Genetics worksheet using characters from SpongeBob SquarePants to teach dominant and recessive traits, with handwritten solutions.

Let’s work through this step by step.

We’re told:
- SpongeBob is heterozygous for square shape → that means his genotype is Ss (since square is dominant, and heterozygous = one dominant, one recessive allele).
- SpongeSusie is round → round is recessive, so her genotype must be ss.

Now we set up a Punnett square:

SpongeBob’s alleles: S and s
SpongeSusie’s alleles: s and s

Punnett Square:

| | s | s |
|-------|-------|-------|
| S | Ss | Ss |
| s | ss | ss |

So the possible offspring genotypes are:
- Ss (square shape) — appears in 2 out of 4 boxes
- ss (round shape) — appears in 2 out of 4 boxes

That means:
- 50% chance of square shape (Ss)
- 50% chance of round shape (ss)

Now let’s answer each part:

A. Possible genotypes: Ss and ss
Possible phenotypes: Square shape and round shape

B. Chances of square shape: 2 out of 4, or 50%

C. Chances of round shape: 2 out of 4, or 50%

Final Answer:
A. Genotypes: Ss, ss; Phenotypes: Square, Round
B. 2 out of 4, or 50%
C. 2 out of 4, or 50%