Dominant & Recessive Human Traits

Students will be able to analyze traits in the population. Objective Students will be able to analyze traits in the population. Everyone has traits that they inherit from their parents. Each parent sends one allele for each gene. The offspring has a unique combination of traits depending on what is passed down from their parents. We will be looking at traits that only have one dominant and one recessive trait and follow the Law of Dominance. If the person is homozygous dominant, the dominant trait will be shown. If the person is heterozygous, the dominant trait will be shown. If the person is homozygous recessive, the recessive trait will be shown. You will be observing the phenotype. In the future, we will discuss genotypes.

Trait: A variation of a phenotypic characteristic Vocabulary Review Trait: A variation of a phenotypic characteristic

Part of the chromosome that is the unit of heredity. Vocabulary Review Gene: Part of the chromosome that is the unit of heredity. Allele: Alternative forms of a gene

Vocabulary Review Dominant Trait: The trait that always appears in the phenotype if the dominant allele is present in the genotype. (Homozygous dominant or heterozygous organism).

Vocabulary Review Recessive Trait: The trait that appears in the phenotype only if two recessive alleles are present in the genotype. (Homozygous Recessive)

Vocabulary Review Homozygous: An organism with two of the same alleles for a specific gene. Heterozygous: An organism with two different alleles for a specific gene.

Vocabulary Review Phenotype: An organism’s observable trait or characteristic Genotype: An organism’s two allele pair for each gene

Human Traits: Tongue Rolling or Not

Human Traits: Free or Connected Earlobes

Human Traits: Widow’s Peak or Straight

Human Traits: Hitchhiker’s Thumb or Straight

Human Traits: Cleft Chin or not

Human Traits: No Dimples or Dimples

Human Traits: Freckles or No Freckles

Human Traits: Interlaced Fingers LEFT Thumb over RIGHT Thumb RIGHT Thumb over LEFT Thumb

Activity: Sample the Class for Traits Each group will be assigned a set of traits to survey the class sample. You will total the number of people with each trait. Circle the trait that had the most representation in the class.

Trait 1: # of Classmates with Trait Trait 2: Tongue Rolling   No Tongue Rolling Free Earlobes Connected Earlobes Straight/ No WP Widow’s Peak Hitchhiker Thumb Straight Thumb Cleft Chin Flat/No Cleft Chin Dimples No Dimples Freckles No Freckles Interlaced: Left Interlaced: Right

Dominant: Tongue Rolling or Not

Dominant: Free or Connected Earlobes

Dominant: Widow’s Peak or Straight

Dominant: Hitchhiker’s Thumb or Straight

Dominant: Cleft Chin or not

Dominant: No Dimples or Dimples

Dominant: Freckles or No Freckles

Dominant: Interlaced Fingers LEFT Thumb over RIGHT Thumb RIGHT Thumb over LEFT Thumb