ColorAcademy 2005

Biology - Flora & Fauna

Introduction

Many species of plants and animals use colour in relation to their environment in such a way that it attracts or warns, imitates or puts on camouflage.

Most of the colours of plants and animals are produced by pigments that absorb certain colours from light and reflect others. The principal pigment creating the greens of the flora is chlorophyll, which is crucial in the chemical process through which green plants make their food.

It absorbs the red rays of light that fall on it and uses the energy in the red light to synthesize molecular sugar from water and carbon dioxide. The light not absorbed but reflected by the chlorophyll is the green light that we see.

A pigment that plays a special part in creating the warm colouring of some animals is haemoglobin, which is chemically quite closely related to chlorophyll. It carries the blood through the bloodstream of animals causing some of the red, pink and brown colours of some animals. Orange colouration in animals and fish often comes from carotenoids, as in the gold of goldfish. Sepia and even melanin can tinge with ginger, orange and brown hues, as in colour of many birds beaks. The most brilliant blues, however, can be caused by interference phenomena, as in the morpho butterfly, dragonflies and peacock feathers. Black is usually produced by eumelanin.

D.P.

Bibliography

ADLER, R. (1962) Colour in your Life. London: Dobson. A popular science book with chapters on Nature.
ALLEN, G. (1882) The Colours of Flowers as illustrated in the British Flora. London: MacMillan Grant Allen's theories were approved by Charles Darwin. A small work illustrated with small line drawing.
BEDDARD, F. E. (1892) Animal Colouration. London: Swan and Sonnenschein. Frank Beddard was prosector to the Zoological Society of London and lecturer on biology at Guy's Hospital.The book has 4 coloured plates and 36 woodcuts.
DALE, J and GUNNELL, K. (1992) The Flower Colour Directory. London: Harper and Collins. A well-presented modern directory of flower colours.
FOX, F.M. and VEVERS, G. (1960) The Nature of Animal Colours. London: Sidgwick and Jackson. A good technical manual on the chemistry of animal colours, illustrated in colour with a synoptic appendix.
STEPHENSON, F.M. and Stewart, C. (1946) Animal Camouflage. Harmsworth: Penguin. An excellent work on the subject, but illustrated in black and white.
WILSON, R.F. (1938 and 1941) The Horticultural Colour Chart. Vols 1 and 2. London: Royal Horticultural Society. Is a dictionary of colours, each colour superbly reproduced.
Nature of Animal Colours. London: Sidgwick and Jackson. A good technical manual on the chemistry of animals.