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Population, Screenshot 2025-05-05 at 9.58.59 PM, Screenshot 2025-05-05 at…

- - - - One paternal, One maternal
      - Homologous pairs #
    - - In general the possibilities are 2^n Ex: 2^46 = 7.04x 10^13
      - During Metaphase I
        Orientation of bivalents (Homologous pairs XX) is random
      - During Metaphase II
        Orientation of sister chromatids (X) is random
    - - During Prophase 1
        
        Touching parts of Homologous pairs can switch some genes and create Recombinants
    - - New combination of alleles from each parent
        Promotes heterozygosity
  - - - Dominance
        
        Each individual has a unique genotype (Alleles). Phenotypes are determined by the alleles.
      - Segregation
        
        Alleles are separated during meiosis
        
        Each gamete contains 1 allele for each gene
        
        Offspring inherits two alleles for a gene one from each parent
      - Independant Assortment
        
        Gene pairs that are not linked segregate independently
    - - Punnett square
        
        Visual representation of the offspring inheritance patterns
        
        Monohybrid is a cross between 2 homozygous parents with different alleles.
    - - Parental: True Breeding Homozygous
        
        F1: First Filial generation Heterozygotes
        
        Genotypic ratio-Allele Combinations
        
        Phenotypic ratio-Trait Combinations
  - - - Phenotype of heterozygote is intermediate between those of parent homozygotes
        
        Red + White=Pink
    - - Many populations have more than 2 alleles for a particular locus
        Breeding experiments to determine Dominance
    - - Changes in the genetic makeup of an individual
        
        Deletion, Duplication, Inversion, Translocation, Transposons
    - - Fail to mix alleles across homologs
        
        Chromosome inherited same as parent
        
        Only 2 gamete types possible rather than 4
    - - Multiple genes for one character
        Phenotype is cumulative result of combined effects of many genes
    - - One gene interacts with another
        May interfere or mask
    - - 4 haploid genotypes
        
        Not produced in equal numbers
        
        Recombinants less abundant
        
        Parentals more abundant
    - - Having more than two copies (2n) of a chromosome
        
        Autopolyploid
        
        Failed meiosis
        Self fertilization
        
        Allopolyploid
        
        Meiotic error-Mismatch during mating, second mating creates matched pairs
      - Example
    - - Single gene with multiple effects on the phenotype
        Inheritance of a single gene which visibly influences several traits
- - - - predicts an equilibrium-unchanging allele and genotype frequencies from generation to generation-if certain conditions exist in a population
      - No new mutations 2. No genetic drift. The population is so large allele frequencies do not change due to random sampling effects. 3. No migration 4. No natural selection 5. Random mating
  - - - Microevolution
        
        Non random mating
        
        Plants “choose” their mates
        
        Some of the individuals reproduce more than others
        
        Mutation
        
        Change in one of the nucleic acids
        
        Some are apparent in phenotype
        
        Source of all new alleles
        
        Polymorphism
        
        Dimorphic-2 phenotypes
        
        Dominant-recessive systems
        
        Polymorph = many phenotypes in a population
        
        Genetic Drift
        
        Random loss of alleles
        Acts most strongly in small populations relative to large
        Catastrophe
        
        Changes in a population’s gene pool from generation to generation
    - - Movement of alleles into and out of a population
      - Immigration-Into
      - Emigration-out of
    - - One allele selectively advantageous
        
        Over time, individuals with the 2 genotype are able to reproduce more and grow in numbers
      - Artificial Selection
        
        Selection by humans
        Increased frequency of desired trait
- - - - Population size (N)
        
        Exponential growth-J-shaped curve, unlimited resources
        
        Logistic growth-S shaped curve, typical of a population that has a carrying capacity and self regulates
        
        Carrying capacity (K)
  - - - To predict if a population will grow or shrink, ecologists need to know birth and death rates for organisms at different ages as well as the current age and sex makeup of the population. #
      - Life tables summarize birth and death rates for organisms at different stages of their lives.
      - Population age structure—Are there lots of: young individuals? Old individuals? Reproductive age individuals?; and similar questions
      - Population growth rate—How fast is the population size growing (or shrinking)? Population survivorship patterns—Does most mortality occur in the very young? The very old? Or equally across all ages?
  - - - a group of actually or potentially interacting species living in the same location.
    - - Range of interactions
        
        Beneficial interactions +
        
        Negative interaction -
        
        Examples
        
        Facilitation (+/+)
        
        Ex: Bee
        
        Commensalism 0/+
        
        Amensalism (0/-)
        
        Competition (-/-)
        
        Predation (+/-)
        
        Between Predator and prey #
    - - Predator
        
        P
        
        Negative impact on prey
      - Prey
        
        N
        
        Positive impact on Predator
      - Population sizes are influenced by each other