environmental mid-term notes
TRANSCRIPT
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Environmental Mid-Term Notes
Chapter 1
Environmental science is the study of: 1. How the natural world works 2. How theenvironment affects humans and vice versa.
All the things around us with which we interact:
Living things
Animals, plants, forests, fungi, etc.
Nonliving things
Continents, oceans, clouds, soil, rocks
Our built environment
Buildings, human-created living centers
Natural resources = substances and energy sources needed for survival
Renewable resources: Perpetually available: sunlight, wind, wave energy Renew themselves
over short periods: timber, water, soil These can be destroyed
Nonrenewable resources: can be depleted Oil, coal, minerals
Overshoot: humans have surpassed the Earth’s capacity
Environment impacts Humans
•Environmental science
• The pursuit of knowledge about the natural world
• Scientists try to remain objective
•Environmentalism
• A social movement dedicated to protecting the natural world
• Science:
- A systematic process for learning about the world and testing our understanding of
it
- A dynamic process of observation, testing, and discovery
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- The accumulated body of knowledge that results from this process
A scientist makes an observation and asks questions of some phenomenon
• The scientist formulates a hypothesis, a statement that attempts to explain the scientific
question.
• The hypothesis is used to generate predictions, which are specific statements that can be
directly and unequivocally tested.
• The test results either support or reject the hypothesisManipulative experiments yield the strongest evidence
• But, lots of things can’t be manipulated
Natural or correlational tests show real-world complexity
• Results are not so neat and clean, so answers aren’t simply black and white
• Many people think environmental conditions are better
• Cornucopians: Human ingenuity will solve any problem
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• Some think things are much worse in the world
• Cassandras: predict doom and disaster
Chapter 2
Culture = knowledge, beliefs, values, and learned ways of life shared by a group of people
Worldview = a person’s or group’s beliefs about the meaning, purpose, operation, and essence
of the world
• Ethics = the study of good and bad, right and wrong
-
Relativists = ethics varies with social context
- Universalists = right and wrong remains the same across cultures and situations
• Ethical standards = criteria that help differentiate right from wrong
- Classical standard = virtue
- The golden rule
-Utility = something right produces the most benefits for the most people
• Environmental ethics = application of ethical standards to relationships between humanand non-human entities
- Anthropocentrism = only humans have rights
- Biocentrism = certain living things also have value
-
Ecocentrism = whole ecological systems have value
- Holistic perspective, stresses preserving connections
Transcendentalism = nature is a manifestation of the divine Ralph Waldo Emerson, Henry
David Thoreau
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• Deep ecology = humans are inseparable from nature
• Since all living things have equal value, they should be protected
• Ecofeminism = male-dominated societies have degraded women and the environment
through fear and hate
• Female worldview = cooperation
• Environmental justice = the fair and equitable treatment of all people regarding
environmental issues
• Wealthy nations dump hazardous waste in poorer nations with uninformed residents
Economy = a social system that converts resources into
• Goods: manufactured materials that are bought, and
• Services: work done for others as a form of business
• Subsistence economy = people get their daily needs directly from nature; they do not
purchase or trade
• Capitalist market economy = buyers and sellers interact to determine prices and
production of goods and services
• Centrally planned economy = the government determines how to allocate resources
• Mixed economy = governments intervene to some extent
• Ecosystem services = essential services support the life that makes economic activities
possible
*Soil formation *Pollination
*Water purification *Nutrient cycling
*Climate regulation *Waste treatment
Discounting = short-term costs and benefits are more important than long-term costs and
benefits
Ecological economists = civilizations cannot overcome environmental limitations
• Steady state economies should mirror natural ecological systems
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• Calls for revolution
• Environmental economists = unsustainable economies have high population growth andinefficient resource use
- Modify neoclassical economics to increase efficiency
- Calls for reform
Gross Domestic Product (GDP) = total monetary value of final goods and services produced
• Does not account for nonmarket values
• Pollution increases GDP
Genuine Progress Indicator (GPI) = differentiates between desirable and undesirable
economic activity
Chapter 3
Policy = a formal set of general plans and principles to address problems and guide decisions
Public Policy = policy made by governments that consists of laws, regulations, orders,incentives, and practices
Environmental Policy = pertains to human interactions with the environment
Regulates resource use or reduce pollution
Policy = a formal set of general plans and principles to address problems and guide decisions
Public Policy = policy made by governments that consists of laws, regulations, orders,incentives, and practices
Environmental Policy = pertains to human interactions with the environment
Regulates resource use or reduce pollution
Free Riders = reducing pollution tempts any one person to cheat
Private voluntary efforts are less effective than mandated efforts
External Cost = harmful impacts result from market transaction but are borne by people not
involved in the transaction
Legislative branch = creates statutory law
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Executive branch = enacts or vetoes legislation
Issues executive orders
Judicial branch = interprets laws
Administrative agencies = the “fourth branch”
Customary law = practices or customs held by most cultures
Conventional law = from conventions or treaties
United Nations Environment Programme (UNEP) = helps nations understand and solve
environmental problems
The European Union seeks to promote Europe’s unity and economic and social progress
Nongovernmental Organizations (NGOs) = entities that influence international policy
The World Bank = one of the world’s largest funding sources for development
Risk assessment = judging risks a problem poses to health or the environment
Risk management = developing strategies to minimize risk
Lobbying = spending time and money to influence a politician
Environmental advocates are not the most influential lobbyists
Political Action Committees (PACs) = raise money for political campaigns
The revolving door = the movement of people between the private sector and government
Intimate knowledge of an issue or conflict of interest?
Command-and-control approach: environmental policy sets rules or limits and threatens
punishment for violators
Tax breaks = encourage desirable industries or activities
Subsidy = a government giveaway of cash or resources to encourage a particular activity
Green taxes = taxes on environmentally harmful activities
Permit trading = government-created market in permits
Businesses buy, sell, trade these permits
Emissions trading system = government-issued permits for an acceptable amount of pollution
and companies buy, sell, or trade these permits with other polluters
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Cap-and-trade system = a party that reduces its pollution levels can sell this credit to other
parties
Chapter 4
Bioremediation= pollution cleanup through enhanced natural biodegradation
Matter = all material in the universe that has mass and occupies space
Element = a fundamental type of matter, with a given set of properties
Atoms = the smallest components that maintain an element’s chemical properties
The atom’s nucleus has protons (positively charged particles) and neutrons (particles lacking
electric charge)
Atomic number = the defined number of protons
Electrons = negatively charged particles surrounding the nucleus
Balances the positively charged protons
Isotopes = atoms with differing numbers of neutrons
Mass number = the combined number of protons and neutrons
Isotopes of an element behave differently
Chapter 5
Biological evolution = genetic change in populations of organisms across generations
May be random or directed by natural selection
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Natural Selection = the process by which traits that enhance survival and reproduction are
passed on more frequently to future generations than those that do not
Adaptive Trait (Adaptation) = a trait that promotes reproductive success
Mutations = accidental changes in DNA that may be passed on to the next generation
Directional selection = drives a feature in one direction
Stabilizing selection = produces intermediate traits, preserving the status quo
Disruptive selection = traits diverge in two or more directions
Artificial Selection = the process of selection conducted under human direction
Biological Diversity = An area’s sum total of all organisms
The diversity of species
Their genes
Their populations
Their communities
Species = a population or group of populations whose members share characteristics and canfreely breed with one another and produce fertile offspring
Population = a group of individuals of a species that live in the same area
Allopatric speciation = species formation due to physical separation of populations
Sympatric speciation = species form from populations that become reproductively isolatedwithin the same area
Phylogenetic trees (Cladograms) = Represents the history of species divergence
Extinction = the disappearance of a species from Earth
Occurs when a species cannot adapt quickly enough to a changing environment
Speciation and extinction affect species numbers
Endemic species = a species only exists in a certain, specialized area
Very susceptible to extinction
These species usually have small populations
Many other factors also cause extinction
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Severe weather
New species
Specialized species
Endemic species = a species only exists in a certain, specialized area
Very susceptible to extinction
These species usually have small populations
Many other factors also cause extinction
Severe weather
New species
Specialized species
Biosphere = the total living things on Earth and the areas they inhabit
Ecosystem = communities and the nonliving material and forces they interact with
Community = interacting species that live in the same area
Population ecology = investigates the quantitative dynamics of how individuals within aspecies interact
Community ecology = focuses on interactions among species
Ecosystem ecology = studies living and nonliving components of systems to reveal patterns
Nutrient and energy flows
Habitat = the environment in which an organism lives
Includes living and nonliving elements
Scale-dependent: from square meters to miles
Habitat use = each organism thrives in certain habitats, but not in others
Habitat selection = the process by which organisms actively select habitats in which to live
Availability and quality of habitat are crucial to an organism’s well-being
Human developments conflict with this process
Niche = an organism’s use of resources and its functional role in a community
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Habitat use, food selection, role in energy and nutrient flow
Interactions with other individuals
Specialists = species with narrow niches and very specific requirements
Extremely good at what they do, but vulnerable to change
Generalists = species with broad niches that can use a wide array of habitats and resources
Able to live in many different places
Population size = the number of individual organisms present at a given time
Population distribution (dispersion) = spatial arrangement of organisms within an area
Natality = births within the population
Mortality = deaths within the population
Immigration = arrival of individuals from outside the population
Emigration = departure of individuals from the population
Growth rate formula =
(Crude birth rate + immigration rate) - (Crude death rate + emigration rate) = Growth rate
exponential population growth
Something increases by a fixed percent
Graphed as a J-shaped curve
Limiting factors = physical, chemical and biological characteristics that restrain
population growth
Water, space, food, predators, and disease
Environmental resistance = All limiting factors taken together
Carrying capacity = the maximum population size of a species that its environment can sustain
An S-shaped logistic growth curve
Limiting factors slow and stop exponential growth
Carrying capacity changes
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Density-dependent factors = limiting factors whose influence is affected by population density
Increased risk of predation and competition for mates occurs with increased density
Density-independent factors = limiting factors whose influence is not affected by population
density
Events such as floods, fires, and landslides
Chapter 6
Species interactions are the backbone of communities
Most important categories
Competition = both species are harmed
Predation, parasitism, and herbivory = one species benefits and the other is harmed
Mutualism = both species benefit
Competition = relationship where multiple organisms seek the same limited resources they
need to survive:
Food - Water
Space - Shelter
Mates - Sunlight
Intraspecific competition = between members of the same species
High population density = increased competition
Interspecific competition = between members of 2 or more species
Leads to competitive exclusion or species coexistence
Competitive exclusion = one species completely excludes another species from using theresource
Species coexistence = neither species fully excludes the other from resources, so both live side by side
Fundamental niche = when an individual fulfills its entire role by using all the availableresources
Realized niche = the portion of the fundamental niche that is actually filled
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Resource partitioning = when species divide shared resources by specializing in different ways
Character displacement = competing species evolve physical characteristics that reflect their reliance on the portion of the resource they use
Exploitation = one member exploits another for its own gain
Predation, parasitism, herbivory
Predation = process by which individuals of one species (predators) capture, kill, and consumeindividuals of another species (prey)
Parasitism = a relationship in which one organism (parasite) depends on another (host) for nourishment or other benefit
Coevolution = hosts and parasites become locked in a duel of escalating adaptations
Symbiosis = mutualism in which the organisms live in close physical contact
Microbes within digestive tracts
Plants and fungi
Pollination = bees, bats, birds and others transfer pollen from one flower to another, fertilizing
its eggs
Amensalism = a relationship in which one organism is harmed while the other is unaffected
Difficult to confirm, because usually one organism benefits from harming another
Allelopathy = certain plants release harmful chemicals
Or, is this competition?
Commensalism = a relationship in which one organism benefits, while the other remainsunaffected
Facilitation = plants that create shade and leaf litter allow seedlings to grow
Community = an assemblage of species living in the same place at the same time
Members interact with each other
Interactions determine the structure, function, and species composition of the community
Community ecologists = people interested in how:
Species coexist and relate to one another
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Communities change, and why patterns exist
Trophic levels = rank in the feeding hierarchy
Producers
Consumers
Detritivores and Decomposers
Autotrophs (“self-feeders”) = organisms that capture solar energy for photosynthesis to produce
sugars
Green Plants
Cyanobacteria
Algae
Chemosynthetic bacteria use the geothermal energy in hot springs or deep-sea vents to produce their food
Primary consumers = second trophic level
Organisms that consume producers
Herbivores consume plants
Deer, grasshoppers
Secondary consumers = third trophic level
Organisms that prey on primary consumers
Carnivores consume meat
Wolves, rodents
Tertiary Consumers = fourth trophic level
Predators at the highest trophic level
Consume secondary consumers
Are also carnivores
Hawks, owls
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Omnivores = consumers that eat both plants and animals
Detritivores = scavenge waste products or dead bodies
Millipedes
Decomposers = break down leaf litter and other non-living material
Fungi, bacteria
Enhance topsoil and recycle nutrients
Food chain = the relationship of how energy is transferred up the trophic levels
Food web = a visual map of feeding relationships and energy flow
Includes many different organisms at all the various levels
Greatly simplified; leaves out the majority of species
Keystone Species = has a strong or wide-reaching impact far out of proportion to its abundance
Trophic Cascade = predators at high trophic levels can indirectly affect populations of organisms at low trophic levels by keeping species at intermediate trophic levels in check
Resistance = community of organisms resists change and remains stable despite the disturbance
Resilience = a community changes in response to a disturbance, but later returns to its original
state
Succession = the predictable series of changes in a community following a disturbance
Primary succession = disturbance eliminates all vegetation and/or soil life
• Glaciers, drying lakes, volcanic lava
Pioneer species = the first species to arrive in a primary succession area (ex, lichens)
Secondary succession = a disturbance dramatically alters, but does not destroy, all localorganisms
The remaining organisms form “building blocks” for the next population species
Fires, hurricanes, farming, logging
Climax community = the community resulting from successful succession
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Remains stable
until another
disturbance restartssuccession
Invasive species = non-native (exotic) organisms that spread widely and become dominant in acommunity
Ecological restoration = returning an area to unchanged conditions
Deciduous trees lose their leaves each fall and remain dormant during winter
Chapter 7
Hypoxia = low concentrations of dissolved oxygen water
System = a network of relationships among parts elements or components that interact with and
influence one another
Feedback loop = a system’s output serves as input to that same system
Negative feedback loop = output that results from a system moving in one direction acts asinput that moves the system in the other direction.
Positive feedback loop = instead of stabilizing a system, it drives it further toward one extremeor another
Dynamic equilibrium = system processes move in opposing directions at equivalent rates,
balancing their effects
Homeostasis = a system maintains constant or stable internal conditions
Emergent properties = system characteristics not evident in the components alone
Lithosphere = rock and sediment
Atmosphere = the air
Hydrosphere = liquid, solid or vapor water
Biosphere = all the planet’s living organisms and the abiotic portions of the environment
Ecosystem = all organisms and nonliving entities that occur and interact in a particular area at
the same time
Primary production = conversion of solar energy to chemical energy by autotrophs
Gross primary production (GPP) = assimilation of energy by autotrophs
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Net primary production (NPP) = energy remaining after respiration, and is used to generate
biomass
Available for heterotrophs
Secondary production = biomass generated by heterotrophs
High net primary productivity = ecosystems whose plants rapidly convert solar energy to
biomass
Nutrients = elements and compounds required for survival that are consume by organisms
Macronutrients = nutrients required in relative large amounts
Nitrogen, carbon, phosphorus
Micronutrients = nutrients needed in smaller amounts
Stimulate plant production
Nitrogen and phosphorus
are important for plant and
algal growth
Ecotones = transitional zones between two ecosystems in which elements of different
ecosystems mix
Landscape ecology = the study of landscape structure and how it affects the abundance,
distribution, and interaction of organisms
Helpful for sustainable regional development
Patches = form the landscape, and are distributed spatially in complex patterns (a mosaic)
Landscape = larger than an ecosystem and smaller than a biome
Metapopulation = a network of subpopulations
Most members stay within patches but may move among patches or mate with those of other
patchesIndividuals in small patches risk extinction
Conservation biologists = study the loss, protection, and restoration of biodiversity
Habitat fragmentation = breaking habitat into small, isolated patches due to human impact
Geographic information system (GIS) = computer software used in landscape ecology
research
Nutrient (biogeochemical) cycle = the movement of nutrients through ecosystems
Atmosphere, hydrosphere, lithosphere, and biosphere
Pools (reservoirs) = where nutrients reside for varying amounts of time
Flux = movement of nutrients among pools, which change over time and are influenced by
human activitiesSources = pools that release more nutrients than they accept
Sinks = accept more nutrients than they release
Carbon cycle = describes the routes that carbon atoms take through the environment
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The carbon cycle
Humans affect the carbon cycle
• Burning fossil fuels moves carbon from the ground to the air
• Cutting forests and burning fields moves carbon from organisms to the air
• Today’s atmospheric carbon dioxide reservoir is the largest in the past 650,000 years
-
The driving force behind climate change
• The missing carbon sink: 1-2 billion metric tons of carbon are unaccounted for
- It may be the plants or soils of northern temperate and boreal forests
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Phosphorus cycle = describes the routes that phosphorus atoms take through the environment
No significant atmospheric component
Most phosphorus is within rocks and is released by weathering
With naturally low environmental concentrations, phosphorus is a limiting factor for plantgrowth
Humans affect the phosphorus cycle
• Mining rocks for fertilizer moves phosphorus from the soil to water systems
- Wastewater discharge also releases phosphorus
• Runoff containing phosphorus causes eutrophication of aquatic system
The nitrogen cycle
• Nitrogen comprises 78% of our atmosphere, and is contained in proteins, DNA and RNA
• Nitrogen cycle = describes the routes that nitrogen atoms take through the environment
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- Nitrogen gas is inert and cannot be used by organisms
• Nitrogen fixation = Nitrogen gas is combined (fixed) with hydrogen by nitrogen-fixing bacteria to become ammonium
- Which can be usedby plants
Nitrification = bacteria that convert ammonium ions first into nitrite ions then into nitrate ions
Plants can take up these ions
Animals obtain nitrogen by eating plants or other animals
Denitrifying bacteria = convert nitrates in soil or water to gaseous nitrogen, releasing it
back into the atmosphere
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Humans affect the nitrogen cycle
Haber-Bosch process = synthetic production of fertilizers by combining nitrogen and hydrogento synthesize ammonia
Dramatically changed the nitrogen cycle
Humans are fixing as much nitrogen as nature does
Increased emissions of nitrogen-containing greenhouse gases
Calcium and potassium in soil washed out by fertilizers
Acidified water and soils
Moved more nitrogen into plants and terrestrial systems
Reduced biodiversity of plants adapted to low-nitrogen soils
Changed estuaries and coastal ecosystems and fisheries
The hydrologic cycle
Water is essential for biochemical reactions and is involved in nearly every environmental
system
Hydrologic cycle = summarizes how liquid, gaseous and solid water flows through the
environment
Oceans are the main reservoir
Evaporation = water moves from aquatic and land systems to air
Transpiration = release of water vapor by plants
Precipitation = condensation of water vapor as rain or snow
Aquifers = underground reservoirs of sponge-like regions of rock and soil that hold …
Groundwater = water found underground beneath layers of soil
Water table = the upper limit of groundwater held in an aquifer
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Human impacts on hydrologic cycle
Damming rivers increases evaporation and infiltration
Altering the surface and vegetation increases runoff and erosion
Spreading water on agricultural fields depletes rivers, lakes and streams
Removing forests and vegetation reduces transpiration and lowers water tables
Emitting pollutants changes the nature of precipitation
The most threatening impact is overdrawing groundwater for drinking, irrigation, and industrialuse
The rock cycle
Rock cycle = The heating, melting, cooling, breaking and reassembling of rocks and minerals
Rocks help determine soil chemistry, which influences ecosystems
Helps us appreciate the formation and conservation of soils, mineral resources, fossil fuels, andother natural resources
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Igneous rock
Magma = the molten, liquid state of rock
Lava = magma released from the lithosphere
Igneous rock = forms when magma cools
Intrusive rock = magma that cools slowly well below Earth’s surface (i.e., granite)
Extrusive rock = magma ejected from a volcano (i.e., basalt)
Sedimentary rock
Sediments = particles of rock are blown by wind or washed away by water
Sedimentary rock = dissolved minerals seep through sediment layers and crystallize and bind
sediment particles together
Lithification = formation of rock through the processes of compaction, binding, andcrystallization
Formation of sedimentary rock
• Some rock is formed by chemical means when rocks dissolve and their components
crystallize to form new rock
- Limestone and rock salt
• Other rocks are formed when layers of sediment compress and physically bond to one
another
- Conglomerate, sandstone, shale
Metamorphic rock
Metamorphic rock = great heat or pressure on a rock changes its form
Temperatures is high enough to reshape crystals and change its appearance and physical properties
Marble = heated and pressurized limestone
Slate = heated and metamorphosed shale
Plate tectonics = process that underlies earthquakes and volcanoes and that determines the
geography of the Earth’s surface
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Crust = lightweight thin component of Earth’s surface
Mantle = malleable layer on which the crust floats
Core = molten heavy center of Earth made mostly of iron
Pangaea = at least twice in Earth’s history, all landmasses were joined in one supercontinent
Divergent plate boundaries = magma surging upward to the surface divides plates and pushesthem apart, creating new crust as it cools and spreads
Transform plate boundary = two plates meet, slipping and grinding alongside one another
Convergent plate boundaries = where plates collide
Subduction = one plate of crust may slide beneath another
Chapter 8
Demography = the application of population ecology to the study of humans
Total fertility rate (TFR) = the average number of children born per female
Replacement fertility = TFR that keeps the size of a population stable
Natural rate of population change = due to birth and death rates alone
In countries with good sanitation, health care, and food, people live longer
Life expectancy = average number of years that an individual is likely to continue to live
Demographic transition = a model of economic and cultural change to explain the decliningdeath and birth rates in industrializing nations
Demographic fatigue = governments face overwhelming challenges related to populationgrowth.
Chapter 9
Agriculture = practice of raising crops and livestock for human use and consumption
Cropland = land used to raise plants for human use
Rangeland or pasture = land used for grazing livestock
Soil = a complex plant-supporting system consisting of disintegrated rock, organic matter, water,gases, nutrients, and microorganism
Traditional agriculture = biologically powered agriculture, using human and animal muscle power
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Subsistence agriculture = families produce only enough food for themselves
Intensive agriculture = produces excess food to sell
Uses animals, irrigation and fertilizer, but not fossil fuels
Industrialized agriculture = using large-scale mechanization and fossil fuels to boost yields
Also uses pesticides, irrigation and fertilizers
Monocultures = uniform planting of a single crop
Green revolution = the use of new technology, crop varieties and farming practices introducedto developing countries
soil formation is slow and complex
Parent material = the base geologic material of soil
Lava, volcanic ash, rock, dunes
Bedrock = the continuous mass of solid rock comprising the Earth’s crust
Weathering = the physical, chemical, or biological processes that break down rocks to form soil
Physical (mechanical) = wind and rain, no chemical changes in the parent material
Chemical = substances chemically interact with parent material
Biological = organisms break down parent material
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• Erosion = the dislodging and movement of soil by wind or water
- Occurs when vegetation is absent
• Biological activity includes deposition, decomposition, and accumulation of organic
matter
- Humus = a dark, spongy, crumbly mass of material formed by partial
decomposition
Horizon = each layer of soil
Soil profile = the cross-section of soil as a whole
Up to six major horizons may occur in a soil profile
Topsoil = inorganic and organic material most nutritive for plants
Leaching = dissolved particles move down through horizons
Soil color = indicates its composition and fertility
Black or dark brown = rich in organic matter
Pale gray or white = indicates leaching
Soil texture = determined by the size of particles
From smallest to largest = clay, silt, sand
Loam = soil with an even mixture of the three
Influences how easy it is to cultivate and let air and water travel through the soil
Soil structure = a measure of soil’s “clumpiness”
Large clumps can discourage plant roots
Repeated tilling compacts soil, decreasing its water-absorbing capabilities
Plowpan = a hard layer resulting from repeated plowing that resists water infiltration and root
penetration
Soil pH = influences a soil’s ability to support plant growth
Soils that are too acidic or basic can kill plants
Cation exchange = process that allows plants to gain nutrients
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Negatively charged soils hold cations (positively charged ions) of calcium, magnesium, and
potassium
Cation exchange capacity = a soil’s ability to hold cations, preventing them from leaching,
thereby increasing their availability to plants
A useful measure of soil fertility
Greatest in fine soils
Swidden agriculture = cultivation of a plot for a few years and then letting it regrow into forest
Deposition = the arrival of eroded material at its new location
Desertification = a loss of more than 10% productivity
Conservation districts = districts operate with federal direction, authorization, and funding, but
are organized by the states
Crop Rotation = alternating the crops grown field from one season or year to the next,
Cover crops protect soil when main crops aren’t planted
Wheat or corn and soybeans
Contour Farming = plowing furrows sideways across a hillside, perpendicular to its slope, to prevent rills and gullies
Terracing = level platforms are cut into steep hillsides, sometimes with raised edges
A “staircase” to contain water
Intercropping = planting different types of crops in alternating bands or other spatially mixed
arrangements
• Shelterbelts or Windbreaks = rows of trees or other tall, perennial plants that are planted
along the edges of fields to slow the wind
- Alley cropping = shelterbelts + intercropping
• Reduced Tillage = furrows are cut in the soil, a seed is dropped in and the furrow isclosed
- No-till farming disturbs the soil even less
• Irrigation = Artificially providing water to support agriculture
- Unproductive regions become farmland
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• Waterlogging = over-irrigated soils
- Water suffocates roots
• Salinization = the buildup of salts in surface soil layers
- Worse in arid areas
- Drip irrigation targets water directly to plants
• Fertilizer = substances that contain essential nutrients
• Inorganic fertilizers = mined or synthetically manufactured mineral supplements
• Organic fertilizers = the remains or wastes of organisms
- manure, crop residues, fresh vegetation
- Compost = produced when decomposers break down organic matter
• Overgrazing = too many animals eat too much of the plant cover
• Clear-cutting = the removal of all trees from an area at once
Chapter 10
• transgenes (genes from one species used to enhance another)• Food security = the guarantee of adequate and reliable food supply to all people at all
times
• Undernourishment = people receive less than 90% of their daily caloric needs
- Mainly from economic reasons in developing countries
- 31 million Americans are food insecure
• Overnutrition = receiving too many calories
- In the U.S., 25% of adults are obese
- Worldwide, more than 300 million people are obese
• Malnutrition = a shortage of nutrients the body needs
• Kwashiorkor = diets lacking protein or essential amino acids
• Occurs when children stop breast-feeding
• Bloated stomach, mental and physical disabilities
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• Marasmus = protein deficiency and insufficient calories
• Wasting or shriveling of the body
• Monoculture = a large expanse of a single crop
• Pest = any organism that damages valuable crops
• Weed = any plant that competes with crops
• Pesticides = poisons that target pest organisms
• Insecticides = target insects
• Herbicides = target plants
• Fungicides = target fungi
- Evolutionary arms race: chemists increase chemical toxicity to compete with
resistant pests
- Biological control (Biocontrol) = uses a pest’s natural predators to control the pest
- Reduces pest populations without chemicals
- Cactus moths control prickly pear
- Bacillus thuringiensis (Bt) = soil bacteria that kills many pests
• Pollination = male plant sex cells fertilize female sex cells
• Genetic engineering = laboratory manipulation of genetic material
• Genetically modified organisms = organisms that have been genetically engineered by
• Recombinant DNA = DNA created from multiple organisms
• Biotechnology = the material application of biological science to create products derived
from organisms
• Transgenic organism = an organism that contains DNA from another species
• Transgenes = the genes that have moved between organisms
• precautionary principle = don’t do any new action until it’s understood
• Seed banks = institutions that preserve seed types as a kind of living museum of genetic
diversity
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• Feedlots (factory farms) = also called Concentrated Animal Feeding Operations
(CAFOs)
• Aquaculture = raising aquatic organisms for food in a controlled environment
• Industrial agriculture may seem necessary, but less-intensive agricultural methods may be
better in the long run
• Sustainable agriculture = does not deplete soil, pollute water, or decrease genetic
diversity
• Low-input agriculture = uses smaller amounts of pesticide, fertilizers, growth hormones,
water, and fossil fuel energy than industrial agriculture
• Organic agriculture = Uses no synthetic fertilizers, insecticides, fungicides, or
herbicides
• Community gardens = areas where residents can grow their own food
• Community-supported agriculture = consumers pay farmers in advance for a share of their yield
Chapter 11
• Biodiversity – sum total of all organisms in an area
- Split into three specific levels:
- Species diversity
- Genetic diversity
- Ecosystem diversity
• Species Diversity = the number or variety of species in the world or in a particular region
- Richness = the number of species
- Evenness or relative abundance = extent to which numbers of individuals of
different species are equal or skewed
• Taxonomists = scientists who classify species
- Physical appearance and genetics determines a species
- Genera = related species are grouped together
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- Families = groups of genera
• Subspecies = populations of species that occur in different areas and differ slightly fromeach other
- Inbreeding depression = genetically similar parents mate and produce inferior offspring
• Ecosystem diversity = the number and variety of ecosystems
• Latitudinal gradient = species richness increases towards the equator
• Extinction = occurs when the last member of a species dies and the species ceases toexist
• Extirpation = the disappearance of a particular population from a given area, but not theentire species globally
• The Red List = an updated list of species facing high risks of extinctions
• Biophilia = connections that humans subconsciously seek with life
- Our affinity for parks and wildlife
- Keeping of pets
- High value of real estate with views of natural lands
• Nature deficit disorder = alienation from the natural environment
- May be behind the emotional and physical problems of the young
• Conservation biology = devoted to understanding the factors that influence the loss,
protection, and restoration of biodiversity
• Conservation geneticists = study genetic attributes of organisms to infer the status of their population
• Minimum viable population = how small a population can become before it runs into problems
• Metapopulations = a network of subpopulations- Small populations are most vulnerable to extinction and need special attention
- Equilibrium theory of island biogeography = explains how species come to bedistributed among oceanic islands
• Captive breeding – individuals are bred and raised with the intent of reintroducing them
into the wild
• Cloning – a technique to create more individuals and save species from extinction
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- Protecting the habitat of these umbrella species helps protect less-charismatic
animals that would not have generated public interest
• Flagship species – large and charismatic species used as spearheads for biodiversity
conservation
• Biodiversity hotspots – prioritizes regions most important globally for biodiversity
- Support a great number of endemic species = species found nowhere else in theworld
• Community-based conservation = conservation biologists actively engage local peoplein protecting land and wildlife
• Debt-for-nature swap = a conservation organization pays off a portion of a developingcountry’s international debt
• Conservation concession = conservation organizations pay nations to conserve, and notsell, resources
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