Populations Flashcards
Define succession
The change in structure and species composition of a community over time with progression to a climax community
Sere/serial stage
The different stages in succession when a particular species dominates. The community changes with each serial stage
Define pioneer species
The first species to colonise and uninhabited area in ecological succession
Define climax community
A stable community that has reached equilibrium with its environment, and no further changes occur
Explain ammonification
Saprotrophs convert:
Urea —> NH3 —> NH4+
Or
proteins –(protease)–> a.a. –(deaminase)–> NH2 —> NH3 —> NH4+
Explain nitrification
Free living, aerobic nitrifying bacteria
NH4+ –(nitrosomonas)–> NO2- –(nitrobacter)–> NO3-
Define ecosystem
A community of organisms that interact with each other and with their physical environment. They are made up of biotic and abiotic components.
Define a fugitive species
A species that cannot tolerate competition. To increase their numbers they reproduce rapidly and have effective dispersal mechanisms. They invade new environments rapidly (e.g. algae and weeds)
Define an equilibrium species
A species that control their population by competition within a stable habitat. Sigmoid shape curve pattern of growth called one step growth curve
Define environmental resistance
Environmental factors that slow down population growth. Also called limiting factors
Define ecology
The study of the relationship between living organisms and their non-living or physical environment
Define ecosystem
A community of organisms that interact with each other and with their physical environment. They are made up of biotic and abiotic components
Define community
All the populations of different species that coexist and interact in the same habitat at the same time
Define population
A group of organisms of on species occupying one habitat at the same time that are able to breed with each other
Define Gross Primary Productivity
The rate of production of chemical energy in organic chemicals by photosynthesis per unit area and time
Define net primary productivity
GPP - respiratory losses
