Thomas Thomas MalthusMalthus

1798 published 1798 published Essay on the Essay on the Principle of PopulationPrinciple of Population Gave Darwin idea that populations produce Gave Darwin idea that populations produce

more offspring than can survive because more offspring than can survive because populations increase faster than earth can populations increase faster than earth can support support

This would mean that natural selection would This would mean that natural selection would be “the survival of the fittest” because there be “the survival of the fittest” because there were not enough resources for every organism were not enough resources for every organism to survive. to survive.

LamarckLamarck LamarckLamarck published a published a

theory of evolutiontheory of evolution in in 1809 (same year Darwin 1809 (same year Darwin was born). He explained was born). He explained the mechanism of the mechanism of evolution with two evolution with two principles.principles.

The The use or disuse of body use or disuse of body parts leads to their parts leads to their development or development or deteriorationdeterioration, , acquired acquired characteristics can be characteristics can be inheritedinherited..

Charles Lyell Charles Lyell Proposed geological theory of Proposed geological theory of

uniformitarianism which is different from uniformitarianism which is different from catastrophism.catastrophism.

Uniformitarianism- the events in the past Uniformitarianism- the events in the past that formed the Earth are still at play that formed the Earth are still at play today and are a gradual processtoday and are a gradual process

Principles of Geology Principles of Geology was published, was published, Darwin read and agreed with the findings.Darwin read and agreed with the findings.

Charles Lyell ContinuedCharles Lyell Continued He studied sedimentary rock and how the He studied sedimentary rock and how the

layers (stata) of the Earth form.layers (stata) of the Earth form. He said that these processes take thousands He said that these processes take thousands

of years to occur.of years to occur. Darwin used this information to conclude that Darwin used this information to conclude that

if the different layers of the Earth take if the different layers of the Earth take thousands of years to form, then the different thousands of years to form, then the different fossils found in each layer must’ve taken fossils found in each layer must’ve taken thousands of years to change or evolve. thousands of years to change or evolve.

Charles Lyell Cont.Charles Lyell Cont.

Voyage of the BeagleVoyage of the Beagle

Darwin was 22 years old when he sailed from Darwin was 22 years old when he sailed from Great Britain on the Great Britain on the H.M.S. Beagle H.M.S. Beagle in 1831.in 1831.

He spent the voyage collecting thousands of He spent the voyage collecting thousands of specimens of the fauna and flora, observing specimens of the fauna and flora, observing various adaptations of organisms. He was various adaptations of organisms. He was particularly struck by the uniqueness of the particularly struck by the uniqueness of the fauna of the fauna of the Galapagos IslandsGalapagos Islands

Darwin and WallaceDarwin and Wallace In the 1830’s Darwin starts compiling his In the 1830’s Darwin starts compiling his

work and another scientist, Alfred Wallace, work and another scientist, Alfred Wallace, was also working on a theory of natural was also working on a theory of natural selection.selection.

Before publishing his findings, Wallace sends Before publishing his findings, Wallace sends a copy of his work to Darwin in 1858.a copy of his work to Darwin in 1858.

To Darwin’s surprise, Wallace has formulated To Darwin’s surprise, Wallace has formulated a very similar theory!a very similar theory!

Both findings were presented to the Linnaean Both findings were presented to the Linnaean Society in 1858.Society in 1858.

Darwin’s Darwin’s Origin of Species Origin of Species was published in was published in 1859 (yes! 20 years after he wrote it!), 1859 (yes! 20 years after he wrote it!), Wallace will continue his travels and research Wallace will continue his travels and research

Wallace’s theory and name will forever stand Wallace’s theory and name will forever stand in the shadow of Darwin and the theory of in the shadow of Darwin and the theory of evolutionevolution

Best Seller!Best Seller! Darwin’s book was a success, however, Darwin’s book was a success, however,

natural selection was still questioned even natural selection was still questioned even by Darwinistby Darwinist

In 1865 Mendel’s findings on heredity were In 1865 Mendel’s findings on heredity were publishedpublished

However, it would take until the 1900’s However, it would take until the 1900’s before the findings were revisitedbefore the findings were revisited

Charles Darwin dies in 1882 and is buried in Charles Darwin dies in 1882 and is buried in Westminster AbbeyWestminster Abbey