Tuesday, January 24, 2012

Understanding Homology and Analogy

What is the difference between homology and analogy?

Some traits common between 2 individuals are inherited by a common ancestor, while others share traits through convergent evolution, a process where two or more different populations evolve a similar feature/characteristic separately from one another.


Traits, characteristics, or features inherited by a common ancestor.


~ Twins

~ Tetrapod limbs in humans, birds, whales, and lizards.

Similarity caused by convergent evolution, not by inheritance or common ancestry. Similarities between two distinct organisms caused by environmental changes.


~ Barnicles and Limpets (***Remember: Just because 2 organisms appear similar on the outside, does not mean that they are similar on the inside...)

~two elvis impersonators.

Inheriting Homologies


Marsupials Vs. Placentals

Marsupials: A mammal, such as a kangaroo, who cares for and protects their children within a maternal pouch.

Placentals: A mammal, including a human and elephant, whose young completes its embryonic development inside of the uterus. The embryo within the uterus is connected to the mother through a placenta.


Today in class we...

Completed Unit Packet page 11 and 12 (online activity).

~ Online activity can be accessed here: http://evolution.berkeley.edu/evolibrary/article/0_0_0/similarity_hs_01

Online Activity Covers:

-Homology, Analogy, Marsupials, Placentals, Similarities, and Evolution.

Lastly: Started Lab #38



Finish Lab #38

Course Rec. Sheet **Due Tomorrow**

Continue Reading Ch. 1, 13, and Charles Darwin Article

Unit Packet Page 5 **Due Monday**



**Next Scribe: Nazia


  1. Charles,
    Good job on your post. It was detailed and clear.
    But I think it would have been easier to read if the information was in bullet points and not full sentences.
    It was a good review though.

  2. Hey Charlie,

    This was a really clear and well organized post. I like your definitions, examples, and you also found good pictures! ;) The only thing was that the font after 'Inheriting Homologies' got obnoxiously large. But that could just be me. Other than that this was a really good post!

    -Eleni :)