Completed Mendelian genetics worksheet demonstrating a monohybrid cross between heterozygous gray and homozygous recessive black birds.

Let’s go step by step through each part of the worksheet to make sure everything is correct.

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Question 1a: Write the genotype of the female (left) below:

The problem says the female is heterozygous. That means she has two different alleles for the trait — one dominant and one recessive. We’re told to use B or b.

So, heterozygous = Bb

✔ Correct answer: Bb

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Question 1b: Write the genotype of the male (right) below:

The male is described as homozygous recessive. Homozygous means both alleles are the same. Recessive means they’re the lowercase version.

So, homozygous recessive = bb

✔ Correct answer: bb

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Question 1c: Which color is dominant, gray or black? How do you know?

We’re told the female is gray and her genotype is Bb (heterozygous). In genetics, if an organism shows a trait while being heterozygous, that trait must be dominant — because the dominant allele masks the recessive one.

Since the female is gray and has Bb, then gray is dominant, and black must be recessive.

Also, the male is black and bb — which fits: only when both alleles are recessive does the recessive trait show up.

✔ Correct answer:
The dominant color is gray since the female is gray and heterozygous (Bb).

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Question 1d: Write the phenotype of the female and the male below:

Phenotype = what you see (appearance), not the genes.

Female: genotype Bb → since B (gray) is dominant → phenotype = gray

Male: genotype bb → only recessive alleles → phenotype = black

✔ Correct answer:
(female) = gray (male) = black

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Question 1e: Complete the Punnett Square below for this couple:

Female gametes (top): B and b
Male gametes (side): b and b

Punnett Square:

```
| B | b |
-----------------------
b | Bb | bb |
-----------------------
b | Bb | bb |
```

Each box:
- Top-left: B from mom + b from dad → Bb
- Top-right: b from mom + b from dad → bb
- Bottom-left: B from mom + b from dad → Bb
- Bottom-right: b from mom + b from dad → bb

✔ So the filled square should be:

```
| B | b |
-----------------------
b | Bb | bb |
-----------------------
b | Bb | bb |
```

Which matches what’s written in the image.

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Question 1f: If they follow the Punnett Square ratios, what will the babies in the eggs look like when they hatch?

From the Punnett Square:

- 2 out of 4 = Bb → gray (since B is dominant)
- 2 out of 4 = bb → black

So ratio = 50% gray, 50% black

✔ Correct answer:
There is a 50% probability that the babies will look like gray and there is also a 50% probability that the babies will look like black.

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Question 1g: Will all four offspring adhere exactly to the ratios predicted by the Punnett Square? Explain:

Punnett squares give us probabilities, not guarantees — especially with small numbers like 4 offspring.

It’s like flipping a coin: even if heads/tails is 50/50, you might get 3 heads and 1 tail in 4 flips — it doesn’t have to be exactly 2 and 2.

Same here: each egg has a 50% chance of being gray or black, but with only 4 eggs, it’s possible (and likely!) that the actual outcome won’t match the exact 2:2 ratio.

The hint about flipping coins reinforces this idea — past results don’t force future ones, and small samples vary.

✔ Correct explanation:
No, since we cannot foretell something to come out exactly from the result of the ratio. The Punnett square is only for prediction; it is not 100% sure guaranteed that the answer from our solution will become the exact outcome.

*(Minor grammar note: “foretell” is okay, but “predict” is more common. Also, “our solution will become the exact outcome” could be smoother — maybe “the actual outcome will match the prediction.” But the meaning is clear and correct.)*

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All answers provided in the worksheet are scientifically accurate and logically sound.

Final Answer:
All parts of the worksheet are correctly answered as shown. No corrections needed.