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Population Histograms
Study populations in terms of structure and age
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Climax Species
(Hard Wood Trees) can tolerate shade, longest life cycles. Stabilizes environment.
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Seral/Intermediate Species
(Shrubs, Soft Trees) can tolerate fluctuations, longer life cycles. Requires more nutirents.
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Pioneer Species
the first to arrive (lichen, weeds) resists direct sun and temperatures
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Secondary Succession
following a destructive event
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Primary Succession
no community existed before, an ecological disturbance
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Predator/Prey
control each others numbers
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Mutualism
both species benefit
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Commensalism
one species benefits with no effect on the other
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Parasitism
one species benefits while harming another
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Coevolution
species adapting due to pressure
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Gause's Principle
If 2 populations have the same niche one will be eliminated
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intraspecific competition
competition within a species
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interspecific competition
competition involving different species
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5 factors of k vs r species
- -Life Span
- -Maturation rate
- -Number of off spring
- -Organism body size
- -Amount of parental involvement
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k-species
large slowly reproducing species
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r-species
small highly reproductive species with a short life span
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Density dependent factors
increase population size results in increased results
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Density independent factors
Will affect a population regardless of size
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Growth Phases
- 1.Lag: Natality and immigration are greater than or equal to mortality and emigration
- 2.Growth: Natality and immigration are greater than Mortality and Emigration
- 3.Stationary: Natality and Immigration are equal to Mortality and Emigration
- 4.Decline: Natality and Immigration are less than Mortality and Emigration
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Distribution of Populations
- -Random: no order; no attraction or repulsion, spaced out randomly
- -Uniform: order; competition for space or food. Spread out evenly
- -Clumped: order, individuals are grouped in patches.
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Bottleneck Effect
Quick reduction of a population (starvation, disease, natural disasters) causes a surviving pop to produce less offspring
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Founder Effect
A population formed from a small group holds limited representation of the original population
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Evolutionary Change happens due to
- 1.Mutation:DNA change during meiosis
- 2.Gene Flow: net movement of alleles from one pop to another (due to migration)
- 3.Non-random mating: selective breeding
- 4.Genetic Drift: Change in frequency in breeding due to random events
- 5.Natural Selection: Some survive better than others.
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Hardy-Weinberg conditions
- -Large Population
- -Random Mating
- -No Mutation
- -No Migration
- -No Natural Selection
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Hardy-Weinberg Principle
if all other factors remain constant the gene pool will remain constant, generation after generation
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Gene Pool
all the alleles in a population
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Population
The same species, in the same place at the same time
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