Darwin Presents His Case Returning to England in 1836, Darwin began the process of cataloging his specimens’ and writing down the data he had collected on the 7 yr. voyage. Darwin was home and the scientific community was abuzz with talk of his work.

It was in England that Darwin found his various collection of birds from the Galapagos Island were all of the same species. Darwin had thought these birds were new species of wrens, Blackbirds warblers. and finches.

These Galapagos Finches were found nowhere else in the world These Galapagos Finches were found nowhere else in the world! The same was true of the tortoises

Darwin was filling notebooks with his work, but was reluctant to share publicly his ideas. He knew his work would be controversial and so he set out to completely prove his ideas before going public.

Years passed and he was still unsure if the public was ready Years passed and he was still unsure if the public was ready. Some of his findings were released and shorter papers printed. But he kept the major concepts to himself and a small group of friends. Then in 1859 Alfred Wallace sent him a letter…

Wallace working in Asia had come to similar conclusions as Darwin and was working a book. The proper pressure had been applied and Darwin completed his book in 18 months.

The concept of the theory in the book. Evolution by Natural Selection Struggle for Existence Survival of the fittest Descent with modification ( common descent)

Struggle for Existence Too many offspring will be born most will not survive. Those that live will be the best able to compete for resources.

Survival of the Fittest 1. Only the strongest and best competitors within a species will survive to reproduce. Decent with modification 2. Passing on characteristics thru reproduction. That will ensure the survival of the species. Over time the members of the species will change, they will better fit the environment in which they live.

Descent with Modification The most controversial of Darwin’s theory. In the beginning there were just cells Overtime natural selection Results in modifications to a Species (mutations) As organisms change they become more adapted to the environment in which they live.

Adaption Only offspring can adapt. You can’t, your children can Adaption Only offspring can adapt. You can’t, your children can. It is in being born with DIFFERENCES your parents don’t have that you adapt in the evolutionary sense.