Ecology Exam 2 - Vocab

Alfred Lotka

Mathematician who helped develop equations for predator-prey interactions and competition.

algae

Algae are eukaryotic organisms (they possess a true nucleus, cell organelles, and cell walls).

allelopathy

A type of interference competition between plants involving the production and release of secondary chemicals by one…

amino acid

Amino acids are organic molecules that function as the building blocks of proteins.

Arthur Tansley

Ecologist who defined an ecosystem as including both living and nonliving components.

birth rate

The birth rate is the rate at which females in a population give birth over some defined…

carrying capacity (K)

Largest population an environment can sustainably support.

character displacement

When two species compete, natural selection may reduce the strength of competition by changing some characteristic of…

Charles Elton

Ecologist who helped develop the concept of an organism's niche and food-chain relationships.

competition

Competition is the interaction between two organisms that use the same limited resource.

competition coefficient

Competition coefficients represent the per capita effect on the growth of one species (species 1) of another…

competitive exclusion principle

The competitive exclusion principle states that no two species can coexist in exactly the same ecological niche.

death rate

The death rate is the rate at which individuals in a population die over some defined time period.

desiccate

To dessicate means to lose water and dry out.

detritus

Detritus is simply particulate dead organic matter.

direct effect

Generally, a direct effect is produced when one individual or species directly impacts another without the interaction…

dispersal

Dispersal is an ecological process by which organisms move from one place of residence to another.

diurnal

Diurnal means daily or occurring in the daytime.

dN/dt

Instantaneous change in population size over time; the slope of the population-versus-time curve.

equation for a line

Formula y = mx + b, which describes a straight line.

equilibrium population size

A single species has reached its equilibrium population size when its population is no longer growing or contracting.

Exponential growth

Population growth that accelerates when resources are unlimited.

Exponential decay

A quantity decreases rapidly at first, then more slowly as less remains.

fecundity

Fecundity is the potential reproductive capacity of an individual organism or population.

fitness

Fitness refers to how evolutionarily successful an individual is within a certain environment, relative to other individuals.

fundamental niche

A species' fundamental niche is the complete set of environmental conditions in which the species can potentially…

Georgii Gause

Biologist known for experiments supporting the competitive exclusion principle.

globally stable system

A system is globally stable if there is one state the system will reach no matter where…

heath

Heath are low-lying evergreen shrubs in the genus Erica .

indirect effect

An indirect effect is produced when an interaction between two individuals or species is mediated by a…

insectivore

An insectivore is an organism that primarily eats insects.

interference competition

Interference competition occurs when competing individuals (usually of the same species) directly interact in an attempt to…

interspecific competition

Interspecific competition occurs when individuals of one species limit the resources available to another species.

intraspecific competition

Intraspecific competition is competition between individuals of the same species.

intrinsic growth rate (r)

Maximum per-individual population growth rate with unlimited resources.

isocline

The word isocline comes from Greek roots, as a comination of the words for same (isos) and…

Joseph Grinnell

Ecologist who introduced the niche concept as the ecological space a species occupies.

life history trade-off

Due to physical constraints, maximizing one life history trait (e.g., fecundity) often comes at the expense of…

limiting resource

A limiting resource is a factor (e.g., a nutrient or space) that restricts the growth of an…

live yogurt

Yogurt is produced by the fermentation of milk with cultures of Streptococcus thermophilus and Lactobacillus delbrueckii sp.

mesquite

Mesquite is a group of over 40 species of trees and shrubs in the genus Prosopis .

meta-analysis

A meta-analysis is simply the analysis of analysis.

niche

A niche is the constellation of environmental conditions under which a species can survive.

noise

Static from a radio speaker or on a television screen is an example of noise.

null hypothesis

Statistics are often used to help us evaluate hypotheses or expectations using data from experiments or comparative studies.

nutrient

A nutrient is an element or molecule that is needed for life but which an organism cannot…

Paramecium

Paramecium is the genus name for a group of common, single-celled protozoa that are found in many…

parasitism

Parasitism is a form of symbiosis where one organism lives in close association with another and gains…

pathogen

A pathogen is a biological agent that produces a disease in its host.

phase plane

A phase plane is a plot of two system variables against each other (one on the x-axis…

phase portrait

A phase portrait, plotted on a phase plane, is a type of two-dimensional graph that describes how…

photosynthesis

Photosynthesis is the process by which autotrophic organisms use solar energy to convert water and carbon dioxide…

phytoplankton

Phytoplankton are small plants and photosynthetic bacteria that live and drift in the water of oceans and lakes.

predators

Strictly speaking, a predator is any species that eats another species.

preemption

Preemption is interference competition that occurs when an individual prevents other individuals from occupying a location by…

probiotic

A probiotic substance is one that stimulates the growth of microorganisms with beneficial properties.

proboscis

In insects, the proboscis is a sucking mouthpart that is long and generally tubular.

realized niche

A species' realized niche is the set of environmental conditions in which the species is actually found…

relative humidity

Relative humidity is the ratio of the amount of water vapor actually present in the air to…

resource competition

Resource competition occurs when individuals compete indirectly by consuming a shared resource.

self-thinning

Self-thinning is a decline in population density resulting from intraspecific competition (i.e., competition between individuals of the…

spatial and temporal variation

Observations made at different locations or different points in time typically take on different values.

steady state

When a system is in a steady state, its overall behavior is not changing over time.

strains

Bacteriologists often develop pure cultures of bacteria that arise from a single individual.

territoriality

The establishment of an area by one or more organisms from which others are at least partly excluded.

unstable equilibrium

If a process or system is at an equilibrium, its overall behavior is not changing over time.

urban heat island

Urban heat island refers to the observation that cities tend to be warmer than surrounding rural areas…

Vito Volterra

Mathematician who helped develop equations describing predator-prey dynamics and competition.

Alice and the Red Queen

Idea that species must continually adapt to keep up with evolving predators, parasites, or hosts.

alleles

Alleles are different versions of a gene.

biocontrol

In biocontrol (short for biological control), people manage a pest or weed using its natural enemies.

coevolution

Coevolution occurs when two species that live in close association both adapt in response to selective pressure…

cyst

Many parasites spend part of their life cycle as cysts, protected by a tough outer wall.

density dependence

The influence of density-dependent factors on the dynamics of a population changes with the size of that population.

ecology of fear

Predators can reduce the number of prey directly by killing individuals.

emigration

Emigration is the movement of living individuals out of a population.

functional response

Functional response describes how a predator's feeding rate changes with prey density.

generalist

A generalist is an organism that can exploit several (often numerous) different species or take advantage of…

handling time

Handling time is the amount of time that it takes a predator to kill and consume one…

herbivore

Herbivores are organisms that eat living plants, algae, or parts thereof.

host

The organism that a pathogen or parasite lives in or feeds on is its host.

immigration

Immigration is the movement of individuals into a population or area.

linear relationship

A linear relationship between two variables appears as a straight line on a graph because the rate…

metapopulation

A metapopulation is a collection of spatially distinct subpopulations of the same species that are connected via dispersal.

natural selection

Natural selection is a systematic difference in the survival and reproductive success of individuals with different genotypes…

parasite load

Parasite load is a measure of the severity of infection in a host organism.

prey switching

Prey-switching, or frequency-dependent predation, occurs when predators show a preference for the most- abundant type of prey.

protists

Protists are microscopic eukaryotic organisms (they possess a true nucleus, organelles, and cell walls).

reciprocal selection

Reciprocal selection occurs when two species both exert pressure on the other through natural selection.

recombination

Genetic recombination occurs through sexual reproduction and the process of crossing over during meiosis.

search image

Predators benefit from being able to efficiently recognize and find their prey.

specialist

A specialist is an organism that exploits only one (or very few) species or can only take…

trade-offs

Many traits under selection have multiple effects on organisms, leading with both benefits and costs.

trophic level

An organism's trophic level describes its position in the food chain.

type I functional response

In a type I functional response, the predator's rate of prey consumption shows a linear increase with…

type II functional response

A type II functional response is the one most commonly seen in nature.

type III functional response

The type III functional response is similar to the type II response at high prey densities, when…

well-mixed population

A well-mixed population is one where each individual has an equal probability of interacting with all other…

acclimation

Acclimation describes change in the morphology, physiology or behavior of an organism that occurs in response to…

adaptation

An adaptation is a genetically-determined trait that increases an individual's fitness—that is, its genetic contribution to future generations.