DARWIN and WALLACE

DARWIN -well off -well educated -young & energetic -careful note taker -lots of time to observe

HMS BEAGLE

HMS Beagle. -5 year trip around the world -Darwin as gentleman companion and then as a naturalist -stopped at many places in South America

Travelled down the east coast of South America Noted pattern of life changing as he went south found giant fossil species that resembled current species there

GALAPAGOS ISLANDS -volcanic islands 1600 km from South America -very few land animals present; all of which arrived recently

Each island had mockingbirds with slightly different beaks and feeding habits

                                                                                                                      

Darwin’s Finches: each had different bills & different diets.

The giant tortoises on each island had slightly different shells and ate slightly different plants.

A zoo in Australia has held a 175th birthday party for Harriet the tortoise, one of the world's oldest known living creatures, a Giant Galapagos tortoise. Testing has suggested the giant creature was born around 1830, a few years before Darwin visited the Galapagos archipelago in 1835. Harriet died in 2006.

Darwin back in England -did more research on collected specimens for the next 20 years [1835-1855] -every Royal Navy vessel that landed on the Galapagos was required to collect finches & note where they were shot. -he was afraid of his own theories as they related to the church

tree finches #8 - 13 warbler finch woodpecker finch ground finches # 1 - 6

Woodpecker finch chooses different cactus spine for each job a large cactus spine a small cactus spine

A small population of ground finches have found a new source of food… A small population of ground finches have found a new source of food….blood from large birds These are called vampire finches Ground finches with a booby

GALAPAGOS FINCHES -each island has unique finches -finches beaks match their diet -mainland only has one finch -DARWIN thought that diet may have helped select or shape the beaks of the finches

As Darwin thought, and experimented back in England, Alfred Russell Wallace was busy at work during the 1850’s in Brazil Unfortunately, all of his collected materials were destroyed when his boat sank in 1852 Others would have given up, Wallace just went off to Indonesia to start again

WALLACE -not well off -sold specimens he collected -careful observer mostly “BIRDS OF PARADISE” -careful observer -visited islands

Bird of Paradise worth quite a bit as a preserved specimen

Wallace’s journey

What Wallace observed Sailing 1000km from Java to Bali, saw only hornbills eating large fruit with big seeds After crossing 32km of ocean, at Lombok, saw only cockatoos eating large fruit with big seeds

Remember you can see Lombok from Bali Wallace wondered: why had God had created two such different birds to eat the same large fruit on two islands that were right beside each other? Wallace concluded: the environment had selected the best Asian bird [the hornbill] and the best Australian bird [the cockatoo] to match the same fruit

Wallace’s Line

Darwin and Wallace in 1855

DARWIN / WALLACE Each concluded: -environment somehow shapes species -species vary due to natural selection

NATURAL SELECTION Darwin & Wallace were both influenced by: Malthus – ESSAY ON POPULATIONS KEY IDEA – more births occur than can be supported so only the ‘fit’ survive

WALLACE wrote to DARWIN -they shared similar theories -DARWIN was afraid WALLACE would scoop him -they agreed to publish a joint paper 1855

DARWIN published a book: 1859 “On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life.”

The book was greeted with much criticism and ridicule, The book was greeted with much criticism and ridicule, especially cartoons, although Darwin never mentioned humans at all in his book. Mr. Darwin, sir!

“The Origin of Species” Reaction to “The Origin of Species”

Darwin fled to his country house and would see no visitors Thomas Huxley was a friend who agreed to speak for Darwin. He became known as “Darwin’s Bulldog” because he loved to argue about evolution [with anyone]

Evolution had won its first trial. It would face many more There was a famous evolution debate on June 30, 1860 between Huxley and Bishop Wilberforce. Bishop Wilberforce was winning the debate until he strayed into Human Evolution. At some point he challenged Huxley about his ancestry. Huxley responded that “I would rather be descended from an ape than from a pompous ass like you!”. And the audience ended the debate with applause for Huxley. Evolution had won its first trial. It would face many more

Now back to the giraffes….how would Darwin explain the longer necks?