in humans male determine the sex of a child,,but in bird not?? why??
Please find below the solution to the asked query
In humans male determine the sex of a child but not in birds because humans posses male heterogamy and birds have female heterogamy.
Humans posses male heterogamy. In human beings, the females have XX sex chromosomes and the males have XY sex chromosomes. Hence, males produce two type of gametes X and Y while females produce only one type of gamete with X chromosome. The sex of the child depends on type of male gamete (sperm) fertilising female gamete (egg). When sperm with X chromosome fuses with egg, the child will be female and when sperm with Y chromosome fuses with egg, the child will be female. Hence in humans male determines sex of child.
Birds have female heterogamy. In birds, males have same sex chromosomes (ZZ) and females have different sex chromosomes (ZW). Hence, females produce two type of gametes Z and W while males produce only one type of gamete with Z chromosome. The sex of the chick depends on type of female gamete (egg) fusing with male gamete (sperm). When egg with Z chromosome fuses with sperm, the chick will be male and when egg with W chromosome fuses with sperm, the chick will be female. Hence, in birds female determines sex of chick.
Hope this information will clear your doubts about the sex determination in humans and birds.
If you have any more doubts just ask here on the forum and our experts will try to help you out as soon as possible.
Regards