Environmental Mid-Term Notes

8/3/2019 Environmental Mid-Term Notes

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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



- 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



• 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



• 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



• 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



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



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



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



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



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



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



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



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



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



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



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



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



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



- 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



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



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



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



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



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



• 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



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



• 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



• 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



• 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



- 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



- 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



Documents

Environmental Mid-Term Notes