Chapter 1- Populations Flashcards
What is meant by biotic?
The living components that make up an environment eg competition and predation
What is meant by the term environment?
Both living and non-living factors of an area
What is meant by abiotic
The non-living components of an environment, eg temperature and rainfall
What is an ecosystem?
More or less self-contained functional unit in ecology made up of all the interacting biotic and abiotic factors in a specific area
What is meant by the term population?
A group of interbreeding organisms of one species in a habitat
What is a community?
All populations of different organisms living and interacting in a particular place at the same time
What is a habitat?
The place where a community of organisms lives
What is an ecological niche?
All biotic and abiotic conditions required for an organism to survive, reproduce and maintain a viable population
What 3 factors should be considered when using a Qaudrat?
The size of the Quadrat.
The number of sample Quadrats.
The position of each Qaudrat.
Why is random sampling important?
To avoid any bias. This makes the data obtained more valid
What is a good method of random sampling?
Generate a series of random coordinates
Lay out tape measure at right angles along sides of area being studied
Place Quadrats at each coordinated along tape
How do we measure species abundance systematically?
Using a transect. Can either be a line or a belt transect
How do we measure abundance from a random or systematic sample?
Either by frequency or percentage cover. Frequency can be used for large individual organisms. Percentage cover can be used for plants
How is a population size calculated using the mark-release-recapture technique?
Estimated population size=
Total no. Of individuals in 1st sample x
Total no. Of individuals in 2nd sample
(Divided by)
No. Of marked individuals recapturedWhat are some of the assumptions of the mark-release-recapture technique?
Anything from:
- the marked individuals distribute themselves equally and have sufficient time to do so
- there is no immigration into or emigration our of the population
- there are few deaths and births within the population
- the method of marking is non- toxic and doesn’t make the individual more obvious to predators
- the mark is not lost during the investigation
- the proportion of marked:unmarked individuals in the 2nd sample is the same as the proportion in the population as a whole
