Chemotaxonomy also called chemosystematics, is the attempt to classify and identify organism

Organism

In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

s (originally plant

Plant

Plants are living organisms belonging to the kingdom Plantae. Precise definitions of the kingdom vary, but as the term is used here, plants include familiar organisms such as trees, flowers, herbs, bushes, grasses, vines, ferns, mosses, and green algae. The group is also called green plants or...

s), according to demonstrable differences and similarities in their biochemical

Biochemistry

Biochemistry, sometimes called biological chemistry, is the study of chemical processes in living organisms, including, but not limited to, living matter. Biochemistry governs all living organisms and living processes...

 compositions. The compounds studied in most of the cases are mostly protein

Protein

Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

s, amino acid

Amino acid

Amino acids are molecules containing an amine group, a carboxylic acid group and a side-chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen...

s and peptide

Peptide

Peptides are short polymers of amino acid monomers linked by peptide bonds. They are distinguished from proteins on the basis of size, typically containing less than 50 monomer units. The shortest peptides are dipeptides, consisting of two amino acids joined by a single peptide bond...

s. Examples of chemotaxonomic markers are phospholipid-derived fatty acids

Phospholipid-derived fatty acids

Phospholipid-derived fatty acids are widely used in microbial ecology as chemotaxonomic markers of bacteria and other organisms.Phospholipids are the primary lipids composing cellular membranes. They can be esterified to many types of fatty acids...

 and enzymes.

E.G. Family Rutaceae can be distinguished by the presence of oil glands; Families Aschepiadaceae and Apocyanaceae can be differentiated based on the presence of latex.

Chemosystematics can be viewed as a hybrid science that complements available morphological data
to improve plant systematics.

John Griffith Vaughan

John Griffith Vaughan

John Griffith Vaughan was a Welsh food scientist. He was an expert in seed science, whose work linked the fields of botany and nutrition....

was one of the pioneers of chemotaxonomy.