Ecology test terms Flashcards
Ecology
the scientific study of the interactions between organisms and the environment
Microclimate
Climate patterns on a very fine scale
Macroclimate
Large-scale patterns in climate; climate of an entire region
Abiotic
Nonliving, referring to the physical and chemical properties of an environment
Biotic
Pertaining to the living factors (organisms) in an environment
Biome
Any of the world’s major ecosystem types, characterized by adaptations of organisms to that particular environment
Photic zone
The narrow top layer of an ocean or lake where light penetrates sufficiently for photosynthesis
Aphotic zone
The part of an ocean or lake beneath the photic zone where light does not penetrate sufficiently to permit photosynthesis
Detritus
Dead organic matter
Population
A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring
Density (of a population)
The number of individuals per unit area or volume
Dispersion (of a population)
The pattern of spacing among individuals within the boundaries of a population
Immigration
The influx of new individuals into a population from other areas
Emigration
The movement of individuals out of a population
Territoriality
A behavior in which an animal defends a nounded physical space against encroachment by other individuals usually of its own species
Demography
The study of changes over time in the vital statistics of populations, especially birth rates and death rates
Survivorship curves
A plot of the number of members of a cohort that are still alive at each age; one way to represent age-specific mortality
Zero population growth
A period of stability in population size, when additions to the population through births and immigration are balanced by subtractions through deaths and emigration
Exponential population growth
Growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time
Carrying capacity
The maximum population size that can be supported by the available resources, symbolized as K
K- selection
Selection for life history traits that are sensitive to population density; also called density-dependent selection
r-selection
Selection for life history traits that maximize reproductive success in uncrowded environments; also called density-independent selection.
density independent
Referring to any characteristic that is not affected by population density
density dependent
Referring to any characteristic that varies with population density
Population dynamics
The study of how complex interactions between biotic and abiotic factors influence variations in population size
Community
All the organisms that inhabit a particular area; an assemblage of populations of different species living close enough together for potential interaction
Interspecific interactions
A relationship between individuals of two or more species in a community
Interspecific competition
Competition for resources between individuals of two or more species when resources are in short supply
Competitive exclusion
The concept that when populations of two similar species compete for the same limited resources, one population will use the resources more efficiently and have a reproductive advantage that will eventually lead to the elimination of the other population
Ecological niche
the sum of a species’ use of the biotic and abiotic resources in its environment
Resource partitioning
The division of resources to avoid interspecific competition for limited resources in an ecosystem
Character displacement
The tendency for characteristics to be more divergent in sympatric populations of two species than in allopatric populations of the same two species
Predation
An interaction between species in which one species, the predator, eats the other, the prey
Mimicry (not specific batesian vs. mullerian)
When one or more species resemble each other to gain an advantage
Herbivory
An interaction in which an organism eats part of a plant or alga
Commensalism
A symbiotic relationship in which one organism benefits but the other is neither helped nor harmed
Parasite
An organism that feeds on the cell contents, tissues, or body fluids of another species (the host) while in or on the host organism. parasites harm but usually do not kill their host.
Mutualism
A symbiotic relationship in which both participants benefit
Symbiosis
An ecological relationship between organisms of two different species that live together in direct and intimate contact
Species richness
The number of species in a biological community
Species diversity
The number and relative abundance of species in a biological community
Relative abundance
The proportional abundance of different species in a community
Invasive species
A species, often introduced by humans, that takes hold outside its native range
Biomass
The total mass of organic matter comprising a group of organisms in a particular habitat
Food chain
The pathway along which food energy is transferred from trophic level to trophic level, beginning with producers
Trophic structure
The different feeding relationships in an ecosystem, which determine the route of energy flow and the pattern of chemical cycling
Keystone species
A species that is not necessarily abundant in a community yet exerts strong control on community structure by the nature of its ecological role or niche
Dominant species
A species with substantially higher abundance or biomass than other species in a community. DOminant species exert a powerful control over the occurrence and distribution of other species.
Food web
The interconnected feeding relationships in an ecosystem
Energetic hypothesis
The concept that the length of a food chain is limited by the inefficiency of energy transfer along the chain
Ecosystem engineers
An organism that influences community structure by causing physical changes in the environment
Biomanipulation
An approach that applies the top-down model of community organization to alter ecosystem characteristics. For example ecologists can prevent algal blooms and eutrophication by altering the density of higher-level consumers in lakes instead of by using chemical treatments
Disturbance
A natural or human-caused event that changes a biological community and usually removes organisms from it. Disturbances, such as fires and storms, play a pivotal role in structuring many communities.
Ecological succession
Transition in the species composition of a community following a disturbance; establishment of a community in an area virtually barren of life
Primary succession
A type of ecological succession that occurs in an area where there were originally no organisms present and where soil has not yet formed
Secondary succession
A type of succession that occurs where an existing community has been cleared by some disturbance that leaves soil or substrate intact
Law of conservation of mass
A physical law stating that matter can change form but cannot be created nor destroyed. In a closed system, the mass of the system is constant
Primary producers
An autotroph, usually a photosynthetic organism. Collectively, autotrophs make up the trophic level of an ecosystem that ultimately supports all other levels
Primary consumers
An herbivore; an organism that eats plants or other autotrophs
Secondary consumers
A carnivore that eats herbivores
Tertiary consumers
A carnivore that eats other carnivores
Detritivores
A consumer that derives its energy and nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms; a decomposer
Decomposers
An organism that absorbs nutrients from nonliving organic material such as corpses, fallen plant material, and the wastes of living organisms and converts them into inorganic forms; a detritivore
Primary production
The amount of light energy converted to chemical energy (organic compounds) by the autotrophs in an ecosystem during a given time period
Secondary production
The amount of chemical energy in consumers’ food that is converted to their own new biomass during a given time period
Production efficiency
The percentage of energy stored in assimilated food that is not used for respiration or eliminated as waste
Biogeochemical cycles
Any of the various chemical cycles, which involve both biotic and abiotic components of ecosystems
Trophic efficiency
The percentage of production transferred from one trophic level to the next higher trophic level
Bioremediation
The use of organisms to detoxify and restore polluted and degraded ecosystems
Conservation biology
The integrated study of ecology, evolutionary biology, physiology, molecular biology, and genetics to sustain biological diversity at all levels
Biological augmentation
The approach to restoration ecology that uses organisms to add essential materials to a degraded ecosystem
Endangered species
A species that is in danger of extinction throughout all or a significant portion of its range
Threatened species
A species that is considered likely to become endangered in the foreseeable future
Ecosystem services
A function performed by an ecosystem that directly or indirectly benefits humans
Introduced species
A species moved by humans, either intentionally or accidentally, from its natie location to a new geographic region, also called non-native or exotic species
Biodiversity hot spot
A relatively small area with numerous endemic species and a large number of endangered and threatened species
Urban ecology
The study of organisms and their environment in urban and suburban settings
Critical load
The amount of added nutrient, usually nitrogen or phosphorus, that can be absorbed by plants without damaging ecosystem integrity
Biological magnification
A process in which retained substances become more concentrated at each higher trophic level in a food chain
Greenhouse effect
The warming of Earth due to the atmospheric accumulation of carbon dioxide and certain other gases, which absorb reflected infrared radiation and reradiate some of it back toward Earth.
Assisted migration
The translocation of a species to a favorable habitat beyond its native range for the purpose of protecting the species from human caused threats
Sustainable development
Development that meets the needs of people today without limiting the ability of future generations to meet their needs
Ecosystem
All the organisms in a given area as well as the abiotic factors with which they interact; one or more communities and the physical environment around them
