AS Science for Public Understanding Evolution we (scientists) now accept that the diversity of life on Earth is explained by the theory of evolution by natural selection as proposed by Charles Darwin in 1859

AS Science for Public Understanding Evolution But Darwin was not the first to attempt to explain life each religion has its own creation story to account for life but the best “scientific” explanation prior to Darwin was that of… Jean-Baptiste de Lamarck in 1809 this theory is known as Lamarckism

AS Science for Public Understanding Lamarckism Lamarckism is always described using giraffes

AS Science for Public Understanding Lamarckism Lamarck noted that certain characteristics are advantageous such as the long neck of the giraffe which allowed giraffes to eat leaves from higher branches these leaves were out of the reach of smaller animals so long necked giraffes had an advantage

AS Science for Public Understanding Lamarckism Lamarck believed that giraffes stretched their necks during their life to reach the higher leaves just as a body builder expands her muscles during her life BUT Lamarck believed the giraffe was able to pass on this acquired characteristic (long neckedness) to its children

AS Science for Public Understanding Lamarckism evidence against Lamarckism: if Lamarck were correct and characteristics acquired during life could be passed on to the offspring then the babies of body builders would be…

AS Science for Public Understanding Lamarckism acquired characteristics are not inherited so Lamarckism was rejected

AS Science for Public Understanding Darwin when Darwin proposed his new theory he realised there was one major problem with it… time for evolution by natural selection to occur there had to be huge time periods available for natural selection to do its job

AS Science for Public Understanding Darwin until the middle of C19 –(19 th Century i.e. 1800s) it was thought that the Earth was quite young indeed a Christian scholar had calculated that the world was less than 6000 years old –(In the 17 th Century Bishop James Ussher calculated that creation occurred on 23 October 4004 BC)

AS Science for Public Understanding Darwin however, at about the same time as Darwin was observing finches in Galapagos Geologists such as Charles Lyell were looking at rocks… and fossils… and concluding that… the Earth was old… really, really old

AS Science for Public Understanding Darwin old enough to do this…

AS Science for Public Understanding Darwin …and this…

AS Science for Public Understanding Darwin …and this…

AS Science for Public Understanding Darwin current estimates put the Earth at 4,500,000,000 years old –4.5 billion with the first life dating to about 4 billion years ago for the first 3.5 billion years life was unicellular (essentially bacteria)

AS Science for Public Understanding Darwin many living near thermal vents

AS Science for Public Understanding Darwin others existing as large structures known as stromatolites

AS Science for Public Understanding Darwin then…. around 540 million years ago the Cambrian era began and the living world went absolutely screaming mental

AS Science for Public Understanding Cambrian Explosion

AS Science for Public Understanding Cambrian Explosion

AS Science for Public Understanding Cambrian Explosion

AS Science for Public Understanding Cambrian Explosion

AS Science for Public Understanding Cambrian Explosion

AS Science for Public Understanding Cambrian Explosion