Question

Which of the following is an example of ZW-ZZ Type of mechanism of sex determination?
A. Honeybee
B. Fish
C. Bird
D. Human being

Answer 1

Hint: Many people do an ultrasound to know the sex of their child. We human can learn the sex but in the animals, it all happens inside. The development of male or female depends on the gametes that are fertilizing. It takes time to know the sex of the progeny.

Complete answer:
Sex determination is the process of knowing the sex of the progeny. It takes place due to parental heterogeneity. The gamete fusing with each other decides the sex of the child. We come to know about the sex after 3-4 months (in humans) by ultrasound.

Let us see the mechanism of sex determination in the options.
> Option A. Honeybee: In honeybees, the males are haploids while the females are diploid. Males develop from the unfertilized eggs by parthenogenesis called arrhenotoky. Females develop from fertilized eggs so are diploid. Queen bees take sperm from the drone during nuptial flight and store in their vesicles.

> Option B. Fish: Fishes have a monogenic system of sex determination. The factors on the autosomal chromosomes decide on the sex of the new progeny.

> Option C. Bird: The birds have sex determination - ZZ-ZW that is ZZ is male which is homogametic whereas ZW is female which is heterogametic. So the female gametes decide the sex of the offspring. The total number of chromosomes remains the same in both male and females.

> Option D. Human being: In humans, the female is homogametic that means it has XX part of a chromosome whereas the male is heterogametic having XY. So the sex of the offspring depends on the heterogenicity of the male.

Hence, The correct answer is option (C).

Note: Sex determination in India is banned. When people came to know about the sex of the child, they usually aborted the girl child as they think it to be a burden. The ultrasound is the process which helps to know the sex of the child in the 4-5 month. The fetus develops heartbeat in the 2nd month of gestation. The limbs of the fetus start to develop by the end of the 2nd month.