Images Dated 28th July 2005

Portrait of Charles Darwin, British naturalist

Charles Darwin. Engraving of Charles Robert Darwin (1809-1882), British naturalist, in old age. Darwin studied medicine and theology, but his real interest was in natural history. In 1831, he joined the HMS Beagle as a naturalist on a five- year voyage around the world. This provided the data for his revolutionary book, On the Origin of Species by Means of Natural Selection (1859). In this work, he suggested that natural variation in a species creates a variety of individual traits, some more useful than others. Competition to survive causes favourable traits to survive and so a species evolves. His ideas were opposed by the Church, but have now largely been accepted

© VOLKER STEGER/SCIENCE PHOTO LIBRARY

Ball urchin

Ball urchin (Mespilia globulus) on a rock. This sea urchin inhabits reefs in the tropical Indo- Pacific area. It is generally nocturnal, hiding during the day and emerging at night to graze on algae. It is a small sea urchin, rarely exceeding six centimetres in diameter. Photographed in the Andaman Sea, Myanmar

© GEORGETTE DOUWMA/SCIENCE PHOTO LIBRARY

Whitemargin stargazer fish

Whitemargin stargazer (Uranoscopus sulphureus). This fish usually lies almost completely covered in sand, with only its upward-looking eyes visible. In this position it waits for prey, mostly smaller fish, to approach before engulfing it with a rapid strike. Some of the muscles in its head have been adapted into an electric organ capable of delivering a shock of up to 50 Volts. This is used to stun nearby fish. It also has two poisonous spines behind its head to deter predators. These can deliver a painful, if not fatal, wound to humans. It inhabits sandy reef bottoms in the tropical Indo-Pacific region, and can reach 45 centimetres in length. Photographed in the Egyptian Red Sea

© GEORGETTE DOUWMA/SCIENCE PHOTO LIBRARY