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36 Cards in this Set
- Front
- Back
Define gene pool. |
the various alleles of all the genes in all the members of a population |
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Define genetic equilibrium. |
allele frequency remains stable which results in no evolution occurring |
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Name the five conditions that must be met to maintain genetic equilibrium. |
1. Large population - no genetic drift 2. No mutations 3. No migration 4. No natural selection 5. Random mating |
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Define natural selection. |
organisms that are better adapted to their environment tend to survive and produce more offspring |
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Define genetic drift |
changes to the allele frequency as a result of chance |
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Define gene flow |
the movement of alleles from one population to another |
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Define the bottleneck effect |
big to small population = not very much variability in alleles and a change in the frequency |
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Define the founder effect |
when individuals find a new colony, only a fraction of the original gene pool is represented |
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Define non random mating. |
pairing up not by chance but according to genotype and phenotype |
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What do mutations do to the gene pool? |
changes the allele frequency with new alleles |
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Define carrying capacity |
the maximum population that can be maintained by a given supply of resources |
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Define biotic potential |
the ability of a population to increase under ideal environmental conditons |
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Define environmental resistance |
resources that LIMIT a population from reaching biotic potential |
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As the number of individuals increase, what happens to the environmental resistance? |
it increases |
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What is the formula for calculating the growth rate? |
change in individuals / change in time |
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What is the formula for calculating the per capita growth rate? |
change in population size / initial population size |
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What is the formula to calulate population density? |
Total number of individuals / area or volume |
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Explain exponential growth. (6) |
1. J-shaped curve. 2. The population size increases by a fixed rate per a fixed unit of time 3. unlimited resources 4. only limit on growth is biotic potential 5 natality is always higher than morality 6. 4 phases (log, growth, stationary, death) |
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Explain Logistic growth. (2) |
1. S - shaped curve 2. 3 phases (log, growth & stationary) |
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Define open population. |
a population in which change in number and density is determined by natality, mortality, emmigration and immigration |
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Define closed population. |
a population in which change in number and density is determined only by natality and mortality |
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Draw a chart concerning the difference between K selected and R selected species. |
sheet is on google docs. |
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Define density-dependant factors |
Factors that limit population growth only at a specific density (number) |
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Define density independant factors |
facors that has the smae influence on a population at any population density |
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Name 3 Density dependant factors |
food, space, competition, predation, DISEASE, resources |
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Name 3 Density independant factors |
pesticide use, weather, chemicals, floods, fires, herbicides |
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Define intraspecific competition |
competition between the same species |
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Define interspecific competition |
competition between different species |
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Define commensalism (who benefits or doesn't and give an example) |
one organism benefits while the other is neutral. ex. barnacles on a whale |
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Define mutualism (who benefits or doesn't and give an example) |
Both organisms benefit from the relationship. ex. bees and flowers D |
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Define parasitism (who benefits or doesn't and give an example) |
the parasite benefits while the host is ususually harmed or even killed. ex. tape worms |
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Define succesion |
the slow, progessive replacement of one community by another |
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Define climax community. |
the final, relatively stable community reached dring successional stages |
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Define primary succesion and give its key event |
occupaton by plant life of an area not previously covered by vegetation. key event = soil production |
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Define pioneer species. give an example |
first species to appear during succesion. ex. moss |
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What is secondary sucession caused by? give an example |
a disturbance to habitat. ex fire |