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Grade 12 IEB Population Ecology study guide test
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Grade 12 IEB Population Ecology study guide test
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Grade 12 IEB Population Ecology studyguide test
Ecology - ANS The study of the interactions of organisms with their physical and
biological environments.
Population ecology - ANS The fluctuations in the size of a population and the
factors (physical and social) that regulates these fluctuations.
Population size - ANS The total number of individuals
Natality - ANS birth rate
Mortality - ANS death rate
Immigration - ANS Individuals moving into a population and staying
Emigration - ANS Individuals leaving a population and not returning
Closed population - ANS a population that has no immigration and emigration with
other populations
Environmental resistance - ANS The total number of factors that stop a population
from reproducing at its maximum rate. Limiting factors build up this.
carrying capacity - ANS The population density that the environment can support.
The pop fluctuates around the carrying capacity.
Limiting factors - ANS Help to regulate the growth of a population.
Density independent factors - ANS Limit growth pop. Results natural factors, not
bcuz of no. of organisms. PHYSICAL FACTORS (temp, humidity, rainfall)
CATASTROPHIC EVENTS (flood, fire, earthquake)
, Density dependent factors - ANS Greater effect pop density is high. More crowded:
COMPETE (resources-food,water,light,oxygen,space,shelter) PREDATORS (more
easily found) DISEASE (spread easily)
stable population - ANS Numbers decrease-size exceeds cc
Increase-fall below cc
FLUCTUATES
Unstable population - ANS Pop far exceeds cc
Habitat: deteriorating rapidly, low cc, not being able to support pop, decrease, extinct
Direct method - ANS Counting every single individual in pop. CENSUS.
Organisms=large. Area=not too large. Individuals=slow, stationary, stay in fixed position.
Area too large=aerial pics, helicopters.
Quadrat Method of Estimating Populations - ANS Counting no. individuals in
quadrats, using no. calculate pop size of total are.
N=average number in sample x size of whole habitat/size of quadrat
Mark-recapture method - ANS Individuals caught and marked, released. Another
sample captured, number of marked individuals counted. Animals: mobile, not easily
visible.
P=M x C/R
M=total number marked animals initially
C=total number of animals caught in 2nd sample
R=total number of marked animals in 2nd sample
Predation - ANS Biological interaction, predator kills and eats the prey.
Role of predators - ANS 1) regulating prey species.
2) increasing biodiversity
3) prey pop genetically fit
4) food for scavengers
PPR Aphid-ladybug - ANS Aphid - prey
Ladybug - predator
PPR lion-zebra - ANS Evolve adaptations-speed of movement, co-evolution.
Advantageous.
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