Population A2
- Created by: rebekah
- Created on: 08-01-14 11:03
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- Population
- Variation in population
- Population growth curves
- 1) A period of slow growth as the pop is small so reproduction takes time to increase population
- 2) A period of rapid growth-population size doubles
- 3) Stables state- no growth-fluctuations due to changes in factors e.g. food supply
- Factors
- Abiotic-Those concerned with non living parts of the environment.
- pH
- Light intensity
- Temperature
- Water and humidity
- Biotic-Those concerned with the activities of living organisms and include competition, predation.
- Abiotic-Those concerned with non living parts of the environment.
- Population growth curves
- Competition
- Two types:
- Intraspecific competition-within species
- Limpets/oak tree
- Interspecfic competition-between species
- When two species initially occupy the same niche-one has a competitive edge
- Intraspecific competition-within species
- Two types:
- Predation
- Occurs when one organism is consumed by another.
- Effects on predator-prey relationship
- 1) Predators eat prey-thus reducing population
- 2) Fewer prey mean predators have to compete so predators die
- 3) Less predators mean more prey survive-population increases
- 4) Predators now have ample food so population increases
- Human population
- Reasons for population explotions
- Development of agriculture
- Industrial revolution
- Temporary reversals in upward trend
- War
- Disease
- Famine
- Factors effecting population rise
- Birth/death rates
- Immigration/ Emmigration
- % pop growth rate in a given time
- =
- Pop change per year / pop at the beginning at time period
- X 100
- Pop change per year / pop at the beginning at time period
- =
- Factors effecting birth rate
- Economic conditions
- Culture/religious beliefs
- Social pressures
- Birth conrtol
- Political factors
- DTM
- 1) small and stale-High birth and death rates 2)early expansion-high birth rates, decreasing death rates 3) Late expansion-decreasing birth rates, low death rates 4) Large and stable-Low birth and death rates
- Reasons for population explotions
- Variation in population
- DTM
- 1) small and stale-High birth and death rates 2)early expansion-high birth rates, decreasing death rates 3) Late expansion-decreasing birth rates, low death rates 4) Large and stable-Low birth and death rates
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