4.G: Unit 4 - Glossary

Unit 4.2

abiotic

nonliving components of the environment

age structure

proportion of population members at specific age ranges

allelopathy

a type of chemical competition performed by plants in the soil

biotic

living components of the environment

biotic potential (r_max)

maximal potential growth rate of a species

birth rate (B)

number of births within a population at a specific point in time

camera traps

useful for studying rare and/or nocturnal animals to estimate density

carrying capacity (K)

number of individuals of a species that can be supported by the limited resources of a habitat

clumped distribution

individuals are clustered together due to behavior, resources, or limited dispersion of offspring from the parent

community

the different species within an area, typically a three-dimensional space, and the interactions within and among these species

complete census

counting each individual present within the population

conspecifics

organisms that are all members of the same species

constraints

limits can be physical, developmental, or historical, and they are imposed by the existing traits of the organism

death rate (D)

number of deaths within a population at a specific point in time

demographic-based population model

modern model of population dynamics incorporating many features of the r- and K-selection theory

demography

statistical study of changes in populations over time

density-dependent regulation

regulation of population that is influenced by population density, such as crowding effects; usually involves biotic factors

density-independent regulation

regulation of populations by factors that operate independent of population density, such as forest fires and volcanic eruptions; usually involves abiotic factors

dispersal

long-range movement between populations

ecological footprint

combined impact of resource utilization and waste generation of an individual

ecology

study of interactions between living things and their environment

ecosystem

community of living organisms and their interactions with their abiotic environment

ecosystem ecology

studies how nutrients and energy are stored and how they move among organisms and the surrounding atmosphere, soil, and water

energy budget

allocation of energy resources for body maintenance, reproduction, and parental care

exponential growth

accelerating growth pattern seen in species under conditions where resources are not limiting

fecundity

potential reproductive capacity of an individual

fundamental geographic range

the area a species occupies in which environmental conditions are favorable, without restriction from barriers to disperse or colonize

generalists

species that can thrive in a wide variety of environmental conditions

heterospecifics

individuals that are members of different species

home range

an area utilized and perhaps defended by a single organism

instantaneous growth rate

instant-specific measurement of growth based on calculus

intraspecific competition

competition between members of the same species

intrinsic rate of increase

difference between birth and death rates; potential for reproduction

iteroparity

life history strategy characterized by multiple reproductive events during the lifetime of a species

J-shaped growth curve

shape of an exponential growth curve

K-selected species

species suited to stable environments that produce a few, relatively large offspring and provide parental care

life cycle

specific sequence in the development of the life of an individual as defined by its species

life expectancy

the length of time individuals remain in the population

life history

inherited pattern of resource allocation under the influence of natural selection and other evolutionary forces

life table

table showing the life expectancy of a population member based on its age

line or point transect

distance sampling methods to estimate density or abundance; frequently used for animals

logistic growth

leveling off of exponential growth due to limiting resources

mark and recapture

technique used to determine population size in mobile organisms

mortality rate

proportion of the population surviving to the beginning of an age interval that dies during the age interval

niche

how an organism or population responds to the distribution of environmental resources (abiotic components of the environment) and predators, pathogens, and competitors (biotic components of the environment)

occupancy

whether a given species or member of a population occurs in a habitat patch, fragment, or area

ontogeny

timing and pattern of life cycle events of a species

optimality

a life history strategy that allows the highest level of fitness possible

organismal ecology

studies adaptations that enable individuals to live in specific habitats

population

a group of interbreeding organisms that are members of the same species living in the same area at the same time

population density

number of population members divided by the area or volume being measured

population distribution

geographic area where a particular population of a species occurs

population dynamics

changes in population size over time and the processes that cause them to occur

population ecology

studies the number of individuals in an area and how and why population size changes over time

population growth rate

number of organisms added in each reproductive generation

population index

data that correlates with abundance of individuals

population size (N)

number of population members in a habitat at the same time

quadrat

square made of various materials used to determine population size and density in slow moving or stationary organisms

r-selected species

species suited to changing environments that produce many offspring and provide little or no parental care

random distribution

individuals are neither uniform nor clumped but rather are randomly dispersed with respect to one another

realized geographic range

a more narrow subset of its larger fundamental geographic range due to limitations from abiotic or biotic interactions

relative abundance

individuals in a given area of space per the total number of all individuals of all species

reproductive effort

energy towards producing offspring

restricted range

a species in which the range is so small, there is basically a single population; the species' population distribution and geographic range are essentially the same

S-shaped growth curve

shape of a logistic growth curve

semelparity

life history strategy characterized by a single reproductive event followed by death

somatic effort

energy towards growth and maintenance of the body

specialists

species that can thrive in a specialized subset of environmental conditions

species

a group of organisms capable of interbreeding

species dispersion pattern

(also, species distribution pattern) spatial location of individuals of a given species within a habitat at a particular point in time compared to one another

species distribution pattern

(also, species dispersion pattern) spatial location of individuals of a given species within a habitat at a particular point in time compared to one another

survivorship curve

graph of the number of surviving population members versus the relative age of the member

Type I survivorship curve

high percentage of offspring survive their early and middle years—death occurs predominantly in older individuals

Type II survivorship curve

individuals die more or less equally at each age

Type III survivorship curve

very few of these organisms survive their younger years; however, those that make it to old age are more likely to survive for a relatively long period of time

uniform distribution

individuals are equidistant from each other, due to competition or territorialism

zero population growth

steady population size where birth rates and death rates are equal

Unit 4.3

alternative stable states

various stable end-points for secondary succession

ambush predation

predators sit and wait for prey

aposematic coloration

coloration as a way of warning predators that they are not good to eat

Batesian mimicry

a harmless species imitates the warning coloration of a harmful one

biodiversity

describes a community’s biological complexity

browsing

90% of an herbivore's diet is tree leaves and twigs

camouflage

defense strategy of avoiding detection by blending in with the background

chain of infection

the chain of events involves several steps including the infectious agent, reservoir, entering a susceptible host, exit, and transmission to new hosts

chemical defense

discourage animal predation and herbivory by generating toxins or unpalatable chemicals

climax community

final stage of succession, where a stable community is formed by a characteristic assortment of plant and animal species

commensalism

relationship between species wherein one species benefits from the close, prolonged interaction, while the other species neither benefits nor is harmed

community dynamics

how communities change over time

community structure

the types and numbers of species present in a community

competitive exclusion principle

no two species within a habitat can coexist when they compete for the same resources at the same place and time

disturbance

changes to environmental conditions due to abiotic or biotic factors

equilibrium

steady state of an ecosystem where all organisms are in balance with their environment and each other

evolutionary arms race

a cycle of adaptations and counter-adaptations between predators and prey

foundation species

species which often forms the major structural portion of the habitat

grazing

90% of an herbivore's diet is grass

herbivory

a form of consumption in which an organism principally eats autotrophs such as plants, algae and photosynthesizing bacteria

host

organism a parasite lives on

infection

the invasion of an organism's body tissues by pathogens

infectious disease (also, transmissible or communicable disease)

an illness resulting from an infection

interspecific competition

competition between individuals of different species

intermediate disturbance hypothesis (IDH)

local species diversity is maximized when ecological disturbances are neither too rare nor too frequent

invasive speces

non-native organisms that, when introduced to an area out of their native range, threaten the ecosystem balance of that habitat

island biogeography

study of life on island chains and how their geography interacts with the diversity of species found there

keystone species

species whose presence is key to maintaining biodiversity in an ecosystem and to upholding an ecological community’s structure

mechanical defense

discourage animal predation and herbivory by causing physical pain to the predator/herbivore or by physically preventing the predator/herbivore from being able to eat the prey

mimicry

one species imitates the adaptations of another

mixed-feeding

a combination of browsing and grazing by herbivores

Müllerian mimicry

multiple species share the same warning coloration and all of them have defenses

mutualism

symbiotic relationship between two species where both species benefit

parasite

organism that uses resources from another species, the host

parasitism

symtbiotic relationship between two species where one species benefits and the other species has significant costs

parasitoid

an organism whose feeding leads to the death of its host; defined as different than predator due to only one prey over its lifetime

pathogens

disease-causing agents

pioneer (early successional) species

first species to appear in primary and secondary succession

predation

where one organism (predator) kills and eats another (prey)

predator

animal species that hunt and are carnivores or “flesh eaters”; a predator has many prey over its lifetime

primary consumer

trophic level that obtains its energy from the primary producers of an ecosystem

primary succession

succession on newly exposed substrate or soil with no life currently present

pursuit predation

predators actively search for and/or pursue prey

secondary succession

succession in response to environmental disturbances that move a community away from its equilibrium

species diversity

the number of species occupying the same habitat and their relative abundance

species interactions

an effect that a pair of organisms living together in a community have on each other

species richness

number of different species in a community

succession

the process of change in the species structure of an ecological community over time

Unit 4.4

aboveground biomass

total mass of aboveground living plants per area

abyssal zone

deepest part of the ocean at depths of 4000 m or greater

acid rain

corrosive rain caused by rainwater falling to the ground through sulfur dioxide gas, turning it into weak sulfuric acid; can damage structures and ecosystems

algal bloom

rapid increase of algae in an aquatic system

analytical model

ecosystem model that is created with mathematical formulas to predict the effects of environmental disturbances on ecosystem structure and dynamics

apex consumer

organism at the top of the food chain

aphotic zone

part of the ocean where no light penetrates

Arctic tundra

very cold, long winters and extremely short, cold summers with very low precipitation; vegetation dominated by small, low-growing shrubs, lichens, and mo

sses.

assimilation

biomass consumed and assimilated from the previous trophic level after accounting for the energy lost due to incomplete ingestion of food, energy used for respiration, and energy lost as waste

benthic realm

(also, benthic zone) part of the ocean that extends along the ocean bottom from the shoreline to the deepest parts of the ocean floor

bioaccumulate

the ability of a substance to remain within an organism and not be metabolized

biogeochemical cycle

cycling of mineral nutrients through ecosystems

biogeography

study of the geographic distribution of living things and the abiotic factors that affect their distribution

biomagnification

increasing concentrations of persistent, toxic substances in organisms at each trophic level, from the primary producers to the apex consumers

biomass

total weight, at the time of measurement, of living or previously living organisms in a unit area within a trophic level

biome

ecological community of organisms that is adapted to a characteristic set of environmental conditions

bleaching

when coral reefs expel their symbiotic, food-producing algae due to stressors, usually leading to the death of the reef

bog

wetlands that develop in depressions where water flow is low or nonexistent

boreal forest (taiga)

biome with cold, dry winters and short, cool, wet summers; dominated by coniferous trees

brackish

the dilute seawater associated with estuaries

canopy

branches and foliage of trees that form a layer of overhead coverage in a forest

carbon footprint

how much carbon dioxide is produced by an individual or per capita

channel

width of a river or stream from one bank to the other bank

chapparal

a warm-to-hot biome with a dry/wet cycle; dominated by shrubs well adapted to periodic fires and dormancy

chemoautotroph

organism capable of synthesizing its own food using energy from inorganic molecules

conceptual model

(also, compartment models) ecosystem model that consists of flow charts that show the interactions of different compartments of the living and non-living components of the ecosystem

coral reef

ocean ridges formed by marine invertebrates living in warm, shallow waters within the photic zone

cryptofauna

invertebrates found within the calcium carbonate substrate of coral reefs

dead zone

area within an ecosystem in lakes and near the mouths of rivers where large areas of ecosystems are depleted of their normal flora and fauna; these zones can be caused by eutrophication, oil spills, dumping of toxic chemicals, and other human activities

detrital food web

type of food web in which the primary consumers consist of decomposers; these are often associated with grazing food webs within the same ecosystem

ecological pyramid

(also, Eltonian pyramid) graphical representation of different trophic levels in an ecosystem based of organism numbers, biomass, or energy content

ecosystem

community of living organisms and their interactions with their abiotic environment

ecosystem dynamics

study of the changes in ecosystem structure caused by changes in the environment or internal forces

ectotherm

organisms whose internal temperature is externally regulated

emergent vegetation

wetland plants that are rooted in the soil but have portions of leaves, stems, and flowers extending above the water’s surface

endemic

species found only in a specific geographic area that is usually restricted in size

endotherm

organisms whose internal temperature is internally regulated

epiphyte

plants that grow commensally or mutualistically on other plants

equilibrium

the steady state of an ecosystem where all organisms are in balance with their environment and with each other

estuary

biomes where a source of fresh water, such as a river, meets the ocean

eutrophication

process whereby nutrient runoff causes the excess growth of microorganisms, depleting dissolved oxygen levels and killing ecosystem fauna

evaporation

transition from water to water vapor

fallout

direct deposit of solid minerals on land or in the ocean from the atmosphere

food chain

linear representation of a chain of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics; not as useful for ecologists

food web

graphic representation of a holistic, non-linear web of primary producers, primary consumers, and higher-level consumers used to describe ecosystem structure and dynamics

forbs

herbaceous flowering plants

gross primary productivity

rate at which photosynthetic primary producers incorporate energy from the sun

grazing food web

type of food web in which the primary producers are either plants on land or phytoplankton in the water; often associated with a detrital food web within the same ecosystem

halophyte

plants that tolerate salty conditions

holistic ecosystem model

study that attempts to quantify the composition, interactions, and dynamics of entire ecosystems; often limited by economic and logistical difficulties, depending on the ecosystem

humus

rich organic matter in soil

hydrologic cycle

cycle of water molecules through the geosphere, hydrosphere, and atmosphere

hydrosphere

area of the Earth where water movement and storage occurs

incomplete ingestion

some consumers eat only a part of their food, leaving some calories unused

infiltrates

precipitation that soaks into the ground

intertidal zone

part of the ocean that is closest to land; parts extend above the water at low tide

lakes and ponds

standing water that is stratified in the summer; spring and fall mixing bring oxygen and nutrients to the upper layers

leach

chemical removal of a particular element from the lithosphere

marshes and swamps

characterized by slow and steady water flow

mesocosm

portion of a natural ecosystem to be used for experiments

microcosm

re-creation of natural ecosystems entirely in a laboratory environment to be used for experiments

migration

the movement of an organism from one place to another

net consumer productivity

energy content available to the organisms of the next trophic level

neritic zone

part of the ocean that extends from low tide to the edge of the continental shelf

net primary productivity

energy that remains in the primary producers after accounting for the organisms’ respiration and heat loss

net production efficiency (NPE)

measure of the ability of a trophic level to convert the energy it receives from the previous trophic level into biomass

nocturnal

organisms that are active at night; common in arid ecosystems

non-renewable resource

resource, such as fossil fuel, that is either regenerated very slowly or not at all

ocean upwelling

rising of deep ocean waters that occurs when prevailing winds blow along surface waters near a coastline

oceanic zone

part of the ocean that begins offshore where the water measures 200 m deep or deeper

pelagic realm

(also, pelagic zone) open ocean waters that are not close to the bottom or near the shore

percolation

movement of water through the pores in the soil or rocks

permafrost

perennially frozen portion of the Arctic tundra soil

photic zone

portion of the ocean that light can penetrate

photoautotroph

photosynthetic autotrophs

planktivore

animal species that eats plankton

precipitation

rain or snow

productivity

the percentage of energy entering the ecosystem incorporated into biomass in a particular trophic level

primary producer

trophic level that obtains its energy from sunlight, inorganic chemicals, or dead and/or decaying organic material

pyramid of biomass

measures the amount of energy converted into living tissue at the different trophic levels

pyramid of energy

indicates energy flow through the trophic levels

pyramid of numbers

measures the relative amount of individuals across trophic levels

residence time

measure of the average time an individual water molecule stays in a particular reservoir

resilience (ecological)

speed at which an ecosystem recovers equilibrium after being disturbed

resistance (ecological)

ability of an ecosystem to remain at equilibrium in spite of disturbances

rivers and streams

continuously moving bodies of water that carry large amounts of water from the source, or headwater, to a lake or ocean

runoff

the flow of fresh water either from rain or melting ice

savanna

hot grassland with extensive dry season; dominated by grasses and forbs

second law of thermodynamics

states whenever energy is converted from one form to another, there is a tendency toward disorder (entropy) in the system

secondary consumer

usually a carnivore that eat primary consumers

simulation model

ecosystem model that is created with computer programs to holistically model ecosystems and to predict the effects of environmental disturbances on ecosystem structure and dynamics

source water

point of origin of a river or stream

stratification

the separation of water into layers, often by temperature or salt content

subduction

movement of one tectonic plate beneath another

sublimation

transition of ice to water vapor

subtropical desert

hot, very dry biome dominated by perennial vegetation well adapted to the biome

temperate forest

biome with warm summers, cold winters, and fairly constant precipitation year-round; dominated by deciduous trees

temperate grassland (prairie)

biome with hot summers and cold winters; summer rains allow plant growth but winter is a time of dormancy; dominated by dense grasses

tertiary consumer

carnivore that eat other carnivores

thermocline

layer of water with a temperature that is significantly different from that of the surrounding layers

trophic level

position of a species or group of species in a food chain or a food web

trophic level transfer efficiency (TLTE)

energy transfer efficiency between two successive trophic levels

tropical wet (rain) forest

terrestrial biome found in equatorial regions characterized by stable hot temperatures, high annual rainfall, and plants with broad evergreen leaves

turnover (fall and spring)

seasonal process that recycles nutrients and oxygen from the bottom of a freshwater ecosystem to the top

understory

short shrubby foliage under the canopy of a forest

wetland

environments in which the soil is either permanently or periodically saturated with water