The main reason for classifying living things : to make it easier to study them
Past methods for classification : studying the morphology (the overall form and shape of thei bodies) and the anatomy (the detailed body structure, usually determined by dissection)
NEW method for classification : study of DNA
DNA - the chemical from which our chromosomes are made... the genetic material, passed on from one generation to the next
Each DNA molecule is made up of strings of smaller molecules, containing 4 different bases (called A, C, G and T). These bases can be arranged in any order.
Biologists can compare the sequences of bases in the DNA of organisms from two different species. The more similar the base sequences, the more closely related the species are to one another.
The similarities in sequences of amino acids in proteins can be used in the same way.
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