Question

Identify the incorrect pair regarding sex determination systems:

• A. XX-XO type – Grasshopper
• B. ZZ-ZO type – Drosophila
• C. ZZ-ZW type – Birds
• D. XX-XY type – Human beings

Hint:

Recall that different species can have different mechanisms for sex determination, which are crucial for understanding genetic and evolutionary biology.

Answer 1

The Correct Option is B

Step 1: In Grasshoppers, the XX-XO type of sex determination is found. In this system, females have two X chromosomes (XX), and males have only one X chromosome (XO). The presence or absence of the second X chromosome determines the sex of the offspring. Step 2: In Drosophila (fruit flies), the XX-XY sex determination system is used, not ZZ-ZO. In this system, females have two X chromosomes (XX), and males have one X chromosome (XY). The sex of the offspring is determined by the presence of the X and Y chromosomes. Step 3: In Birds, the ZZ-ZW type of sex determination is found. In this system, males have two Z chromosomes (ZZ), and females have one Z and one W chromosome (ZW). The female's W chromosome determines the sex of the offspring. Step 4: In Humans, the XX-XY type of sex determination is present. This system is similar to Drosophila in that females have two X chromosomes (XX), and males have one X and one Y chromosome (XY). Conclusion: The incorrect pair is (2) ZZ-ZO type — Drosophila. Drosophila uses the XX-XY sex determination system.