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BOURNEMOUTH NATURAL SCIENCE SOCIETY | ||
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Given by: Donald Bradshaw OBE ARPS
This talk contributed to our 2009 programme of talks and events marking the 200th anniversary of Charles Darwin's birth and the 150th anniversary of the publication of 'The Origin of the Species'.
Donald Bradshaw is a great traveller and accomplished photographer who, on previous occasions, has spoken to the Society about Antarctica, Australia, India and Japan.
Today's talk was the result of three visits to Galapagos which, together with Madagascar, he considers 'musts' for the Natural Historian. 100,000 visitors annually are accompanied by Licensed Naturalists, as they explore these vulnerable volcanic islands. We saw lava flows, craters, pinnacles and eruptions as Donald explained their 5 million year evolution.
In 1835 Darwin visited at least four of the islands, collecting, observing and sending specimens back to England. Later he developed the Theory "That living things are not unchangeable or specifically created entities but are subject to evolutionary change by natural selection". The Darwin Research Centre continues his studies in situ today.
We heard about the climatic influence of the Humbolt Current, bringing penguins and cold Arctic water; of the El Ninio wind, periodically bringing heat that kills algae, fish and animals. Penguins are particularly sensitive to weather conditions - 70% died in 1983.
Endemic species of plants and animals include the Opuntia Cactus whose bark protects it from the ravages of grazing Giant Tortoises; the Sunflower tree Scalesia pedunculata, confined worldwide to one acre of one island; and Sea Iguanas whose evolved colouration camouflages the reptiles against attack by sharks.
And the birds!! Donald found them to be very approachable and was able to capture many memorable pictures. There were examples of the finches whose beak shape, varying with food supply and environment, set Darwin thinking.
Frigate Birds displayed their huge scarlet gular pouches, Boobies their blue or red feet, and Albatrosses their clumsy landing technique. Huge numbers of Waved Albatross were pictured on their nests on Hood Island. A nocturnal Swallow-tail Gull gazed out from its large ringed eye, while the flightless Galapagos Cormorant hung out stumpy wings to dry like its long-winged ancestor.
A Vermillion Flycatcher perched on the carapace of a Giant Tortoise brought this fascinating presentation to a close.
Many thanks, Donald, for sharing your insights and excellent photographs with the spellbound audience.