Chapter 5- Population Size And Ecosystems Flashcards
Population
An interbreeding group of organisms of the same species occupying the same habitat
Birth Rate
The reproductive capacity of a population; the number of new individuals derived from reproduction per unit time
Immigration
The movement of individuals into a population of the same species
Equilibrium species
Species that control their population by competition rather than by reproduction and dispersal
Environmental resistance
Refers to environmental factors that slow down population growth
Biotic
A part of the environment of an organism that is living, e.g. Pathogens, predators
Abiotic
A part of the environment of an organism that is non-living, e.g. Air temperature, oxygen availability
Carrying capacity
The maximum number around which a population fluctuates in a given environment
Abundance
The number of individuals in a species in a given area or volume
Distribution
The area or volume in which the organisms of a species are found
Ecosystem
A characteristic community of interdependent species interacting with the abiotic components of their habitats
Habitat
The place in which an organism lives
Community
Interacting populations of two or more species in the same habitat at the time
Tropic level
Feeding level; the number of times that energy has been transferred between the sun and successive organisms along a food chain
Biomass
The mass of biological material in living, or recently living organisms
Saprobiont
A microorganism that obtains its food from the dead or decaying remains of other organisms
Gross primary productivity
The rate of reproduction of chemical energy in organic molecules by photosynthesis in a given area, in a given time, measured in kJ m-2 y-1
Net primary productivity
Energy in the plant’s biomass which is available to primary consumers, measured in kJ m-2 y-1
Primary productivity
The rate at which energy is converted by producers into biomass
Secondary productivity
The rate at which consumers convert the chemical energy of their food into biomass
Succession
The change in structure and species composition of a community over time
Climax community
A stable, self perpetuating community that has reached equilibrium with its environment, and no further change occurs.
Primary succession
The change in structure and species composition of a community over time in an area that has not previously been colonised
Pioneer species
The first species to colonise a new area is an ecological succession e.g. Algae, lichens and misses in a xerosere
Secondary succession
The changes in a community following the disturbance or damage to a colonised habitat
Niche
The role and position a species has in its environment, including all interactions with the biotic and abiotic factors of its environment
Mutualism
An interaction between organisms of two species from which both derive benefit
Commensalism
An interaction of two species from which one benefits but the other is not affected
Global warming
The increase of average global temperature, in excess of the greenhouse effect caused by the atmosphere’s historical concentration of carbon dioxide
Carbon footprint
The equivalent amount of carbon dioxide generated by an individual, a product or a service in a year
Nitrification
The addition of nitrogen to the soil, most commonly as nitrate NO2- and nitrate NO3- ions.
Nitrogen fixation
The reduction of nitrogen atoms in nitrogen molecules to ammonium ions by prokaryotic organisms
Eutrophication
The artificial enrichment of aquatic habitats by excess nutrients, often caused by run-off of fertilisers
