades may be evident when a top predator is eliminated from a system
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disturbance
an event that affects environmental conditions rapidly and drastically, resulting in changes to the community and ecosystem. disturbance can be natural, or it van be caused by humans
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succession
a stereotypical series of changes in the structure of an ecological community through time
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primary succession
a stereotypical series of changes as an ecological community develops overtime, beginning with a lifeless substrate in terrestrial systems, primary succession begins when a piece of rock, sand, or sediment becomes newly exposed to the atmosphere and pioneer species arrive. when soil is lost
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secondary succession
a stereotypical series of changes as an ecological community develops overtime, beginning when some event disrupts or dramatically alters an existing community
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resistance
the ability of an ecological community to remain stable in the presence of a disturbance
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resilience
the ability of an ecological community to change in response to disturbance but later return to its original state.
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pioneer species
a species that arrives earliest, beginning the ecological process of succession in a terrestrial of aquatic community
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phase shift (regime shift)
a fundamental shift in the overall character of an ecological community generally occurring after some extreme disturbance and after which the community may not return to its original state
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no-analog community (novel community)
an ecological community composed of a novel mixture of organisms, with no current analog or historical precedent
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introduced species
species introduced by humans from one place to another (whether intentionally or not), a minority of introduced species become invasive species
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invasive species
a species that spreads widely and rapidly becomes dominant in a community, interfering with the communities normal functions
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climax community
in the traditional view of ecological succession, a community that remains in place with little modification (until a disturbance comes along)
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restoration ecology
the study of the historical conditions of ecological communities as they existed before humans altered them. principles of restoration ecology are applied to the practice of ecological restoration
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ecological restoration
efforts to reverse the effects of human disruption of ecological systems and to restore communities to their conditions before disruption
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biome
a major regional complex of similar plant communities; a large ecological unit defined by its dominant plant type and vegetation structure
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climate diagram (climograph)
a visual representation of a regions average monthly temperature and precipitation
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temperate deciduous forest
a biome consisting of midlatitude forests characterized by broad-leafed trees that lose their leaves each fall and remain dormant during the winter. these forests occur in areas where precipitation is spread relatively evenly throughout the year; much of Europe, eastern china, and eastern north america
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temperate grassland
a biome whose vegetation is dominated by grasses and features more extreme temperature differences between winter and summer and less precipitation than temperate deciduous forests. also known as steppe, prairie
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forest
any ecosystem characterized by having a high density of tress
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tropical dry forest
a biome that consists of deciduous trees and occurs at tropical and subtropical latitudes where wet and dry seasons each span about half a year. widespread in India, Africa, south america, and Northern Australia. also known as a tropical deciduous forest
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tropical rainforest
a biome that consists of year-round rain and uniformly warm temperatures. found in central america, south america, southwest Asia, west Africa, and other tropical regions
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temperate rainforest
a biome consisting of tall coniferous trees, cooler and less species full than tropical rainforests and milder and wetter than temperate deciduous forests.
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savanna
a biome characterized by grasslands interspersed with clusters of acacias and other trees. savanna is found across parts of Africa (where it was the ancestral home of our species), south america, Australia, india, and other dry tropical regions
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desert
the driest biome on earth, with annual precipitation of less than 25 cm, because deserts have relatively little vegetation to insulate them from temperature extremes, sunlight readily heats them in the daytime, but day time heat losses quality in the night, so temperatures vary widely from day to night and in different seasons
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tundra
a biome that is nearly as dry as a desert but is located at very high altitudes along the northern edges of Russia, Canada, and Scandinavia
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permafrost
in tundra, underground soil that remains more or less permanently frozen
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boreal forest
a biome of Northern coniferous forest that stretches in a broad band across much of Canada, Russia, Alaska, and Scandinavia, also known as taiga, boreal forest consists of a limited number of species of evergreen trees, such as black spruce, that dominate large regions of forest interspersed with occasional bags and lakes
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chaparral
a biome consisting mostly of densely thickened evergreen shrubs occurring in limited small patches. its "Mediterranean" climate of mild, wet winters and warm, dry summers is induced by oceanic influences. in addition to ringing the Mediterranean sea, chaparral occurs along the coast of California, Chile, and Southern Australia
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rain-shadow
a region of one side of a mountain range that experiences arid climate. this occurs because mountain moist air rising over the terrain from the opposite direction releases precipitation on the windward slope as it cools, leaving the airs humidity low, it descends over the peak and into the rain-shadow region
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watershed
the entire area of land from which water drains into a given river
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hypoxia
the condition of extremely low dissolved oxygen concentration in a body of water
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feedback loop
a circular process in which a systems output serves as input to that same system
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negative feedback loop
a feedback loop in which out put of one type acts as input that moves the system in the opposite direction. the input and output essentially neutralize each others effects, stabilizing the system
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positive feedback loop
a feedback loop in which output of one type acts as input that moves the system in the same direction. the input and output drive the system further towards on extreme or another
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emergent tree
an especially tall tree that protrudes above the canopy of tropical rain-forest
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dynamic equilibrium
the state reached when processes within a system are moving in opposing directions at equivalent rates so that their effects balance out
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homeostasis
the tendency of a system to maintain constant or stable internal conditions
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runoff
the water from precipitation that flows into streams, rivers, lakes, and ponds, and (in many cases) eventually to the ocean
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hydrosphere
all water- salt or fresh, liquid, ice, and vapor- in surface bodies, underground, and in the atmosphere
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eutrophication
the process of nutrient enrichment. increased production of organic matter, and subsequent ecosystem degradation in a water body
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airshed
the geographic area that produces air pollutants likely to end up in a waterway
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estuary
an area where a river flows into the ocean, mixing fresh and salt water
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lithosphere
the outer layer of earth, consisting of crust and uppermost mantle and located just above the asthenosphere, more generally the solid part of earth, including rocks, sediments, and sail at the surface and extending many miles underground
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primary production
the conversion of solar energy to the energy of chemical bonds in sugars during photosynthesis, performed by autotrophs
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gross primary production
the energy that results when autotrophs convert solar energy to the energy of chemical bonds in sugars during photosynthesis. autotrophs use a portion of this production to power their own metabolism, which entails oxidizing organic compounds by cellular respiration
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net primary production
the energy or biomass that remains in an ecosystem after autotrophs have metabolized enough for their own survival through cellular respiration. net primary production is the energy or biomass that is available for consumption by heterotrophs
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net primary productivity
the rate at which net primary production is produced
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secondary production
the total biomass that heterotrophs generate by consuming autotrophs
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productivity
the at which plants convert solar energy to biomass. ecosystems whose plants convert solar energy to biomass rapidly are said to have high productivity
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nutrient
an element or compound that organisms consume and require for survival
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macronutrients
elements and compounds required in relatively large amounts by organisms. examples include nitrogen, carbon, and phosphate
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micronutrients
elements and compounds required in relatively small amounts by organisms. examples include zinc, copper, and iron
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ecotone
a transitional zone where ecosystems meet
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landscape ecology
the study of how landscape structures affects the abundance, distribution, and interaction of organisms. this approach to the study of organisms and their environment. landscape studies follow broad geographical areas that include multiple ecosystems
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patch
in landscape ecology, spatial area within a landscape, depending on a researchers perspective patches may consist of habitat for a particular organism, or community, or ecosystem. an array of patches forms a mosaic
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mosaic
in landscape ecology, a spatial configuration of patches arrayed across a landscape
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nutrient cycle (biogeochemical cycle)
the comprehensive set of cycle pathways by which a given nutrient moves through the environment
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reservoir (pool)
an artificial water body behind a dam that stores water for human use
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residence time
(1) in a biogeochemical cycle, the amount of time a nutrient remains in a given pool or reservoir before moving to another. (2) in the atmosphere, the amount of time a gas molecule or pollutant stays aloft
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flux
the movement of nutrients among pools or reservoirs in a nutrient cycle
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source
in a nutrient cycle, a pool that releases more nutrients than it accepts
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sink
in a nutrient cycle, a pool that accepts more nutrients than it releases
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water cycle (hydrologic cycle)
the flow of water - in liquid, solid, or gaseous form - through our biotic and abiotic environment
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evaporation
the conversion of a substance from a liquid to a gaseous form
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transpiration
the release of water vapor by plants through their leaves
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precipitation
water that condenses out of the atmosphere and falls into earth in droplets or crystals
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ground water
water held in aquifers underground
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aquifer
an underground water reservoir
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water table
the upper limit of groundwater held in an aquifer
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carbon cycle
a major nutrient cycle consisting of the routes that carbon atoms take through the nested networks of environmental systems
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nitrogen cycle
a major nutrient cycle consisting of the routes that nitrogen atoms take through the nested networks of environmental systems
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nitrogen fixation
the process by which inert nitrogen gas combines with hydrogen to form ammonium ions (NH4+), which are chemically and biologically active and can be taken up by plants
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nitrogen-fixing bacteria
bacteria that live independently in the soil or water, or those that form mutualistic relationships with many types of plants and provide nutrients to the plants by converting gaseous nitrogen to a usable form
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nitrification
the conversion by bacteria of ammonium ions (NH4+) first into nitrite ions (NO2-) and then into nitrate ions (NO3-)
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denitrifying bacteria
bacteria that convert the nitrates in soil or water to gaseous nitrogen and release it back into the atmosphere
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Haber-Bosch process
a process to synthesize ammonia on an industrial scale. developed by german chemistFritz Haber and Carl Bosch, the process has enabled humans to double the natural rate of nitrogen fixation on earth and thereby increase agricultural productivity, but it has also dramatically altered the nitrogen cycle
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phosphorus cycle
a major nutrient cycle consisting of the routes that phosphorus atoms take through the nested networks of environmental systems
