Objectives 11.1The Work of Gregor Mendel-Survey Mendels studies and conclusions about inheritance.
-Examine what happens during segregation.
Lesson OverviewThe Work of Gregor MendelWhat is heredity?The delivery of characteristics from parent to offspring is called heredity.
The scientific study of heredity, known as genetics.
Lesson OverviewThe Work of Gregor MendelThe Experiments of Gregor MendelThe modern science of genetics was founded by Gregor Mendel.
Mendel used simple garden peas to demonstrate how traits are passed from one generation to the next.
Lesson OverviewThe Work of Gregor MendelSelf PollinationPea flowers are normally self-pollinating, which means that sperm cells fertilize egg cells from within the same flower.
True Breeding Lesson OverviewThe Work of Gregor MendelCross PollinationMendel decided to cross his stocks of true-breeding plantshe caused one plant to reproduce with another plant.
The offspring of crosses between parents with different traits are called hybrids.
Lesson OverviewThe Work of Gregor MendelThe GenerationsWhen doing genetic crosses, we call the original pair of plants the P, or parental, generation.
Their offspring are called the F1, or first filial, generation.
The offspring of the F1 generation are the F2, or second filial, generation. Lesson OverviewThe Work of Gregor MendelGenesFrom these results, Mendel drew two conclusions:
1. An individuals characteristics are determined by factors that are passed from one generation to the next.
Scientists call the factors that are passed from parent to offspring genes.
Lesson OverviewThe Work of Gregor MendelAllelesEach of the traits Mendel studied was controlled by one gene that occurred in two contrasting varieties.
The different forms of a gene are called alleles.
Lesson OverviewThe Work of Gregor MendelDominant vs Recessive Traits2. The principle of dominance states that some alleles are dominant and others are recessive.
An organism with at least one dominant allele for a trait will exhibit that form of the trait.
An organism with a recessive allele for a trait will exhibit that form only when the dominant allele for the trait is not present.
Lesson OverviewThe Work of Gregor MendelA capital letter represents a dominant allele.
A lowercase letter represents a recessive allele.
THEY MUST ALWAYS BE THE SAME LETTER.
Representing the Gametes
Lesson OverviewThe Work of Gregor MendelTrue or FalseA trait is a specific characteristic that can vary from one individual to another. _________________________
Lesson OverviewThe Work of Gregor MendelAnswersA trait is a specific characteristic that can vary from one individual to another. True
Lesson OverviewThe Work of Gregor Mendel