(i) Why are grasshopper and Drosophila said to show male heterogamity ? Explain.
(ii) Explain female heterogamity with the help of an example.

Explanation

(i) Drosophilia exhibit XY type of sex determination. Males produce two types of sperms, one having X chromosome and one having Y chromosome. Whereas females have only X-type of chromosomes. Grasshoppers exhibit XO type of sex determination. Males produce two types of gametes, one with X chromosome and other with no chromosome. Thus, both show male heterogamety.
(ii) Female heterogamety can be seen in female birds. In these, the females have one Z and one W chromosome whereas males have a pair of Z-chromosomes beside the autosomes.