Which of the following organisms do not show male heterogamety ?

Options

A. hens
B. humans
C. fruit flies
D. grasshoppers

Answer

To solve the question "Which of the following organisms do not show male heterogamety?", we need to understand the concept of male heterogamety and analyze the given options.

### Step-by-Step Solution:

1. **Understanding Male Heterogamety**:
- Male heterogamety refers to the condition where males produce two different types of sex chromosomes. For example, in humans, males have one X and one Y chromosome (XY), while females have two X chromosomes (XX). This means males are heterogametic (XY) and females are homogametic (XX).

2. **Analyzing the Options**:
- We need to evaluate each organism provided in the options to determine if they exhibit male heterogamety.

3. **Option 1: Birds**:
- In birds, males have two Z chromosomes (ZZ), while females have one Z and one W chromosome (ZW). Here, the males are homogametic (ZZ), and females are heterogametic (ZW). Therefore, birds do not show male heterogamety.

4. **Option 2: Humans**:
- In humans, males have one X and one Y chromosome (XY), which means they are heterogametic. Therefore, humans do show male heterogamety.

5. **Option 3: Fruit Flies (Drosophila)**:
- In fruit flies, males have one X chromosome and no second sex chromosome (XY), while females have two X chromosomes (XX). This indicates that males are heterogametic. Thus, fruit flies do show male heterogamety.

6. **Option 4: Grasshoppers**:
- In grasshoppers, males have one X and no second sex chromosome (XO), while females have two X chromosomes (XX). This means that grasshoppers also exhibit male heterogamety.

7. **Conclusion**:
- After analyzing all options, we find that the only organism that does not show male heterogamety is **Option 1: Birds**.

### Final Answer:
The correct answer is **Option 1: Birds**.