1. Warm-Up (1/19)
Answer the following questions, and explain in a complete sentence why each answer is correct.
What does the term “biomagnification” mean? Look at “Biomagnification” notes, page 7.
When organisms grow larger.
When poisons or toxins become more concentrated in the food chain.
When scientists observe living samples under a microscope.
When organisms begin to shrink.
How many alleles does one gene have?
Name
Date
Period

2. Genetics Each gene makes a protein, which causes a trait.
Different alleles cause different traits.
Example: eye-color gene
Blue allele makes blue eyes
Brown allele makes brown eyes
Eye-color gene
Eye-color gene
Blue allele
Brown allele

3. bb Bb BB Genetics Recessive alleles show traits only when homozygous.
Dominant alleles show traits when homozygous OR heterozygous. bb
homozygous recessive Bb
heterozygous BB
homozygous dominant

4. bb Bb BB Genetics Genotype – which alleles you have (example: Bb)
Phenotype – which trait you have (example: brown eyes) bb
homozygous recessive Bb
heterozygous BB
homozygous dominant

5. Genetics
The first generation is called P, then F1, then F2.

6. Example
In dogs, wire hair (S) is dominant to smooth (s). In a cross of a homozygous wire-haired dog with a smooth-haired dog, what will be the phenotype of the F1 generation? S S s Ss Ss s Ss Ss

7. Dihybrid Cross Practice
Carousel Activity
Only 5 questions!
Dihybrid Cross Practice
In the flower-color gene, purple flowers (P) is dominant to white flowers (p).
In the seed-texture gene, round seeds (R) is dominant to wrinkled seeds (r).
Do a dihybrid cross between two plants which are heterozygous for the flower-color gene AND the seed-texture gene.

8. Closure
Answer the following question in a complete sentence:
Name
Date
Period
If blue eyes is recessive for eye color, is a blue-eyed person homozygous or heterozygous for the eye-color gene? How do you know?
Scale from 1-10