a13 populations (1.1/2/3)
- Created by: phebez
- Created on: 06-10-15 18:52
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- A population is all the organisms of 1 species in a habitat.
- within a habitat a species occupies a niche governed by adaptation to both biotic and abiotic conditions
- A13 POPULATIONS
- INVESTIGATI-NG POPULATIONS
- VARIATION IN POPULATION SIZE
- BIOTIC
- concerned with the activities of living organisms and include competition and predation
- BIOTIC
- QUADRATS/ TRANSECTS
- FACTORS: size ; number of sample quadrats (larger number of quadrats =more reliable) ; position of each quadrat
- transects : line or a belt
- abundance is measured by either frequency or % cover.
- frequency is the likelihood of a particular species occurring in a quadrat
- % cover is an estimate of the area within a quadrat that a particular plant species cover
- INVESTIGATI-NG POPULATIONS
- some time later, a given number of individuals is collected randomly
- number of marked individuals recorded
- they are released back into the community
- A known number of animals are caught and marked
- MARK RELEASE RECAPTURE
- MARK RELEASE RECAPTURE
- A known number of animals are caught and marked
- 1)slow growth- initially small # of individuals reproduce to slowly build up their number
- 2)rapid growth- ever-increasing # of individuals continue to reproduce
- 3)stable- declines due to food supply or to increased predation until more or less stable
- population growth curves
- VARIATION IN POPULATION SIZE
- BIOTIC
- concerned with the activities of living organisms and include competition and predation
- BIOTIC
- VARIATION IN POPULATION SIZE
- 2)rapid growth- ever-increasing # of individuals continue to reproduce
- TEMPERATURE
- the more energy the organisims expend in trying to maintain their normal body temp.
- this leaves less energy for individual growth-mature more slowly-reproductive rate slows- population gets smaller
- ABIOTIC
- the more energy the organisims expend in trying to maintain their normal body temp.
- WATER/ HUMIDITY
- affects transpiration rates in plants and the evaporation of water from animals
- ABIOTIC
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