Adventures in Evolution

1. Adventures in Evolution • http://www.youtube.com/watch?v=vmphlbRhLu8

3. HMS Beagle • Darwin did a 5-year voyage on the HMS Beagle • Darwin stated “ the voyage of the Beagle has been by far the most important event in my life and has determined my whole career”

5. Did Darwin invent the idea of evolution? • NO. But he is considered the father of evolution. • In 1830s people assumed that species were fixed and unchanging • Explorers and naturalists were discovery various plants and animals • Fossils were providing evidence of some species that lived in the past • Anatomists noticed physical resemblances between different species

6. Old ideas to explain how species changed were flawed • Lamarckianism, named after Jean-Baptiste Lamarck • Suggested that species could change through inheritance of acquired characteristics. • Giraffes developed their long neck by continually stretching them to feed on tall giraffes. • Once acquired, a giraffe could then pass on trait to its offspring

8. Charles Lyell • Darwin read the work by geologist Charles Lyell, “Principles of Geology” 1833. • Book argued that earth was much older than the 6,000 years • Incremental forces operating over a vast expanse of time

9. Darwin’s Voyage • Ideas of evolution really started when Darwin unearthed a complete fossil of a giant sloth embedded in a cliff, below a layer of seashells • Animal lived in the area before it was an ocean environment and had lived long time ago • No living animal in present day looked like the creature found. Where had they gone? • Reasoned that when the landscape changed the animals had been unable to adapt and became extinct. • Noticed that South American species resembled European ones, despite different environments

11. Darwin’s voyage • He evidence did not support a species perfectly adapted to its environment. • Galapagos Islands, observed small birds, finch • He realized that the birds were all closely related species of finch. – different size and shape of beak.

12. When he returned he read the a book by Thomas Malthus that described how hunger, starvation, and disease would ultimately limit human population growth (1798) • Limitation would lead to competition for resources • Favorable variations would be preserved and unfavorable ones destroyed • Competition, reproductive success would lead to a species becoming more adaptive to environment.

15. Natural Selection • Darwin’s original contribution to the theory of evolution he called descent with modification. • The mechanism of evolution is natural selection. • In 1844, Darwin developed his ideas into a 200 page manuscript

16. Alfred Wallace’s Thought • Wallace was also fascinated by natural history and adventure. • Was he rich? • He traveled to Brazil, to mouth of Amazon River • He also noticed different species of sloth monkey and other species. • What happened to his notes? • Wallace was able to write an article about new species but it did not mention a mechanism. • What happened to him next? • He worked out a mechanism of evolution and sent the paper to whom?

19. Darwin’s Book • Wallace stimulated Darwin to finish his book • Darwin finished his book on Evolution. • “On the Origin of Species by Means of Natural Selection” published in 1859