Chromosomes are condensed spools of DNA. Most humans (there are rare exceptions) have 46 chromosomes; 23 they got from their dad and 23 from their mom. Chromosomes vary greatly between organisms. Below is a list of chromosomes in different organisms:
Common fruit fly - 8 chromosomes
Dove - 16
Domestic cat - 38
Gorillas - 48
Elephants - 56
Donkey - 62
Dog - 78
Goldfish - 100-104
The chromosomes hold the genes that provide our genetic makeup. They code for the color of our eyes, hair, height, any hereditary diseases, and much more.
There are 23 chromosomes in a grasshopper; 11 pairs and one "accessory" chromosome. The egg and sperm each have 11 chromosomes. Scientists believe the accessory chromosome serves special functions.
To really understand chromosomes and how they work, it would be best to take a tutorial or class.
Reference: http://ai.stanford.edu/~serafim/CS374_2005/Presentations/Lecture4_ClassicPapers.ppt
