Objective: To understand how traits are passed on (heredity) Chapter 11.1

Genetics Genetics: study of heredity (how traits are passed on) Mendel: monk who studied pea plants and father of genetics Fertilization: male and female sex cells combine to make a new cell  make embryo

Fertilization Self-pollination: sperm and egg come from the same plant (pea plants typically do this) True-breeding: when they produce offspring they are identical to themselves (purebred) Ex: tall plants produce tall plants, short plants produce short plants

Mendel’s Research Mendel wanted to cross pollinate: sperm would come from one plant while egg comes from another. Mendel looked at traits: characteristic (height, color,)

Mendel’s Research The parent generation= P The offspring= F1 When Mendel crossed 2 true-breeding parents with different traits the offspring were hybrids Ex: Tall plant male and short plant female produce offspring with one tall allele and one short allele

Mendel’s research Mendel discovered: parents pass on genes (chemical factors that determine traits) And different forms of a gene are called alleles. Some alleles are dominant and some are recessive

alleles If an organism has a dominant allele the dominant trait is shown An organism has to have 2 recessive alleles for the recessive trait to be shown If an organism has both the dominant and recessive allele they will show the dominant trait, but they can pass on the recessive allele to their offspring. this is how traits can skip a generation

segregation When a parent forms gametes (sex cells) they only give one allele each (even though each parent has 2 alleles) When the parents alleles separate it is called segregation