Charles Darwin, Evolutionary Thought,

1
Chapter 16

• Charles Darwin, Evolutionary Thought, the
  Evidence for Evolution

2
Theory of Evolution

• Common descent with modification
• Groups, species, or living things can modify in
  generations sometimes forming a new species
• All species descend from another species a
  single common ancestor
• Natural selection
• Organisms adapt to their environment be forming
  new traits, these traits are passed on to
  offspring survival of the fittest
• Organisms are continually changing
• Taller Redwood trees

3
Charles Darwin

• Credited for
• Descent with modification using evidence
• Descent with modification is caused by natural
  selection
• Alfred Wallace independently theorized natural
  selection and evolution

4
Darwin Background

• England
• Joined ministry at 20
• Joined voyage on HMS Beagle to survey coastal
  areas
• South American coasts
• Galapagos Islands

5
BEFORE Darwin

• Charles Lyell
• Earth was constantly changing
• Darwin thought then why not creatures?
• Jean-Baptiste de Lamarck
• Organisms changed form over generations through
  the inheritance of acquired characteristics
• Webbed toes
• Georges Cuvier
• Evidence of extinction of species
• All evidence that aided Darwin in his theory of
  evolution

6
AFTER Darwins Voyage

• Galapagos
• Collected data of creatures particularly finches
• Saw that the finches on Galapagos were related to
  finches on the South American coast
• Realized common ancestor on mainland but
  evolved on the island into a separate species
• Sparked connection between evolution natural
  selection
• Reading of book by Malthus

7
Alfred Wallace

• Studied bird and butterfly specimens on South
  American Southeast Asia
• Around same time as Darwin on his voyage
• Discovered natural selection shapes evolution
• Both papers (Darwin Wallace) were sent to
  scientific society meeting
• Influenced Darwin to write On the Origin of
  Species

8
Evidence for Evolution

• Radiometric Dating
• Aging of objects based on the decay of their
  radioactive elements (constant rate)
• Fossils
• Similarities differences
• Morphology Embryology
• Morphology study of physical forms
• Embryology study of fetal development
• Homologous structures in different organisms
• Gene Modification
• Variations found in DNA sequences of various
  organisms
• Experimental Evidence
• Lab evidence nature