Exam 2

a large flightless bird native to Mauritius; is now extinct due to human introduction of rats to its habitat
Passenger Pigeon
once the most abundant bird in North America; went from 5 billion to 0 in five years due to human hunting
Rachel Carson
author of Silent Spring
Silent Spring
classic conservation book on the results of chemical warfare on the environment
theory that states that simplification of ecosystems may ultimately undermine their ability to function at all; controversial theory
exotic species
a species not native to the area in which it lives; can cause extinction of natural species in the area

examples: Argentine fire ant, Zebra mussels, Nutria

land conversion
turning natural habitats into farms, shopping malls, suburbs, amusement parks, etc.; one of the biggest problems facing most species today
habitat loss
when a habitat becomes unlivable for its native species; single greatest threat to wildlife
when the original, unbroken habitat exists only in fragments; almost as deadly as complete loss of habitat
deforestation (tropic vs. temperate pattern)
loss of forest habitat

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tropics: large areas cleared at once over a short period of time

temperate: small areas cleared over a long period of time

–> same end result

theory of island biogeography
the equilibrium number of species on an island will be a balance between the opposing forces of immigration and extinction
draw the two graphs demonstrating island biogeography
dispersal ability
how well a species is able to travel to far places; ex. birds good, snails bad
waif dispersal
species finding its way to a new place by hitching a ride with something else; ex. a squirrel on a log
rate of immigration
the pace at which new species arrive on an island; depends on distance from the island to the mainland and dispersal ability of the colonizers
rate of extinction
how fast species on an island go extinct; increases as the number of species on the island increases
equilibrium number of species
a balance between the rate of immigration and the rate of extinction
small volcanic island in Dutch East Indies; in 1883 blew apart in volcanic eruption; provided good study for theory of island biogeography and confirmed the model’s predictions
neotropical migrant
birds that winter in Central and South America and spend the rest of the year in North America; rapidly declining species due to fragmentation of habitat
conservation biology
specific subfield of biology that studies the preservation of biodiversity; did not officially become a science until 1980s
game species
species that can be hunted for commercial gain; ex. deer or ducks
non-game species
species that have no commercial value when hunted
resource management
conserving resources that can be exploited for commercial gain; ex. meat, fur, timber, minerals
consumptive use
using resources and wildlife for consumption; the primary concern of traditional resource management
non-consumptive use
value of wildlife other than consumption; ex. hiking, birdwatching, ecotourism
number of different species in a given area
alpha diversity
diversity of species in a local habitat type; ex. local wetland or forest
beta diversity
local biodiversity across several different types of habitats
gamma diversity
regional biodiversity over a large area with many types of habitats
genetic diversity
total number of genes that are characteristic of a species or group of species
species diversity
determined by species richness, species evenness, and species dominance
species richness
total number of species
species evenness
relative abundance of species across different habitats or regions
species dominance
which species are most abundant in a particular ecosystem
ecological diversity
number of trophic levels, number of available niches, and the complexity of the food web
the study of the geographic distribution of species
area-sensitive species
species that need a minimum amount of space to survive or reproduce
habitat heterogeneity
the level of diversity and complexity in a habitat; niches are lost as habitat heterogeneity is lost
biotic interactions
interaction between living things; ex. predator/prey, plant/pollinator
secondary extinctions
when one species becomes extinct after its biotic interaction with another species is disrupted due to extinction of that species
edge effect
algebraic consequence of decreasing area –> smaller circles have more edge relative to interior; shifts balance of biodiversity to edge-favoring species; means increased competition, parasitism, and predation

–> we should try to minimize amount of edge with circular tracts with smooth edges

interior edge
any space cleared in the interior of a park or preserve; ex. roads, parking lots,buildings; should be avoided
brood parasites that are taking over Louisiana due to increased edge effect
brood parasitism
laying eggs in another birds nest to force that bird to raise the young
Bubba effect
how far “Bubba” (human) is willing to go into the wilderness; part of edge effect due to Bubba, from obscure roads for loggers
natural areas that can be safely used by plants or animals to move from one habitat fragment to another; should be 100-300 meters wide
view that sees populations as a matrix of scattered but interacting local populations
winking patches
habitats where species flicker on and off due to immigration and extinction
rescue effect
small populations can be maintained in smaller areas as long as the population can be rescued by immigration from other patches
Yellowstone to Yukon Conservation Initiative: a corridor that aims to connect the Yukon wilderness with the southern Rocky Mountains; could ensure survival of the Grizzly bear
minimum viable population: minimum population size needed to maintain genetic viability of a population
50/500 rule
ecological disagreement on how many healthy individuals needed for MVP; animal breeders say 50, population genetics models predict 500
International Species Information System: an online database (studbook) used by zoos to decide which animals to exchange for mating; helps maximize outcrossing and minimize inbreeding
Audubon Center for Research on Endangered Species (West Bank): among the world’s leading institutes in the preservation of endangered species
Thomas Malthus
scholar who wrote Essay on the Principle of Population which introduced the theories of the population principle and the struggle for existence
population principle
the human population will grow “geometrically” (exponentially) but resources will only increase arithmetically
struggle for existence
because population will increase geometrically and resources increase only arithmetically, there will be a growing gap between too many people and too few resources; this will lead to widespread starvation and suffering; Malthus says, “part of divine plan”
Poor Laws
British welfare system dating back to Elizabethan times; Malthusian theory reduced welfare with Poor Law Amendment of 1834
replacement rate: number of offspring left behind by each adult female
seasonal breeders
species that have an annual breeding season; ex. deer, birds, plants
geometric model
population growth model that assumes 1) seasonal breeding and 2) no limits to growth and predicts populations will grow geometrically (exponential curve, J-shaped, stepwise); ex. White Ibis in Louisiana
instantaneous growth rate: intrinsic rate of natural increase
exponential model
population growth model that assumes 1) continuous breeding and 2) no limits to growth and predicts populations will grow exponentially (exponential curve, J-shaped, smooth)
birth rate
death rate
continuous breeders
species that have no specific breeding season; ex. humans, bacteria
carrying capacity: limits to growth in a given environment
logistic model
population growth model that assumes 1) continuous breeding and 2) limits to growth and predicts populations will grow exponentially and then level off at K (exponential curve, S-shaped, smooth); ex. humans
too many people, not enough resources; biggest problem humankind faces today
lifestyle in early human history; led to low birth rates –> very steady population levels
life expectancy
how long the average human lives; has increased exponentially with technological progress
the global sum of all ecosystems; massive human population growth will have tremendously devastating effect on the biosphere
fertility rate
number of children a female has over her lifetime; <2 in developed countries; >2 in LDCs
demographic transition
the shift from high birth rate and high death rate to low birth rate and low death rate; critical stage in a nation’s growth that usually marks the change to industrial society
age structure of a population
number of individuals in each age class; major problem in LDCs –> 37% of population under 15
net population growth: how much a population grows in a year
zero NPG
zero net population growth: parents replace themselves with no extra children; the longer it takes to reach zero NPG, the more devastating it is to Earth and the human population
Cairo Conference
1994 UN Conference on Population and Development: a milestone toward global population control in which almost* all nations reached an agreement on international population control

*not US

human footprint
represents the net effect we have as individuals, or as a species, on local and global systems; we have a very large footprint –> we use resources and damage the environment out of all proportion to our actual numbers
swidden agriculture
slash and burn to created fields
soil degradation
soil that is ruined and cannot be used for agriculture; causes: deforestation, overgrazing, overcultivation; led to the collapse of Mayan civilization
animals that feed on detritus (dead and decaying matter); soil ecology depends on detritivores to recycle nutrients back to the soil
leftover small organic particles in the soil; forms the very top layer of soil, the “O horizon”
soil structure
the physical characteristics of the soil; ex. particle size, pore spaces, how the grains clump together, etc.
soil horizons
specific layers in the soil which differ from the layers above and below it
soil profile
all the layers visible when you take a section through the soil (the sequence of layers)
O horizon
layer of soil made up of humus; top layer
A horizon
the level below the O horizon; aka the topsoil; contains some humus
A horizon; level just below the humus (O horizon)
E horizon
layer under A horizon; lighter; very little humus
B horizon
layer under E horizon; aka subsoil; leached materials accumulate in B horizon –> give it red or yellow color
B horizon; layer under E horizon
C horizon
lowest soil layer; under B horizon; basic mineral soil with no organic matter (parent material)
order of soil horizons
OAEBC: Only Arkansas Exudes Beautiful Car rides.
parent material
organic matter in soil; the starting point in the formation of new soil; can form through volcanic deposition, glacial deposition, or natural weathering of rock
no-till farming
farming that does not churn up the topsoil, exposing it to direct erosion; relies on special plowing disks to turn topsoil back under
healthy soils turned into sterile soils; caused by deforestation, overgrazing, and overcultivation
an increase in soil salinity; caused by irrigated agriculture; another cause of soil degredation
Dust Bowl
phenomenon in the 1930s where most of the American Midwest dried up and blew away
rows of trees planted to block wind and slow down erosion; federal effort undertaken after the Dust Bowl to restore the land
counter plowing
method of plowing that helped hold remaining topsoil in place; federal effort undertaken to restore the land after the Dust Bowl
traditional fishing grounds
tragedy of the commons
destruction of property that belongs to everyone by a handful of greedy individuals who over-exploit and destroy it
factory fleet
large-scale commercial fishing fleets
a method of fishing that uses huge weighted nets that scrape up the bottom of the sea, totally destroying the fragile marine ecology
land that cattle graze on
pasture land
land on which crops are grown to feed cattle e.g. corn, hay, etc.
land on which food is grown to feed people; 3 most important crops: rice, wheat, and corn
per capita harvest
crop harvest per number of people; in excess in developed countries; struggling in LDCs
Green Revolution
technological innovation that revolutionized global agriculture; due to Norman Borlaug’s dwarf hybrid strain of wheat
territorial limit
how far offshore a country claims its domain
Economic Exclusion Zone
a country’s offshore domain, in which only that country has the right to fish; 200 miles offshore
fish farming
dwarf hybrid strains
hybrid strain of a plant that enables it to grow closer to the ground so that more of its energy is invested in the head of the plant, not the stalk; leads to huge gains in production of a crop
amount of production of fixed carbon in photosynthesis (carbon incorporated into glucose molecules)
per capita area of grain harvest
how much grain we are harvesting per person; consistent downward trend in all nations
condition that results from an unbalanced diet; especially high in LDCs; 2-edged sword: children lose their health and countries lose future productivity –> vicious cycle of poverty, starvation, and ignorance
oil crops
crops grown for fuel e.g. soybeans and types of corn
luxury crops
crops not necessary for human survival e.g. cotton, coffee
watering land to make it suitable for farming; more and more farmland needs heavy irrigation
water table
top level of underground water pools; dropping rapidly all over the world due to increase in farming
underground sources of water; quickly becoming drained to irrigate farmland
recharge rate
the time an aquifer needs to recharge; can’t keep pace with how quickly we are using them
the amount of water it would take to fill an acre of land to one foot deep
drip irrigation
more efficient system of irrigation that drips just the right amount of water on each plant