5 Evolutionary Mechanisms 9_3_09

5 Evolutionary Mechanisms 9_3_09 - 1 So what exactly is...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: 1 So what exactly is Darwins theory of natural selection? 2 Myth #1: Evolution is a theory about the origin of life 3 Darwin was not at all clear on how life itself originated I should infer from analogy that probably all the organic beings which have ever lived on this Earth have descended from some primordial form, into which life was first breathed From The Origin , ed. 1 I should infer from analogy that probably all the organic beings which have ever lived on this Earth have descended from some primordial form, into which life was first breathed by the Creator From The Origin , ed. 2 I should infer from analogy that probably all the organic beings which have ever lived on this Earth have descended from some primordial form, into which life was first breathed From The Origin , ed. 3 4 Darwin did believe that all organisms on Earth trace their origin to a single ancestor However, he was not at all clear on how life itself originated 5 John Gould, Ornithologist Darwin didnt know many of his samples were finches until an ornithologist figured it out 6 Myth #3 Galapagos finches were critical to the development of Darwins theory of evolution 7 Myth #4 Darwins Origin of Species documents numerous examples of natural selection in action. 8 Darwin observed extensive artificial selection 9 From a BBC program Whilst studying wildlife on the Galapagos Islands [Darwin] noticed that the Galapagos finches showed wide variations - eg in beak shape and size - from island to island. Darwin deduced that these differences made the finches better adapted to take advantage of the food in their particular local environment - thin, sharp beaks prevailing where the birds' main food was insects and grubs, and large claw-shaped beaks where their diet was buds, fruit and nuts. In each locality the finch population had somehow developed beaks which were suitable for that particular environment. Darwin concluded that in each locality one or more individual finch happened to acquire, by random mutation, a beak shape more suitable for the food sources in that locality. These individuals then had a competitive advantage over their fellow finches, enabling them to grow and reproduce more successfully, and pass on their more specialized beaks to successive generations - until eventually the characteristic had spread throughout the finch population in that locality. 10 Important Influences on Darwin Thomas Malthus Essay on Population (read by Darwin in 1838 after return) Human populations grow faster than their food supply Result widespread starvation, hardship Darwin extended these ideas to other organisms 11 Alfred Russell Wallace (1823-1913) Malay Archipelago Amazon of South America 12 Evidence for evolution 13 Darwin's theory of natural selection explained by evolutionary biologist Ernst Mayr implies that individuals with traits that better adapt them to a specific environment will survive and out number...
View Full Document

Page1 / 18

5 Evolutionary Mechanisms 9_3_09 - 1 So what exactly is...

This preview shows document pages 1 - 5. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online