AP Notes, Outlines, Study Guides, Vocabulary, Practice Exams and more!

Darwin's Theory of Evolution

Charles Darwin - wrote On the Origin of Species  

  • contemporaries believed that species were unchangeable, structures made due to will of the Divine Creator
  • proposed that natural laws produced change/evolution over time
  • never challenged the existence of a Divine Creator
  • based his ideas on studies in S America and Galápagos Islands
  • didn't publish his results for 16 years until Alfred Russel Wallace submitted similar theory independently
  • The Descent of Man - argues that humans and apes have similar ancestors

Darwin's evidence - from expeditions to the Americas  

  • fossils of extinct armadillos found in the same area where similar armadillos lived
  • 14 species of finches on the Galápagos Islands all had different beaks from eating different food, but otherwise very similar
  • resemblances in plants in close areas, not similar climates

Thomas Malthus - wrote Essay on the Principle of Population  

  • pointed out that human population grew geometrically, but food supply grew arithmetically
  • only death prevents populations from growing out of control
  • his ideas made Darwin realize that only organisms w/ superior attributes survive

natural selection - survival of the fittest; environment only allows the best fit to survive  

  • artificial selection - breeders selecting specific organisms to pass along desired characteristics
  • organisms ill-suited for the environment die out; their attributes don't get passed on

evidence of evolution after Darwin - more support for evolution has come up since his time  

  • fossil record - goes back 2.5 billion years; shows how organisms changed from simple to complex
  • age of the earth - estimated to be 4.5 billion years; people of Darwin's time thought the earth was only a few thousand years old
  • genetics - explains how new variations occur in organisms
  • comparative anatomy - limbs and appendages of different organisms containing the same type of bones
  • homologous bones - have same evolutionary origin, but have different uses
  • analogous bones - have similar structure but different evolutionary origins
  • molecular evidence - more closely related organisms have less differences in DNA
  • molecular clock - constant change that occurs to proteins over time
  • phylogenetic tree - pattern of descent that maps out the history of an organism
Subject X2: 

Need Help?

We hope your visit has been a productive one. If you're having any problems, or would like to give some feedback, we'd love to hear from you.

For general help, questions, and suggestions, try our dedicated support forums.

If you need to contact the Course-Notes.Org web experience team, please use our contact form.

Need Notes?

While we strive to provide the most comprehensive notes for as many high school textbooks as possible, there are certainly going to be some that we miss. Drop us a note and let us know which textbooks you need. Be sure to include which edition of the textbook you are using! If we see enough demand, we'll do whatever we can to get those notes up on the site for you!