Flashback Meisosis• Cell division that

produces four cells (Gametes), each with half the number of chromosomes as the parent cell.

• “CROSSING OVER” occurs during Prophase I

• Are any Gametes alike?• What science deals with

heredity and genetic variations?

GENETICS- study of heredity: the branch of biology that deals with heredity and

genetic variations

Gregory Mendel (1822-1884)

• Augustinian monk who taught natural science to high school students

• described how traits were inherited by observing pea plants

• +30 years for the scientific community to “catch up” with his findings

Gregor Mendel, who is known as the "father of modern

genetics“.

Pea Plants

Plants also undergo mitosis and meiosis as do most living organisms.

Pea Plants

Gregor Mendel noticed many differences among pea plants, which got him thinking.•What observations do you notice about the pea plants listed above?

Botany- is a branch of biology that involves the scientific study of plant life

• Mendel was a botanist and loved to cross plants.

• His observations allowed him to notice a significant outcome.

• What do you notice?

• What color are the pea plants when purple flowers are crossed with white?

• Answer Purple • What color occurs

when you cross their offspring?

• Purple and White• WHY?

Traits must be passed down from parents!

CA State Standards

Genetics 3 A multicellular organism develops from a single zygote, and its phenotype depends on its genotype, which is established at fertilization. As a basis for understanding this concept:

b) Students know the genetic basis for Mendel's laws of segregation and independent assortment.

Human Karyotype46 Total Chromosome

50% from MOM

Female

XX

50% from DAD

Male

Xy

Mendel’s Laws1st Law- The law of segregation-

According to the law of segregation, the genetic characteristics of a species are represented in the somatic cells by a pair of units called genes that separate during meiosis so that each gamete receives only one gene for each trait.

46 chromosomes get divided into 23 (Gametes= Egg or Sperm)!

n = One set of chromosomes

Somatic = Human Body Cells

2nd LawThe law of independent assortment- states

that alleles of different genes assort independently of one another during gamete formation. That traits are transmitted to offspring

independently of one another.

Larger picture on next slide

The End