Biology 11 Name __________________ Date: __________

Genes, Alleles and Traits(Use PowerPoint presentation to fill in your notes)

Key Vocabulary:

Trait (p264):

Gene (p265):

Allele (p265):

Types of Alleles:Dominant Allele:

Recessive Allele:

Genotype vs Phenotype (p268):

Genotype is

Phenotype is

A Punnet Square tool (p268) is used to determine ____________________________________________

______________________________________________________

It is named after Reginald C. Punnett, who devised the approach, and is used by biologists to determine the

probability of an offspring's having a particular genotype.

And, it can be used to determine if traits are:Homozygous (p268):

Heterozygous:

Practice: QuestionHow is a baby’s gender determined?

– If it has an ___ and ___ sex chromosomes, then it is a __________

– If it has two ___ sex chromosomes, then it is a ____________

Determining Probability Gender using a Punnett SquareJim and Sally are having a baby!

Determining Probability of Other Traits with Punnett SquaresJim has blonde hair (b). His genotype is (bb).Sally has brown hair (B). Her genotype is (Bb).

Types of Traits (p272 – 273):§ Monogenetic § Incomplete Dominance§ Codominance§ Multiple Alleles§ Polygenic

Monogenetic Trait : Definition

Examples

Incomplete Dominance : Definition

Examples

Codominance : Definition

Examples

Multiple Alleles : Definition

Examples

Polygenic Alleles : Definition

Examples

Where do the different alleles (and genes) come from??

There are 2 ways to get new genes:

1.

2.

Note: - Both result in the variation– AND Variation is necessary for evolution to occur. (We’ll talk more about variation & evolution in our next unit)

IMPORTANT NOTES:

The Variation is random. ____________________________ are determined by chance, not choice!!!So, the resulting variations also occur by __________________________.