Module 1: Ecology: The Study of Our World (VOCAB) Flashcards
ecology
Study of how populations interact with one another and with their nonliving environment.
interdependence
The survival of species is dependent on other living organisms and nonliving components.
ecological model
Model that represents or describes components of an ecological system.
biotic
LIVING components of a system.
abiotic
NONLIVING components of a system (i.e., temperature, water, inorganic nutrients, and organic compounds found in the soil).
niche
The role, or way of life of a species within its environment.
generalist
A species that is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources (i.e., a heterotroph with a varied diet).
specialist
A species that can thrive only in a narrow range of environmental conditions or has a limited diet (i.e., the koala, which subsists almost entirely on eucalyptus leaves).
biosphere
The layer around the Earth within which all living organisms live.
lithosphere
The rock layer around the surface of the Earth.
autotroph
These are organisms that acquire their food from an abiotic source. Most autotrophs are photosynthetic organisms although there are a few that use inorganic compounds as a source of energy.
heterotroph
These are organisms that acquire their food (energy) from an organic source. Organisms that feed from living organisms are often referred to as consumers, while organisms that feed from dead organic matter are often referred to as decomposers or reducers.
population ecology
The science that studies the processes occurring within populations.
population
Group of organisms of the same species that live in the same area and interbreed.
demographics
Statistics that describe a population’s traits.
population size
Total number of individuals in a population.
plot sampling
Method of estimating population size of organisms that do not move much by making counts in small plots and extrapolating from this to the number in the larger area.
mark-recapture sampling
Method of estimating population size of mobile animals by marking individuals, releasing them, then checking the proportion of marks among individuals later recaptured.
population density
Number of individuals per unit area or volume.
population distribution
Describes whether individuals are clumped, uniformly dispersed, or randomly dispersed in an area.
clumped distribution
Members of a population are closer to one another than would be predicted by chance alone. Most populations have a clumped distribution. (i.e., A patchy distribution of resources encourages clumping, as when hippopotamuses gather in muddy river shallows.)
near-uniform distribution
Competition for limited resources can produce a near-uniform distribution, with individuals more evenly spaced than would be expected by chance. (i.e., Creosote bushes in deserts of the American Southwest grow in this pattern. Competition for water among the root systems keeps the plants from growing in close proximity.)
random distribution
Members of a population are distributed randomly when resources are uniformly available, and proximity to others neither benefits nor harms individuals. (i.e., When wind-dispersed dandelion seeds land on the uniform environment of a suburban lawn, dandelion plants grow in a random pattern.)
age structure
Of a population, the number of individuals in each of several age categories (pre-reproductive, reproductive, or post-reproductive).
reproductive base
Of a population, all individuals who are of pre-reproductive or reproductive ages.
immigration
Movement of individuals INTO a population.
emigration
Movement of individuals OUT of a population.
zero population growth
Interval in which the number of births = the number of deaths.
per capita growth rate
For some interval, the added number of individuals divided by the initial population size.
∙ [b − d = r]
∙ b = per capita birth rate
∙ d = per capita death rate
∙ r = per capita growth rate
exponential growth model
Model of unlimited population growth. The population grows by a fixed percentage in each successive time interval; the size of each increase is determined by the current population size.
** population growth plots out as a J-shaped curve **
∙ [N × r = G]
∙ N = number of individuals
∙ r = per capita growth rate
∙ G = population growth per unit time
biotic potential
Maximum possible population growth rate under optimal conditions.
density-dependent limiting factor
Factor that increasingly limits population growth as population density increases. Density-dependent limiting factors include competition, predation, parasitism, and disease.
intraspecific competition
Competition among members of the same species.
logistic growth
Density-dependent limiting factors cause population growth to slow as population size increases.
** population growth plots out as a S-shaped curve **
∙ [G = (r)max × N × (K − N) / K]
∙ G = population growth per unit time
∙ (r)max = maximum per capita population growth rate
∙ N = number of individuals
∙ K = carrying capacity
∙ (K − N) / K = proportion of resources not yet used
carrying capacity (K)
Maximum number of individuals of a species that an environment can sustain.
density-independent limiting factor
Factor that limits population growth to the same degree regardless of population density. Natural disasters, weather-related events, or human-caused events can decrease population size (these events are density-independent because crowding does not influence the likelihood of their occurrence or the magnitude of their effect).
life history
Schedule of how resources are allocated to growth, survival, and reproduction over a lifetime.
cohort
Group of individuals born during the same time interval.
survivorship curve
Graph showing the decline in numbers of a cohort over time. Ecologists have described three generalized types of curves: type I, type II, and type III.
type I curve
A type I curve is CONVEX, indicating survivorship is high until late in life. Humans and other large mammals that produce one or two young and care for them show this pattern.
type II curve
A DIAGONAL type II curve indicates that the death rate of the population does not vary much with age. In lizards, small mammals, and large birds, old individuals are about as likely to die of disease or predation as young ones.
type III curve
A type III curve is CONCAVE, indicating that the death rate for a population peaks early in life. Marine animals that release eggs into water have this type of curve, as do plants that release enormous numbers of tiny seeds.
r-selection
Selection that favors traits that allow their bearers to produce the most offspring the most quickly (short generation time and small body size).
** maximize QUANTITY **
K-selection
Selection favoring traits that provide a competitive advantage when population size is near carrying capacity (long generation time and large body size).
** maximize QUALITY **
total fertility rate
Average number of children the women of a population bear over the course of a lifetime.
replacement fertility rate
Fertility rate at which each woman has, on average, one daughter who survives to reproductive age.
demographic transition model
Model describing changes in birth and death rates that occur as a region becomes industrialized.
ecological footprint
Area of Earth’s surface required to sustainably support a particular level of development and consumption. It includes the amount of area required to grow crops, graze animals, produce forest products, catch fish, hold buildings, and take up any carbon emitted by burning fossil fuels.
habitat
Type of environment in which a species typically lives.
species richness
Of a community, the number of species.
species evenness
Of a community, the relative abundance of species.
commensalism
Species interaction that benefits one species and neither helps nor harms the other.
symbiosis
One species lives in or on another in a commensal, mutualistic, or parasitic relationship.
equilibrium model of island biogeography
Model that predicts the number of species on an island based on the island’s area and distance from the mainland.
distance effect
Islands close to a mainland have more species than those farther away.
area effect
Larger islands have more species than small ones.
mutualism
Species interaction that benefits both participants.
interspecific competition
Competition between two species.
ecological niche
The resources and environmental conditions that a species requires.
competitive exclusion
Process whereby two species compete for a limiting resource, and one drives the other to local extinction.
resource partitioning
Species adapt to access different portions of a limited resource; allows species with similar needs to coexist.
character displacement
Outcome of competition between two species; similar traits that result in competition become dissimilar.
predation
An interspecific interaction in which one species (the predator) captures, kills, and eats another (the prey).
parasitism
Relationship in which one species withdraws nutrients from another species, without immediately killing it.
brood parasitism
One egg-laying species benefits by having another raise its offspring.
parasitoid
An insect that lays eggs in another insect, and whose young devour their host from the inside.
biological pest control
Use of a pest’s natural enemies to reduce its numbers.
primary succession
A new community colonizes an area where there is no soil.
pioneer species
Species that can colonize a new habitat.
secondary succession
A new community develops in a disturbed site where the soil that supported a previous community remains.
intermediate disturbance hypothesis
Species richness is greatest in communities where disturbances are moderate in their intensity or frequency.
indicator species
A species that is especially sensitive to disturbance and can be monitored to assess the health of a habitat.
keystone species
A species that has a disproportionately large effect on community structure.
exotic species
A species that evolved in one community and later became established in a different one.
endemic species
A species found in the region where it evolved and nowhere else.
ecosystem
A community interacting with its environment.
primary producer
In an ecosystem, an organism that captures energy from an inorganic source and stores it as biomass; first trophic level.
consumer
Organism that gets energy and nutrients by feeding on tissues, wastes, or remains of other organisms; a heterotroph.
detritivore
Consumer that feeds on small bits of organic material.
decomposer
Consumer that feeds on biological remains and breaks down into its inorganic subunits.
trophic level
Position of an organism in a food chain.
food chain
Description of who eats whom in one path of energy flow in an ecosystem.
food web
Set of cross-connecting food chains.
grazing food web
Food web in which most energy is transferred from producers to grazers (herbivores).
detrital food web
Food web in which most energy is transferred directly from producers to detritivores.
primary production
Rate at which an ecosystem’s producers capture and store energy.
biomass pyramid
Diagram that depicts the biomass (dry weight) in each of an ecosystem’s trophic levels.
energy pyramid
Diagram that depicts the energy that enters each of an ecosystem’s trophic levels. Lowest tier of the pyramid, representing primary producers, is always the largest.
biogeochemical cycle
Movement of an element or compound among environmental reservoirs and into and out of food webs.
atmospheric cycle
Biogeochemical cycle that includes an atmospheric reservoir.
sedimentary cycle
Biogeochemical cycle that involves rocks and waters, but not the atmosphere.
water cycle
Biogeochemical cycle in which water among the atmosphere, land, and waters, and into and out of food webs.
watershed
Land area that drains into a particular stream or river.
groundwater
Soil water and water in aquifers.
soil water
Water between soil particles.
aquifer
Porous rock layer that holds some groundwater.
runoff
Water that flows over soil into streams.
carbon cycle
Movement of carbon, mainly between the oceans, atmosphere, and living organisms.
nitrogen cycle
Movement of nitrogen among the atmosphere, soil, and water, and into and out of food webs.
nitrogen fixation
Incorporation of nitrogen from nitrogen gas into ammonia.
ammonification
Breakdown of nitrogen-containing organic material resulting in the release of ammonia and ammonium ions.
nitrification
Conversion of ammonium to nitrates.
denitrification
Conversion of nitrates or nitrites to gaseous forms of nitrogen.
phosphorus cycle
Movement of phosphorus among Earth’s rocks and waters and into and out of food webs.
biosphere
All regions of Earth that can support life.
climate
Average weather conditions in a region over a long period.
monsoon
Wind that reverses direction seasonally.
rain shadow
Dry region downwind of a coastal mountain range.
biome
Group of regions that may be widely separated but share a characteristic climate, soil composition, and dominant vegetation.
temperate deciduous forest
Northern Hemisphere biome in which the main plants are broadleaf trees that lose their leaves in autumn and become dormant during cold winters.
tropical rain forest
Highly productive and species-rich biome in which year-round rains and warmth support continuous growth of evergreen broadleaf trees.
boreal forest
Extensive high-latitude forest of the Norther Hemisphere; conifers are the predominant vegetation.
temperate grassland
Temperate biome in the interior of continents; perennial grasses and other nonwoody plants adapted to grazing and fire predominate.
savanna
Tropical biome dominated by grasses with a few scattered shrubs and trees.
dry shrubland
Biome dominated by a diverse array of fire-adapted shrubs; occurs in regions with cool, wet winters and a dry summer.
desert
Biome with little rain and low humidity; plants that have water-storing and water-conserving adaptations predominate.
spring overturn
In temperate zone lakes, a downward movement of oxygenated surface water and an upward movement of nutrient-rich water in spring.
thermocline
Thermal stratification in a large body of water, a cool midlayer stops vertical mixing between warm surface water above it and cold water below it.
fall overturn
During the fall, waters of a temperate zone mix. Upper, oxygenated water cools, gets dense, and sinks; nutrient-rich water from the bottom moves up.
estuary
Highly productive ecosystem where nutrient-rich water from a river mixes with seawater.
coral reef
Highly diverse marine ecosystem centered around reefs built by living corals that secrete calcium carbonate.
pelagic province
The ocean’s waters.
benthic province
The ocean’s sediments and rocks.
seamount
An undersea mountain.
hydrothermal vent
Rocky, underwater opening where mineral-rich water heated by geothermal energy streams out.
