Pea experiment:
Which traits did he look at?:
· Form of ripe seed (R) – smooth or wrinkled
· Colour of seed albumen (Y) – yellow or green
· Colour of flower (P) – purple or white
· Form of ripe pods (I) – inflated or constricted
· Colour of unripe pods (G) – green or yellow
· Position of flowers (A) – axial or terminal
· Length of stem (T) – tall or dwarf
Mendelian Law:
Law of segregation (1st Law): Every individual contains a pair of alleles, which can separate during cell division. Each parent passes a randomly selected copy to its offspring.
Law of independent assortment (2nd Law): The separate genes for separate traits are passed independently of one another from parents to offspring
Law of dominance (3rd Law): Recessive alleles will always be masked by dominant alleles
What did he do?:
Over many generations Mendel selectively crossbreed common pea plants and like this discovered common traits.
Discovered the blending theory: Believed inherited traits were determined randomly
Blending theory is wrong, as it would assume that a specific trait would constantly decrease, e.g. height. A tall parent and short parent would give a medium sized offspring and this offspring would also give even shorter children, as its height is the upper and lower bound. If this was true, height would decrease from generation to generation.
It can also be not allocated randomly because sometimes all generations have a common trait, e.g. brown hair.
Which traits did he look at?:
· Form of ripe seed (R) – smooth or wrinkled
· Colour of seed albumen (Y) – yellow or green
· Colour of flower (P) – purple or white
· Form of ripe pods (I) – inflated or constricted
· Colour of unripe pods (G) – green or yellow
· Position of flowers (A) – axial or terminal
· Length of stem (T) – tall or dwarf
Mendelian Law:
Law of segregation (1st Law): Every individual contains a pair of alleles, which can separate during cell division. Each parent passes a randomly selected copy to its offspring.
Law of independent assortment (2nd Law): The separate genes for separate traits are passed independently of one another from parents to offspring
Law of dominance (3rd Law): Recessive alleles will always be masked by dominant alleles
What did he do?:
Over many generations Mendel selectively crossbreed common pea plants and like this discovered common traits.
Discovered the blending theory: Believed inherited traits were determined randomly
Blending theory is wrong, as it would assume that a specific trait would constantly decrease, e.g. height. A tall parent and short parent would give a medium sized offspring and this offspring would also give even shorter children, as its height is the upper and lower bound. If this was true, height would decrease from generation to generation.
It can also be not allocated randomly because sometimes all generations have a common trait, e.g. brown hair.