Populations Flashcards
Define:
Population
All the organisms of one species in a particular habitat.
Define:
Habitat
The place where the organism lives.
Define:
Community
Populations of different species in a habitat make up a community .
Define:
Ecosystem
All the organisms living in a particular area and all the non-living (abiotic) conditions.
Define:
Abiotic
The non-living factors of an ecosystem.
Define:
Biotic
The living factors in an ecosystem.
Define:
Niche
The role that a species plays within it’s habitat.
Define:
Adaptation
A characteristic that a species has which increases chance of survival and reproduction.
What interactions does a niche include?
Biotic and abiotic interactions.
How many species can occupy a niche?
One.
A niche is unique.
Investigating populations…
What type of sample is best to use?
Random
Investigating populations…
Describe how to take a random sample.
1) Select an area to take the sample from
2) Divide the area up into a grid and number the sections.
3) Use a random number generator to select a site.
4) Use an appropriate technique e.g. Mark-release-recapture for animals, or a quadrat for plants.
5) Return habitat to natural state.
Investigating populations…
Describe the mark-release-recapture method
Firstly, capture a certain number of the species.
Mark them in a way that is not harmful to them, e.g. a small paint mark.
Release the sample back into site.
After leaving a suitable amount of time, return to the site and recapture the same size sample.
Count the number of marked species.
Investigating populations…
How can you calculate a total population estimation?
MULTIPLY the number of organisms CAUGHT in the first sample and the number CAUGHT in the second sample.
DIVIDE this figure by the number of MARKED organisms in the SECOND sample.
Investigating populations…
How can percentage cover be calculated?
By taking the average of all samples collected.