Chromosome Numbers

• All animals have a characteristic number of chromosomes in their body cells called the diploid (or 2n) number.
• These occur as homologous pairs, one member of each pair having been acquired from the gamete of one of the two parents of the individual whose cells are being examined.
• The gametes contain the haploid number (n) of chromosomes.

(In plants, the haploid stage takes up a larger part of its life cycle - Link)

Diploid numbers of some commonly studied organisms
(as well as a few extreme examples)

Homo sapiens (human)	46
Mus musculus (house mouse)	40
Drosophila melanogaster (fruit fly)	8
Caenorhabditis elegans (microscopic roundworm)	12
Saccharomyces cerevisiae (budding yeast)	32
Arabidopsis thaliana (plant in the mustard family)	10
Xenopus laevis (South African clawed frog)	36
Canis familiaris (domestic dog)	78
Gallus gallus (chicken)	78
Zea mays (corn or maize)	20
Muntiacus reevesi (the Chinese muntjac, a deer)	23
Muntiacus muntjac (its Indian cousin)	6
Myrmecia pilosula (an ant)	2
Parascaris equorum var. univalens (parasitic roundworm)	2
Cambarus clarkii (a crayfish)	200
Equisetum arvense (field horsetail, a plant)	216

http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/C/Chromosomes.html