01b evidence of evolution (7.4)

The Evidence for Evolution

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

Evidence for Evolution

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

Biogeography + Darwin’s Observations

Key Observation from Galapagos Islands

Testing Darwin’s Hypotheses:Hawaiian Islands

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 islands. Dodo Bird Extinction within 175

years – Mauritius Islands (Indian Ocean)

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

Analogous Features

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

Vestigial Features

• Features that no longer serve the function they do in similar species

http://rebeccamcc.blogspot.com/

http://paxarcana.wordpress.com/2009/08/25/your-appendix-may-actually-do-something/

http://www.youtube.com/watch?v=lBkiT0zyYm0

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

Homework

• Page 303 # 1,2,4-7