the main principals of heredity

Cards (20)

  • hereditary traits: traits that are transmitted from one generation to another
  • acquired traits: traits that arent inherited from parents, but are acquired through experience or environment
  • asexual reproduction: occurs by only one living organism by mitosis, the new indiviuals have the same genetic traits as the parent
  • sexual reproduction: occurs through two parents a male and a female
  • sexual reproduction depends on two main processes 1)formation of games 2)fertilization
  • genetics: is the science that researches the transmission of he hereditary traits from a generation to another
  • the scientist Mendel was the founder of heredity
  • mendel formed the experiment on pea plants because
    • easy to be planted and grows fast
    • its life cycle is short
    • its flowers are hermaphrodite ,so it can self pollinate
    • it can be easily artificially pollinated
    • it produces large numbers in a generation
    • it has several pairs of easily recognized contrasting traits
  • main traits for a pea plant:
    1. seed shape(smooth or wrinkled)
    2. fruit color(green or yellow)
    3. flower color(red or white)
    4. stem height(tall or short)
    5. seed color(yellow or green)
    6. fruit shape(swollen or sinuous)
    7. flower position(side or end)
  • the second generation is always 75%dominant : 25% recessive
  • the first generation is always 100% dominant
  • the principle of complete dominance :the appearance of a dominant trait in all the individuals of the first generation
  • hybrid individual :a person who carries a different or contrasting pair of genes one dominant and the other recessive
  • pure individual :a person who carries a similar pair of genes either dominant or recessive
  • Mendels first law is called "law of segregation of factors"
  • the recessive gene is always pure
  • hybrid x recessive = 50% dominant : 50% recessive
  • mendels second law is called "law of independent assortment"
  • when a tall stem red flower x short step white flower =
    • 9 tall stem red flowers
    • 3 short stem red flower
    • 3 tall stem white flower
    • 1 short stem white flower
  • dominant and recessive traits in humans:
    • curly hair : smooth hair
    • black hair : light hair
    • wide eyes : narrow eyes
    • dimples : no dimples
    • no freckles : freckles
    • ability to roll tongue : the inability to roll tongue
    • free earlobe : attached earlobe
    • dark eye : colored eye