Chapter 5

Mendel’s Work

Gregor Mendel’s work allowed us to understand why plants and animals are the way they are.

Hereditary is the passing of physical characteristics from parents to offspring.

Mendel’s work continue

Why do some people have blue eyes while others have brown eyes.

Why are some plants tall and some short.

Mendel studied pea plants to learn about traits.

Trait is a characteristic that organisms can pass on to offspring through its genes.

Mendel’s work continue

Mendel experimented by breeding different type of plants together.

These studies founded the studies of genetics.

Genetics is the scientific study of hereditary.

What did he learn Every trait has different genes and

alleles. Genes are a set of information that

controls a trait. Alleles are the different forms of a gene. Alleles can be dominant or recessive Dominant means a trait that always

shows up in the organisms Recessive means a trait is hidden when

the dominant allele is present.

Recessive and Alleles

Each gene has two traits. Dominant genes are labeled with a

capital letter like B and recessive genes are labeled with a lowercase letter like b.

A gene can look 3 different waysBBBbbb

How do we know what color eyes you have We figure out the possibility of what

color eyes you will have by filling out a punnett square.

A punnett square is a chart that shows all the possibility combinations of alleles that can result from a genetic cross.

Punnett Square

Genes

Phenotypes is the physical appearance or visible trait.

Genotypes is the genetic make up or allele combinations.

Homozygous organism has two identical Alleles such as BB or bb

Heterozygous organism has two different Alleles such as Bb.