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22 Cards in this Set
- Front
- Back
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1. Population
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all the individuals of a species that live in one place at one time
A. People in Omaha B. People in world C. Ducks in eastern NE D. Deer in forest |
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2. Devil’s Hole Pupfish
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A. Death Valley
B. Isolated Area C. Only population of this fish in the entire world |
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3. Demography
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A. Involves a statistical study of population
B. The environment’s capacity to support the population limits its size |
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4. 3 Key features of populations
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A. Population size- size of population more in danger
B. Population density- number of individuals in a certain area, 1 individual/ Every 10 square miles C. Dispersion- the way the individuals are arranged |
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5. Population Model
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A. A hypothetical population that has the key characteristics of a real population
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. Caring Capacity
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the maximum population size that an environment can support
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. r- strategists
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A. Population that grows very fast (population explosions) and they die quickly
B. Some insects, annual plants, bacteria C. Young get little or NO care from parents D. Young mature and grow quickly |
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. k- strategists
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A. Whales, rhinos, redwood trees
B. Slow population growth live in environments that are stable and predictable |
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. Humans
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A. Many traits of k- strategists
B. But we have changed the environment to grow and increase caring capacity |
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Hardy- Weinberg Principle
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A. 1908
B. Populations don’t change unless evolutionary forces act upon them C. True only for large populations in which individuals mate randomly and that forces that change the proportions of alleles are not acting D. It was MATH to predict the frequency of each genotype in a population if you know the alleles frequency |
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5 forces causing evolution or changes in a population
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A. Mutation- changes pf alleles does not happen often
B. Migration a. Movement of individuals from one population to another b. Creates a gene flow (mixing of new genes and alleles) |
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Nonrandom mating
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when individuals mate with those of their own genotype, Inbreeding- mating with relatives
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Genetic Drift
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1. In small populations
2. Chance event (fire) hare caused frequency of alleles to change 3. This (in the past) has affected humans- we used to live in small, isolated groups or tribes |
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. Natural Selection
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1. Causes deviations from the Hardy- Weinberg Prin. By directly changing the frequency of alleles
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How Natural Selection Shapes Populations
12. Natural Selection |
- reduces the frequency of a harmful recessive alleles slowly because very few individuals are homozygous recessive and express the trait
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Genetic Polymorphism
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when a gene in a population has more then one allele appear at a significant frequency
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Polygenic Trait
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in- a characteristic influenced by several genes, human height, often results in a normal distribution/ curve or bell curve
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. Directional selection
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A. When selection acts to eliminate one of those 2 extremes from the range of phenotypes- then the genes promoting this extreme become less common
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16. Stabilizing Selection
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A. When selection acts to eliminate extremes at both ends of a range of phenotypes
B. It increases the number of individuals that are similar |
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17. Distributing Selection
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A. When selection acts to eliminate rather then favor the average
B. The population will have larger numbers of individuals at the 2 extremes |
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expontial growth
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curves up
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Liqistic growth
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curve like plateu
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