Download Access the following link:

Name __________________ Class Period ___ Date _______
Similarities and differences: understanding
homology and analogy
Access the following link:
http://evolution.berkeley.edu/evolibrary/article/similarity_hs_01
Directions: As you move through the website, complete the following:
Define the following in your own words:
Biological Similarities:
Common Ancestor:
Homology:
Analogy:
Convergent Evolution
Play the short game: The tale of the limb
Note two similarities between the four limbs shown.
a. _______________________________________________________________________________
b. _______________________________________________________________________________
The tetrapod limb
Name the species that go with each of the four tetrapod limbs shown.
a. ____________________________
c. ____________________________
b. ____________________________
d. ____________________________
Look at the four species shown. What other similarities exist between these four animals?
a. ____________________________
c. ____________________________
b. ____________________________
d. ____________________________
1 | Homologies and Analogies
Inheriting homologies
How do such different animals wind up with the same sort of limb?
a. ________________________________
How many years have passed since the single common ancestor lived?
b. _______________________________
What are structures that are inherited from a common ancestor called?
c. _______________________________
Homologies are everywhere
Name three homologous structures.
a. ___________________________________
b.___________________________________
c.___________________________________
Not all similarity is homology
Look at the evolutionary tree shown. Explain why the octopus limb and the vertebrate limbs are not
homologous.
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
__________________________________________________________________________________
2 | Homologies and Analogies
Analogies
Read the information provided. Look at the first cladogram. Notice the characteristic dot with the information
(common ancestor with canine teeth) printed beside it. The grey dot is placed at the top of the vertical line
and at the T of the divergent line. On this cladogram both marsupials and placental animals inherit canine
teeth.
Read the information about the second cladogram. Notice the location of the characteristic dots. The dots
indicate homologous and analogous structures.
Name one homologous structure and the four species that inherit the structure:
Homologous Structure: __________________________________________________________
a. __________________b. ____________________c. ________________d. ____________________
Name one analogous structure and the two species that inherit the structure:
Analogous Structure: _________________________
a. _________________________ b. _______________________
How do analogies evolve?
On the diagram above, insert the following characteristic dots:
Cartilage- ( hint- place this dot at the top of a T )
Bones- (hint- place this dot at the top of a T)
Use the internet, or your own knowledge to place characteristic dots on the cladogram that are responsible
for the divergence of separate species.
Test your own understanding
Are wings of sugar gliders and flying squirrels homologous or analogous? ________________
3 | Homologies and Analogies