This document outlines several key pieces of evidence that Darwin used to support his theory of evolution by natural selection: Biogeography and his observations from the Galapagos Islands showed that isolated populations can diverge over time. Experiments introducing non-native species to islands like Hawaii demonstrated they can thrive. Homologous and analogous features, as well as vestigial structures, provide evidence that species share common ancestors. Competition within populations for limited resources means favorable traits will be selected for, driving evolutionary change over generations. Together, these various forms of evidence helped validate Darwin's revolutionary theory of evolution by natural selection.

1. The Evidence for
Evolution

2. Darwin’s Voyage – BBC 2009
• Part 1:
• http://www.youtube.com/watch?
v=ZtZb6GZgniI
• Part 2:
• http://www.youtube.com/watch?
v=xGAVnbSW6kQ&feature=related

3. Evidence for Evolution
• Types of evidence Darwin used to support his
theory:
– Biogeography
– Homologous and analogous features
– Vestigial features
– Competition within populations

4. Biogeography + Darwin’s Observations

5. Key Observation from Galapagos
Islands

6. Testing Darwin’s Hypotheses:
Hawaiian Islands

7. Testing Darwin’s Hypotheses
• When non-native
mammals and
amphibians introduced
to islands, they have
been able to thrive.
This eliminates the
possibility that they
can’t survive on remote
Dodo Bird Extinction within 175
islands.
years – Mauritius Islands
(Indian Ocean)

8. Homologous Features
• Structures with common evolutionary
features which serve different functions in
modern species
•
Video on homology: http://www.youtube.com/watch?v=XgXT9sU6y18&feature=related
http://www.xspore.com/community/drama/6876-evolution-vs-religion-4.html

9. Analogous Features
• Structures that perform same function in two
species but are not similar in origin or
anatomy

10. Vestigial Features
• Features that no longer serve the function
they do in similar species
http://paxarcana.wordpress.com/2009/08/25/your-appendix-mayactually-do-something/
http://rebeccamcc.blogspot.com
/
http://www.youtube.com/watch?
v=lBkiT0zyYm0

11. Competition Within Populations
• Thomas Malthus (Principle of Population)
showed that all population are limited in size by
the environment (food supply)
Darwin’s thoughts:
• All species produce more offspring than can
survive to reproduce
• This results in competition for resources
between members of the same species
• Environment might be favouring certain
individuals

12. Homework 
• Page 303 # 1,2,4-7