Which molecule is responsible for the wide diversity of life on earth?

A phylogeny is an evolutionary "tree" of related

organisms that can be constructed by using

information obtained from the genetic material.

Genetic information is contained in all living cells,

in the form of long DNA molecules that take the

shape of connected double - stranded spirals

(DNA stands for deoxyribonucleic acid). DNA

spirals, or "helixes", are tightly compressed in the

nucleus of every cell. Their information is

organized into a code made up of four small

molecules - the building blocks of DNA. The

molecules, called nucleotides, are labelled:

A (adenine), C (cytosine), G (guanine) and T

(thymine).

It is possible to draw conclusions about the

evolution of a group of plant or animal species,

and the relationships among them, by comparing

selected pieces of DNA.