Most sexual organisms have two sexes. Sex determination in animals, is often accompanied by chromosomal differences. In other cases, sex is determined by environmental variables (such as temperature).
XX/XY sex chromosomes
In the XY sex-determination system, females have two of the same kind of sex chromosome (XX), while males have two distinct sex chromosomes (XY). Some species (including humans) have a gene SRY on the Y chromosome that determines maleness; others (such as the fruit fly) use the presence of two X chromosomes to determine femaleness.
ZW sex chromosomes
The ZW sex-determination system is found in birds and some insects and other organisms. The ZW sex-determination system is reversed compared to the XY system: females have two different kinds of chromosomes (ZW), and males have two of the same kind of chromosomes (ZZ).
Haplodiploidy
Haplodiploidy is found in insects belonging to Hymenoptera, such as ants and bees. Unfertilized eggs develop into haploid individuals, which are the males, while diploid individuals are generally female.
XX/XY sex chromosomes
In the XY sex-determination system, females have two of the same kind of sex chromosome (XX), while males have two distinct sex chromosomes (XY). Some species (including humans) have a gene SRY on the Y chromosome that determines maleness; others (such as the fruit fly) use the presence of two X chromosomes to determine femaleness.
ZW sex chromosomes
The ZW sex-determination system is found in birds and some insects and other organisms. The ZW sex-determination system is reversed compared to the XY system: females have two different kinds of chromosomes (ZW), and males have two of the same kind of chromosomes (ZZ).
Haplodiploidy
Haplodiploidy is found in insects belonging to Hymenoptera, such as ants and bees. Unfertilized eggs develop into haploid individuals, which are the males, while diploid individuals are generally female.
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1 comment:
your text need to be supported by some photos and figure in goal not to be boring
by the way what makes the female being just a carrier and not affected with some inherited diseases and syndromes , and not looks like the male .
is it propable to refer that to less genes of Y CHROMOSOME ?
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