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EXAM 4, Nonrandom mating, Genetic drift, HEREDITY, Natural selection,…

- - - - All of the alleles of every gene in a population make up the gene pool
      - A population is a group of individuals of the same species that occupy the same region and can interbreed with each other
      - Allele frequency
        
        Number of copies of an allele in a population divided by the total number of alleles for that gene in a population
        
        Allele Relative Frequency
        
        Number of copies of an allele in a population
        
        Divided by
        
        The total number of all alleles for that gene in a population
      - Genotype frequency
        
        Number of individuals with a particular genotype in a population divided by the total number of individuals in a population
        
        Genotype Relative Frequency
        
        Number of individuals with a particular genotype in a population
        
        Divided by
        
        The total number of all individuals in a population
    - - No new mutations
      - No genetic drift. The population is so large allele frequencies do not change due to random sampling effects
      - No migration
      - No natural selection
      - Random mating
    - - The frequency of gametes carrying a particular allele is equal to the allele frequency for a population in Hardy-Weinberg equilibrium.
        Multiplying the allele frequencies gives the proportion of each allele combination in the population.
  - - - Changes in a population’s gene pool from generation to generation
      - Factors
    - - Dimorphic
        
        2 phenotypes
        Dominant-recessive systems
      - Polymorph = many phenotypes in a population
      - Example: Aquilegia
      - Color variation
      - Spur-length variation
      - Can be due to a single nucleotide polymorphism
    - - Bottleneck from long distance dispersal
      - Followed by adaptive radiation
      - Example: Hawaiian lobeliads
    - - Selection by humans
      - Crop breeders for thousands of years
      - Example Brassica
  - - - Steps summarized
      - Find your Min & Max values
      - Determine the number of bins
      - Count the number of observations for each bin
      - Draw bars for each bin with the frequency
- - - - Population size (N)
      - Exponential growth
      - Logistic growth
    - - Overshoot K
      - Result in die off
        Limited resources
    - - r = intrinsic growth rate
      - N = population size
      - K = carrying capacity
      - dN/dt = population change over time
      - Exponential growth
      - dN over dt equals r times N
      - Logistic growth
      - dN over dt equals r times N times the quantity one minus N divided by K
      - Model details for population growth
        
        Exponential growth
        
        dN/dt = rN
        
        Logistic growth
        
        dN/dt = rN[(K-N)/K] =
        rN(1-N/K)
    - - r-selected
        
        Grow exponentially
        
        Disturbed areas
        
        Weedy
        
        Annuals
        
        Little investment in defense
        
        Many, small fruits
      - K-selected
        
        Fluctuate around carrying capacity
        
        Fairly stable habitats
        
        Perennials
        
        Invest in defenses
        
        Resource-intensive fruits
    - - Plants must make trade-offs due to environmental necessities
        Many strategies exist
        
        Grime’s model
        
        Biotic
        
        Abiotic
        
        3 life stages
        
        C- Competitors
        
        S-Stress tolerators
        
        R-Ruderals
        
        Disturbance
        
        Resource availability
        
        Growth inhibitors
  - - - x = age
      - Nx= number of individuals alive at age x
      - Sx= proportion of individuals of age x that survive to age x+1;
      - Nx+1/Nx
      - lx= proportion of individuals that survive from birth (age 0) to age x;
        
        Nx/N0
      - Fx= average number of offspring born to a female while she is age x
      - lx(Fx) = average number of offspring per capita at age x
      - lx(Fx)x = average number of offspring per capita at time x, weighted by age x
      - Life table practice, R0
        
        Calculate the net reproductive rate (R0)
        
        Calculated by taking the sum of the offspring/individual column.
        
        Represents the expected number of offspring an individual will produce over its lifetime in the population.
        
        If R0>1, the population size increases.
        
        If R0<1, the population size decreases, and
        
        if R0=1, then population size does not change.
      - Life table practice, G
        
        Calculate the mean generation time (G)
        
        Calculated by taking the sum of the Age-weighted fecundity column and then dividing by the net reproductive rate
        
        Represents average time between two consecutive generations in the lineage of a cohort
        
        The average age between parent and offspring
      - Life table practice, r
        
        Calculate the intrinsic growth rate (r)
        Calculated by taking the natural log of the net reproductive rate divided by the mean generation time.
        
        If r>0, the population size increases.
        
        If r<0, the population size decreases, and
        
        if r=1, then population size does not change.
      - Survivorship curves and age structure
        
        How long did individuals survive
        
        Visual representation of survivorship
        
        Type I, typical of K-selected species
        
        Type III, typical of r-selected species
        
        Dependent on environment
        
        Same species can display all 3
        
        Poa annua survivorship curve
        
        Survivorship curves are plotted logarithmically
        
        Take survivorship (lx) and multiply by 1000
        
        Take the log10 of this value
        
        Plot against age to produce a figure
        
        Example: Type I curve
  - - - a group of actually or potentially interacting species living in the same location.
      - bound together by a shared environment and a network of influence each species has on the other.
      - factors affecting interactions include
        
        abiotic environment
        biotic interactions that occur between species
        
        Biotic interactions between species
        
        Range of interactions
        
        Beneficial interactions +
        
        Negative interaction -
        
        Facilitation (+/+)
        
        Benefits both
        
        Mutualism
        
        Pollination
        
        Commensalism (0/+)
        
        Benefits one, neutral to the other
        
        Amensalism (0/-)
        
        Negative to one & neutral to other
        
        Competition (-/-)
        
        Both are negatively impacted
        Competition for resources
        
        Predation (+/-)
        
        Herbivory
        Parasitism
    - - Predator
        
        P
        
        Negative impact on prey
        
        Positively impacted by prey
      - Prey
        
        N
        
        Positive impact on predator
        
        Negatively impacted by predator
    - - At low prey and predator population sizes, prey increase exponentially
      - As more food for predators is available, predator survival and reproductive success increases, resulting in predator population growth following that of their prey
      - As predator populations increase, prey death rate exceeds birth rate, resulting in prey decline
      - As prey number declines, there is not enough food to sustain a high predator population and thus predator death rate exceeds that of birth rate
- - - - Movement of alleles into and out of a population
      - Immigration
      - Emigration
      - Can be impeded by
      - Repercussions for
- - - - Orientation of bivalents is random
    - - Orientation of sister chromatids is random
    - - like in humans
  - - - Bet-hedging to novel environments
      - Multiple deleterious alleles can be bunched together and eliminated
      - genetic diversity
      - Escape host-parasite negative impacts
    - - Cross pollination vs
        Self pollination
- - - - Each individual has a unique genotype
      - Genotype is made up of alleles
      - Phenotypes determined by these alleles (and the environment)
      - There is no guarantee that an allele will manifest
      - Heterozygosity
      - The other gene has no discernable effect (recessive allele)
      - Homozygosity, both alleles are the same
    - - Alleles are segregated, separated, from one another during meiosis
      - Each gamete contains only one allele for each gene
      - Offspring inherit 2 alleles for a gene
      - During meiosis, 2 members of a gene pair separate from each other
      - Each gamete has an equal chance to inherit either one of the genes
    - - Gene pairs that are not related (homologs) segregate independently
      - Gene pairs that are not linked segregate independently
      - Evidence provided from a dihybrid cross
      - 3:1 phenotypic ratio for each of the 2 alleles
- - - - Deletion
      - Duplication
      - Inversion
      - Translocation
      - Transposons
    - - Change in one of the nucleic acids
      - Some are apparent in phenotype
      - Source of all new alleles
      - Must be in gametes to be inherited
  - - - Selfer
      - Outcrosser
  - - - Wheat
      - Result of sequential hybrid doubling and quadrupling
      - Original ancestral species had 14 chromosomes
      - Strawberry
      - Chemically induced
      - Prevent microtubule formation
      - Required for meiosis to occur properly
      - Produce diploid gametes
      - During fertilization 2 diploid gametes fuse
      - Results in tetraploid (4n)