1. Thurs. Bellwork
In rabbits, black fur is dominant over white fur. Describe the genotype and phenotype of these rabbits:
BB Bb bb
Ifc:

2. Types of Dominance
SC.7.L.16.1
I can describe types of dominance because I can identify examples of each

3. What are some types of Dominance?
complete dominance -
If one allele is dominant and the other is recessive the dominant allele covers up the other and determines the phenotype. (how the trait looks)
For example – in rabbits, if Black(B) is dominant over white (b)
BB = black
bb = white
Bb = black - because the dominant allele (B) covers up the recessive allele (b) 3

4. What are the exceptions to complete dominance?
incomplete dominance
each allele in a heterozygous individual influences the phenotype.
You get a phenotype that is a blend of the phenotypes of the parents.
Examples:
In some types of flowers, neither trait is dominant so you get a combination of the 2.
R = Red W = White RW = Pink 4

5. 2. codominance, both of the alleles contribute to the phenotype.
You can see both of the traits associated with the 2 alleles
BB – blue fish
RR – red fish
BR – spotted fish – you can see both the
red and blue traits in the offspring
Human blood type is an example of codominance. Three alleles play a role in determining blood type. A, B, and O
Blood types can be A, B, AB, or O 5

6. Identify as incomplete dominance or co dominance – explain how you know:
A mouse can be black, white, or gray
Birds can be blue, white, or white with blue wings
A sneech can be tall, medium, or short

7. What else can influence phenotype?
acquired traits - the environment can influence an organism’s traits. They are not inherited
examples
your ability to read and write
Short hair
Good at sports
Ability to play the drums 7

8. Turn and Talk: 1 minute then share with class:
List 3 inherited traits you have
List 3 acquired traits you have

9. Summary: What is the difference dominance, co-dominance, and incomplete dominance? Write it in the summary section

10. In complete dominance, one trait takes over the other
In complete dominance, one trait takes over the other. In incomplete dominance the two traits blend, in co dominance both traits are shown. HW: complete ws on back of notes sheet.

11. Friday Bellwork
1. What is the difference between incomplete and complete dominance?
2. A brown horse and a white horse cross to produce an offspring that is brown and white spotted. What pattern of dominance is this?
IFC