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71 Cards in this Set
- Front
- Back
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Dead zone |
a region of water so depleted of oxygen -that marine organisms are killed or driven away |
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hypoxia |
low concentrations of dissolved oxygen in water -from fertilizer, fossil fuel emissions, runoff, sewage |
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system |
a network of relationships among parts, elements, or components -they interact with and influence one another -they exchange energy, matter, or information |
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feedback loop |
a circular process in which a system's output serves as input to that same system -negative and positive feedback loops do not mean bad and good |
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negative feedback loop |
output from a system moving in one direction acts as input -that moves the system in the other direction -input and output neutralize one another -most systems in nature |
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positive feedback loop |
instead of stabilizing a system, it drives it further toward one extreme or another -exponential growth in human populaiton, erosion, melting sea ice -rare in nature -but is common in natural systems altered by humans |
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dynamic equilibrium |
system processes move in opposing directions -balancing their effects |
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Homeostasis |
a system maintains constant (stable) internal conditions |
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Emergent properties |
system characteristics are not evident in the components alone -the whole is more than the sum of the parts |
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Eutrophication |
The process of nutrient over-enrichment leads to: -blooms of algae -increased production of organic matter -decomposition and hypoxia |
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lithosphere |
rock and sediment |
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atmosphere |
the air surrounding our planet |
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hydrosphere |
liquid, solid or vapor water |
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biosphere |
the planet's living organisms and the abiotic (nonliving) portions of the environment |
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Ecosystem |
all organisms and nonliving entities that occur and interact in a particular area at the same time |
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primary production |
conversion of solar energy to chemical energy in sugars by autotrophs |
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gross primary production (GPP) |
assimilation of energy by autotrophs |
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net primary production (NPP) |
energy remaining after respiration which is used to generate biomass -available for consumption by heterotrophs |
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secondary production |
biomass generated by heterotrophs from consuming autotrophs |
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productivity |
rate at which ecosystems generate biomass |
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high net primary productivity |
ecosystems whose plants rapidly convert solar energy to biomass |
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nutrients |
elements and compounds required for survival that are consumed by organisms |
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Macronutrients |
required in larger amounts -nitrogen, carbon, phosphorus |
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micronutrients |
nutrients needed in smaller amounts |
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ecotones |
transitional zones between two ecosystems -elements of each ecosystem mix |
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landscape ecology |
studies how landscape structure affects the abundance, distribution, and interaction of organisms -helpful for sustainable regional development |
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metapopulation |
a network of subpopulations -most members stay within patches -some individuals may move among patches or mate with those of other patches -individuals in small, isolated patches risk extinction |
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conservation biologists |
study the loss, protection, and restoration of biodiversity |
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Ecosystem services |
provided by the planet's systems -soil formation, water and air purification, pollination -breakdown of some pollutants and waste -quality of life issues (inspiration, spiritual renewal) -nutrient cycling |
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hydrologic cycle |
summarizes how liquid, gaseous and solid water flows though the environment |
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demography |
the application of population ecology to the study of change in human populations |
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The IPAT model: I=P times A times T times S |
Total impact (I) on the environment results from: -population (p)=individuals need space and resources -affluence (A)=greater per capita resource use -technology (T)=increased exploitation of resources -sensitivity (S)=how sensitive an area is to human pressure |
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biodiversity |
variety of life at all levels of organization -species diversity -genetic diversity -population and community diversity |
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ecosystem diversity |
the number and variety of ecosystems |
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extirpation |
the disappearance of a population from a given area, but not the entire species globally |
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habitat fragmentation |
gradual, piecemeals degradation of habitat |
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conservation biology |
studies the factors behind the loss, protection, and restoration of biodiversity -scientists became alarmed at the degradation of natural systems |
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conservation geneticists |
study genetic attributes of organisms to infer the status of their populations |
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minimum viable population size |
how small a population can become before it runs into problems |
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metapopulations |
a network of subpopulations -small populations are most vulnerable to extinction and need special attention |
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debt-for-nature swap |
a conservation organization pays off a portion of a developing country's international debt. in exchange, the country promises to set aside reserves to: -fund environmental education and -better manage protected areas |
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conservation concession |
conservation organizations pay nations to conserve, and not sell, resources |
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ecological restoration |
restores degraded areas to some semblance of their former condition |
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restoration ecology |
restoring damaged systems to bring back species and reestablish ecological processes |
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environmental health |
assesses environmental factors that influence human health and quality of life -including natural and human-caused factors |
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Radon |
a highly toxic radioactive gas that is colorless and undetectable |
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abestos |
a mineral that insulates, muffles sounds, and resists fire |
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toxicology |
the study of the effects of poisonous substances on humans and other organisms |
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toxicity |
the degree of harm a toxicant can inflict |
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toxicant |
any toxic substance (poison) |
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Environmental toxicology |
deals with toxic substances that come from or are discharged into the environment -studies health effects on humans, other animals, and ecosystems |
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toxins |
toxic chemicals made in tissues of living organisms |
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bioaccumulation |
toxicants build up in animal tissues |
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biomagnification |
concentrations of toxicants become magnified |
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case history approach |
studies individual patients -autopsies tell us about lethal doses -don't tell about rare, new, or low-concentration toxins -don't tell about probability and risk |
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epidemiological studies |
large-scale comparisons between exposed and unexposed groups -studies can last for years -yield accurate predictions about risk -measure an association between a health hazard and an effect-but not necessarily the cause of the effect |
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dose-response analysis |
measures the effect a toxicant produces or the number of animals affected -at different doses |
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dose |
amount of substance the test animal receives |
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response |
the type or magnitude of negative effects |
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dose-response curve |
the dose plotted against the response |
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acute exposure |
high exposure to a hazard for short periods of time -easy to recognize -stem from discrete events: ingestion, oil spills, nuclear accident, etc. |
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chronic exposure |
low exposure for long periods of time -more common but harder to detect and diagnose -affects organs gradually: lung cancer, liver damage -cause and effect may not be easily apparent |
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synergistic effects |
interactive impacts that are greater than the sum of their constituent effects |
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risk |
the probability that some harmful outcome will result from a given action, event, or substance |
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fossil fuels |
highly combustible substances from the remains of organisms from past geologic ages -oil, coal, and natural gas have replaced biomass as our dominant sources of energy |
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electricity |
a secondary form of energy that is easy to transfer and apply to a variety of uses |
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renewable energy |
supplies that will not be depleted by our use -sunlight, geothermal energy, and tidal energy |
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nonrenewable energy |
we will use up Earth's accessible store in decades to centuries -oil, coal, natural gas, nuclear energy -to replenish the fossil fuels we have depleted so far would take millions of years |
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aerobic decomposition |
organic material is broken down and recycled in the presence of air |
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anaerobic decomposition |
occurs with little or no air -deep lakes, swamps -produces fossil fuels |
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net energy |
the difference between energy returned and energy invested |
