7.4 - Populations in ecosystems Flashcards
What is a population?
Number of organisms of the same species
What is a community?
Number of populations in an area
What is an ecosystem made up of?
A community and the non-living components of its environment
Size of ecosystems
Varies from very small to very large
What is a niche?
The role a species plays in a habitat
What is a habitat?
An area where one or more organisms live
Define biotic factor
Living factors
E.g predation
Define abiotic factor
Non-living factor
E.g pH, moisture, light intensity, temperature
Define carrying capacity
The certain size of population of a species which an ecosystem can support
Why do population sizes of species vary?
The effect of abiotic factors
Interactions between organisms: inter specific and intraspecific competition and predation
Define interspecific competition
Competition between organisms of different species
Define intraspecific competition
Competition between organisms of the same species
Name two ways the size of a population can be estimated
Randomly placed quadrants or quadrants along a belt transect for slow-moving or non-motile organisms
Mark-release-recapture for motile organisms
What are some assumptions made when using the mark-release-recapture method?
Species distribute randomly
No marks rub off
Few births or deaths in population
Describe the procedure of the mark-release-recapture method
Collect sample, mark and release
Ensure marking is not harmful
Allow species to randomly distribute before collecting second sample
Population = number in first sample x number in second sample / number recaptured
