Explain Karyotype - Animal Taxonomy?

In animals systematic, it is the karyotype, that is the chromosome number and structure which are used quite extensively either separately or both together.

chromosome number as you know is quite constant within a species, though it may vary from one species to another even within the same genera. Among animals the chromosome number ranges from a diploid of 2 in Parascaris  equorum vat univalins to 446 in the lycaenid butterfly (Lysandra  arlantica). However, in most animals it is between 12-60 chromosomes.

figure: The phylogeny of Trichopternn families plotted on of chrmmme numbers (FhKiauia. 1%7).

Generally, the chromosome number is not enough for identifying organisms, though in some it has proved to be quite useful, as for example in the marsupial family Didelphidae (opossums) where species of genus (Monodelphis have a diploid number of 18 chromosomes and those of genus Didelphis have a diploid number of 22 chromosomes.

Similarly in the order of Trichoptera, the chromosome number alone has been used to plot the phylogenetic relationships among the various families as you can see in Figure.