In humans, males are heterogametic and females are homogametic. Explain. Are there any examples where males are homogametic and females heterogametic ?

Explanation

(a) The term homogametic and heterogametic refer to the organism depending upon whether all the gametes contain one or same type of sex chromosome (Homo = same) or two different types of sex chromosomes (Hetero = different).
= (i) Humans show XX/XY type of sex determination, i.e. Females contain two copies of X chromosome and males contain one X and one Y chromosome. (ii) Therefore, ova produced by females contain the same sex chromosome, i.e. X. (iii) On the other hand the sperms contain two different types of chromosomes, i. e. 50% sperms have X and 50% have Y chromosome open from half the autosomes (Meiosis). Therefore, the sperms are different with respect to the composition of sex chromosome.
= In case of humans, females are considered as homogametic (XX). Males are considered as heterogametic (XY). Yes, there are examples where males are homogametic and females are heterogametic. In some birds the mode of sex determination is denoted by ZZ (males) and ZW (females)