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45 Cards in this Set
- Front
- Back
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Characteristics of Populations
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*geographic distribution
*density *groth rate |
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Population density
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the number of individuals per unit area.
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Three factors that can affect populations size
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*births
*death *individuals enter or leave a population |
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Immigration
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the movement of individuals into an area
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Emigration
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the movement of of individuals out
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Exponential growth
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occurs when the individuals in a population reproduce at a constant rate.
***"J curve" |
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Logistic growth
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occurs when a population growth slows or stops folling a period of exponential growth
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carrying capacity
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the number an environment can support
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Limiting factor
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*predation causes another population to decrease.
*causes a decrease in population |
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density-dependent limiting factor
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*limiting only when the population density reaches a certain level
*competition, predation, parasitism, disease |
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Predator-prey relationship
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one of the best-known mechanisms of population control
*the regulation of a population by predation. |
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Density-independent limiting factors
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*affects all population in similar ways
*weather, natural disasters, seasonal cycles, human activity. |
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demography
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*the study of the human population.
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demographic transition
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*dramatic change in birth and death rates.
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age-structure diagrams
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*population profiles
*demographers can predict the future growth using models |
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Biosphere
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*hunting/gathering
*agriculture *industry *urban development |
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hunting and gathering
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*human ancestors obtained food by hunting and gathering.
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Agriculture
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the science and art of farming which includes cultivation of field soils, production of crops, raising of livestock.
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monoculture
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large planted fields are planted with a single variety year after year
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Green revolution
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*increase in food production
*modern agriculture techniques |
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Industrial Growth and Urban Development
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*human society and its impact on the biosphere
**ecologists are concerned about the efects of human activity on both local and global environments. *Pollution in the air, water and soil |
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Renewable resources
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*CAN regenerate by natural processes
*example: tree, grass, water |
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Non-renewable resources
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CANNOT by replenished by natural proccesses.
*example: fossil fuesl, coal, oil |
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Sustainable developments
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*a way of using natural resources without depleting them and of providing for human needs without causing long term environmental harm.
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soil erosion
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wearing away of surface soil
causes of erosion: roots, plowing, water and wind |
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desertification
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*dry climates with a combination of farming, overgrazing and drought causes desertification
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deforestation
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loss of forests
*can lead to soil erosion |
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Aquaculture
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raising of aquatic animals for human consumption
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Fishery resources
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*valuable food source for human consumption
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Smog
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*mixture of chemicals that occurs as a gray-brown haze in the atmosphere
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Pollutant
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Harmful material that can enter the biosphere
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Acid rain
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*combustion processes like burning fossil fuels realease nitrogen and sulfur compounds into the atmosphere.
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biodiversity
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the sum total of the genetically based vareity of all organisms in the biosphere.
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Ecosystem diversity
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includes the variety of habitats, communities, and exological processes in the living world.
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species diversity
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refers to the number of different species in the biosphere.
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Genetic diversity
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*refers to the sum total of all the different forms of genetic information carried by all organisms living on earth today.
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What threatens biodiversity
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*human activity can reduce biodiversity by altering habitats, hunting species to extinction.
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Extinction
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*occures when a species disappears from all or part of its range.
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endangered species
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* a species whose population size is declining in a way that places it in danger of extinction.
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habitat fragmentation
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development often splits ecosystems into pieces.
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biological magnification
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concentrations of harmful substance increase in organisms at higher trophic levels in a food chain or food web.
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invasive species
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reproduce rapidly and increase their populations because their new habitat lacks the parasites and predators that control their population.
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Conservation
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used to describe the wise management of natural resources, including the preservation of habitats and wildlife.
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ozone layer
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the atmosphere contains a relatively high concentration of ozone gas.
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global warming
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term used to describe the increase in the average temperature of the biosphere.
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