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BIOL 1060: EXAM 2
7 billion |
Human population growth:
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technology, medical care, sanitation, and food. |
What does population growth result from?
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IPAT model |
Our total impact (I) on the environment results from the interaction of population (P), affluence (A), and technology (T).
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Demography |
the application of population ecology to the study of human populations
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Extreme climate biomes (desert, deep rainforest, and tundra) |
Where is population density the lowest?
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temperate, subtropical, and tropical climates (China, Europe, Mexico, South Africa, and India) |
Where is population density the highest?
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total fertility rate (TFR) |
the average number of children born per female
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replacement fertility |
TFR that keeps the size of a population stable
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2.1 |
For humans, replacement fertility =
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Urbanization |
What decreases TFR?
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Natural rate of population change |
population change due to birth and death rates alone
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Life Expectancy |
the average number of years that an individual in a particular age group is likely to continue to live.
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demographic transition |
a model of economic and cultural change that explains the trend of declining death rates and birth rates that occurs when nations become industrialized.
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pre-industrial stage |
characterized by conditions in which both death rates and birth rates are high.
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transitional stage |
death rates decline and birth rates remain high.
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industrial stage |
creates employment opportunities, particularly for women, causing the birth rate to fall.
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post-industrial stage |
both birth rates and death rates remain low and populations stabilize or decline slightly
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population growth |
What is population strongly correlated with?
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environmental impact |
Consumption from affluence creates ...?
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agriculture
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the practice of cultivating soil, producing crops, and raising livestock for human use and consumption
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rangeland |
pasture, the land used for livestock.
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large-scale fossil-fuel combustion&mechanization |
What did the industrial revolution introduce?
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mix of rock, organic matter, water, gases, nutrients, and microorganisms |
What is healthy soil?
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50% mineral matter,up to 5% organic matter, &the rest is pore space filled with air or water |
What does soil consist of?
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parent material |
base geological material in a location. It may be composed of volcanic deposits, glacier deposits, sediments from wind or water, or bedrock.
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weathering |
the physical, chemical, and biological processes that break down rocks and minerals.
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deposition, decomposition, and accumulation of organic matter |
Biological activity helps soil formation through
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erosion |
the process of moving soil from one area to another, may contribute to the formation of soil in one locality even as it depletes topsoil from another.
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horizon |
Soils can be divided into recognizable layers, or a __________
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soil profile |
The cross-section of soil from bedrock to surface
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leaching |
picks up minerals and particles in the soil and transports them to another location, generally downward.
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A horizon (topsoil) |
The crucial horizon for agriculture and ecosystems
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topsoil |
consists of mostly inorganic mineral components with some organic matter and humus.
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forest removal, cropland agriculture, and overgrazing by livestock. |
What is soil degradation caused by?
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Common problems affecting soil productivity include: |
erosion, desertification, salinization, waterlogging, nutrient depletion, structural breakdown, and pollution.
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erosion |
the removal of material from one place and its transport to another by the action of wind or water.
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deposition |
the arrival of eroded material at its new location.
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splash, sheet, rill, and gully. |
4 types of water erosion:
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desertification |
loss of more than 10% productivity due to soil erosion, soil compaction, forest removal, overgrazing, drought, salinization, climate change, depletion of water sources, or an array of other factors.
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crop rotation |
the practice of alternating the kind of crop grown in a particular field from one season or year to the next.
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contour farming |
consists of plowing furrows along the natural contours of the land.
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terracing |
cutting level platforms into hillsides, is used on extremely steep terrain.
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intercropping |
The planting of alternating bands of different crops across a slope is called
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shelterbelts |
rows of trees that are planted along the edges of fields to break the wind.
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irrigation |
Crops that require a great deal of water can be grown with ______, artificial provision of water.
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waterlogging |
happens when soils become too saturated with water, damaging soil and suffocating plant roots.
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salinization |
the buildup of salts in surface soil layers.
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inorganic fertilizers |
mined or synthetically manufactured mineral supplements.
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overgrazing |
when too many animals eat too much plant cover, impeding plant growth and replacement of biomass.
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increased erosion, invasion of non-native plants, and compacted soil |
What can overgrazing result in?
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malnutrition |
Those who receive too few nutrients suffer from
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overnourished
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Those who receive too many calories each day are
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food security |
the guarantee of an adequate, reliable, and available food supply to all people at all times.
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monoculture |
Industrialized agriculture plants huge fields of a single type of crop,
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green revolution |
Farmers in the United States had been dramatically increasing their yields using new methods and technology.
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pest |
any organism that damages crops that are valuable to us
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weed |
any plant that competes with our crops.
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pesticides |
Poisons that target pest organisms are termed
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biocontrol |
operates on the principle that “the enemy of one’s enemy is one’s friend.” We find natural enemies, or predators, of a species we consider a pest, and introduce them to an area where the pests are a problem.
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integrated pest management |
uses numerous techniques, including biocontrol, chemicals, population monitoring, habitat alteration, crop rotation, transgenic crops, alternative tillage methods, and mechanical pest removal.
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pollination |
the process by which male sex cells of a plant (pollen) fertilize female sex cells of the same species of plant; it is the botanical version of sexual intercourse.
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genetic engineering |
any process whereby scientists directly manipulate an organism’s genetic material in the lab by adding, deleting, or changing segments of DNA.
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genetically modified organisms |
organisms that have been genetically engineered using recombinant DNA technology, developed in the 1970s by scientists studying the Escherichia coli bacterium.
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biotechnology |
the material application of biological science to create products derived from organisms.
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seed banks |
institutions store seeds from crop varieties, keeping them in cold, dry conditions to encourage long-term viability.
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feedlots or factory farms |
concentrated animal feeding operations in which animals are housed in huge warehouses or pens where energy-rich food is provided to animals living at extremely high densities.
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greater the proportion of the sun’s energy we put to use as food, and the more people Earth can support |
The lower in the food chain our food sources are
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aquaculture |
Raising fish and shellfish on “fish farms” in controlled environments is
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sustainable agriculture |
farming that does not deplete soils faster than they form and does not reduce the amount of healthy soil, clean water, and genetic diversity essential to long-term crop and livestock production.
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low-input agriculture |
farming that uses smaller amounts of pesticides, fertilizers, growth hormones, water, and fossil fuel energy than is used in industrial agriculture
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organic agriculture |
Food growth practices that use no synthetic fertilizers or pesticides are
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biological diversity |
the sum total of all organisms in an area, taking into account the diversity of species, their genes, their populations, and their communities.
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species diversity |
expressed in terms of the number or variety of species in the world or in a particular region.
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taxonomists |
the scientists who classify species
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speciation |
the generation of new species, adds to species diversity, while extinction decreases species diversity.
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subspecies |
Biodiversity exists below the species level in the form of
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genetic diversity |
encompasses the differences in DNA composition among individuals within species and populations.
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ecosystem diversity |
Biodiversity exists above the species level in the form of
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extirpation |
the extinction of a certain population from a given area, but not the entire species globally, is called
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background rate of extinction
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Most extinctions preceding the appearance of humans have occurred one by one, at a rate that paleontologists refer to as the
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Major causes of biodiversity loss |
Habitat alteration
Invasive species Pollution Overharvesting Climate change All five of the primary causes for population declines are exacerbated by human population growth and rising per capita consumption.
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conservation biology |
a scientific discipline devoted to understanding the factors, forces, and processes that influence the loss, protection, and restoration of biological diversity.
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biodiversity hotspots |
areas that support an especially great diversity of species, particularly species that are endemic to the area, that is, found nowhere else in the world.
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urbanization |
The shift from rural to urban living, may be the single greatest change our society has undergone since we changed from a nomadic hunter-gatherer lifestyle to a sedentary agricultural one
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sprawl |
term that has become laden with meanings, but simply, it is the spread of low-density urban or suburban development outward from an urban center.
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city planning |
the professional pursuit that attempts to design cities so as to maximize their efficiency, functionality, and beauty.
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zoning |
the practice of classifying areas for different types of development and land use.
involves government regulation on private land use and is often viewed as a constraint on personal property rights
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resource consumption |
cities and towns must import from widespread regions nearly everything they need to feed, clothe, and house their inhabitants.
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resource management |
the practice of harvesting potentially renewable resources in ways that do not deplete them
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forestry |
the profession of managing forests, balancing the central importance of forests as ecosystems with the demand for wood products.
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maximum sustainable yield |
the maximum amount of resource extraction possible while not depleting the resource from one harvest to the next.
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ecosystem-based management |
attempts to manage the harvesting of resources in ways that minimize impacts on the ecosystems and ecological processes that provide the resource.
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adaptive management |
involves systematically testing different management approaches with the aim of improving methods as time goes on, including changing practices in midstream if necessary
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deforestation |
has altered ecosystems and caused soil degradation, population declines, and species extinctions.
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clear-cutting |
the easiest and most cost-efficient method in the short term, but it has the greatest impacts on forest ecosystems
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salvage logging |
In the wake of the 2003 California fires, the U.S. Congress passed the Healthy Forests Restoration Act, which encourages prescribed burns and physical removal of small trees, underbrush, and dead trees by timber companies, called
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national parks |
publicly held lands protected from extraction and development but open to the public for nature appreciation and recreation.
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national wildlife refuge |
another type of protected area and is managed by the U.S. Fish and Wildlife Service.
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land trusts |
local and regional organizations that preserve lands in their natural condition.
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biosphere reserves |
tracts of land with exceptional biodiversity that couple preservation with sustainable development to benefit the local people.
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