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Botany Final, Extensions of Mendelian Principals, Genetic Drift, Nonrandom…

- - - - Resemble each other in size, shape & hereditary information
      - One homolog from ea parent
    - - Metaphase II
        Orientation of sister chromatids is random
      - Metaphase I
        Orientation of bivalents is random
    - - During Prophase I
      - Random new combinations result in nearly infinite different possibilities
      - Usually at least one chiasma
  - - - In Heterozygous individuals- 2 different alleles
        
        Dominant Alleles
        
        has a detectable effect on an organism's appearance
        
        Recessive Alleles
        
        May not effect appearance, masked by a dominant allele
      - Genotype is made up of alleles, These determine phenotype
      - In Homozygous individuals- 2 identical forms of an allele
        
        The allele present is expressed
      - Incomplete Dominance
        
        Phenotype of heterozygote is intermediate between those of parent homozygotes
    - - Alleles are segregated during meiosis, Each gamete has an equal chance to inherit either one of the genes
      - gamete contains only one allele
      - Offspring get one allele for the same trait from each parent
    - - Evidence provided from a dihybrid cross
        3:1 phenotypic ratio for each of the 2 alleles
      - Gene pairs that are not related (homologs) segregate
  - - - Considers two traits
    - - a cross between 2 parents. Considers one trait
    - - Genotypic ratio
      - Allele combinations
      - Phenotypic ratio
      - Trait combinations
- - - - S-shaped curve
      - Have a K: carrying capacity
      - dN/dt = rN[(K-N)/K] =
        rN(1-N/K)
  - - - J-shaped curve
      - Unlimited resources
      - dN/dt = rN
  - - - Most individuals die young
      - typical of r-selected species
    - - Most individuals survive until old age
      - typical of K-selected species
- - - - Allele frequency
        
        Number of copies of an allele in a population divided by the total number of 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
  - - - No new mutations #
        
        No genetic drift #
        
        No migration #
        
        No natural selection #
        
        Random mating #
      - When these exist. HW predictions will not match actual ratios
    - - q^2:
        
        Frequency of homozygous recessive individuals
      - 2pq
        
        Frequency of heterozygous individuals
      - p^2:
        
        Frequency of homozygous dominant individuals
    - - p= frequency of the dominant allele
      - q- frequency of the recessive allele
- - - - Stabilizing selection
        
        x0=x1
        var0>var1
      - Disruptive selection
        
        x0=x1
        var0<var1
      - Directional selection
        
        x0≠x1
        var0=var1