Question

What type of sex determination is found in grasshopper?
a. XX-XY
b. ZW-ZZ
c. ZZ-ZY
d. XX-XO

Answer 1

Hint: Sex determination is a process of determining the sexual characteristics developed in any organism. There are two types of sexes present i.e. male and female. Generally, any one of these two sex organ is present in an organism that reproduces sexually. Some organisms may have both type of sex organs present in them, and are called hermaphrodites.

Complete answer:
Most of the times, the sexual morphology of males and females are different as they have different alleles or genes for sex determination. In animals, sex determination is done on the basis of differences in chromosomes. There are four basic combinations found, these are XX-XY, ZX-ZZ, ZZ-ZO, and XX-XO.

The sex determination in grasshopper is found to be of XX-XO type. In this type, females have two copies of the sex chromosome represented by XX, while the males have only one copy of the sex chromosome and can be represented as XO. Here, the O shows the absence of second sex chromosome. When X chromosome from female, fuses with X chromosome of male, a female offspring is produced. And when X chromosome from female, fuses with no chromosome of male, then a male is produced having chromosomes XO. This method depends upon the amount of genes expressed between the two chromosomes.
This system can be seen in many insects such as grasshoppers, cockroach, crickets etc.

Hence, the correct answer is option (D).

Note: XX-XY system is observed in humans where females have XX chromosomes and males have XY chromosomes.
The ZW-ZZ system is observed in moths and butterflies in which males are homogametic having ZZ chromosomes while females are heterogametic having ZW chromosomes.
The ZZ-ZO system is seen in some months where males have two Z chromosomes (ZZ) while the females have only one Z (ZO).