Station 1 –Homologous and
Analogous Structures
1.
Compare the Meaning of the terms “homologous and analogous”
 Use Figure 1 to complete the table on your student answer sheet.
2.
How are the body parts of the limbs of each of the animals illustrated the same and different?
3.
Does the similarity in bone structure suggest common ancestry amongst these animals?
 Use Figure 2- to complete the table on your student answer sheet
4.
5.
6.
What function do the butterfly and bird wings share?
In what ways do the structures differ?
Explain why these are considered analogous and homologous structures?
Figure 1
Figure 2
Station 2 –Vestigial Structures
Thinking Critically- Examine the examples of vestigial structures and determine what
each vestigial structure may suggest about the organism’s evolutionary past.
7.
How do vestigial structures provide evidence of an organism’s evolutionary past?
Station 3 –Embryology
Examine the Figure Carefully-Describe how the embryos changed for each of
these organisms from their earliest to latest stages.
Species
Anatomical Changes From Early to Late Stages
Human
Chicken
Rabbit
Tortoise
Salamander
Fish
8.
9.
Describe the patterns you see. What physical similarities exist between each of the embryos?
Does this suggest an evolutionary relationship? Explain how these embryos can be used as
evidence of a common ancestor between each of these six organisms?
Station 4 -DNA Sequences
Differences
Goal: Infer relationships among animals by comparing DNA nucleotides of homologous genes.
The diagram shows a small portion of the DNA for the gene, Hoxc8 for three animals-a mouse, a baleen whale,
and a chicken.
 Count the nucleotides in one entire sequence.
 Then count the nucleotides in the whale DNA that differ from those in the mouse DNA
 Divide the number of nucleotides that are different by the total number of nucleotides, and multiply by 100.
Analyze and conclude
10. What percentage of the nucleotides in a baleen whales DNA are different from those of a
mouse?
11. What percentage of the nucleotides in the chicken are different from those of the mouse?
12. Do you think a mouse is more closely related to a baleen whale or to a chicken?
13. Do you think that scientists can use small sections of DNA, like the ones shown here, to infer
evolutionary relationships? Why or why not?
Station 5 –Fossil Record
 Locate the Whale Skeletons Cards
 Sequence the whale skeleton cards in order from the oldest fossil to the
most recent skeleton.
 Justify your answer in the chart
14. What do the fossil remains of earlier whales indicate about changes in the whale’s habitat
over time?
15. Based on observations of the whale skeletons, what can you tell about their evolutionary
history to the present day whale?
Directions: Cut out the Images of the Whale Skeleton and place them in an envelope.
Rodhocetus kasrani
Station 6 –Biogeography
The Galapagos Islands are home to giant tortoises that feed on green vegetation. Originally, tortoises lived only on Isabela Island and
had dome-shaped carapaces, or shells (see figure 1). Isabela has a relatively wet climate and varied plant life.
Today tortoises are found on the other islands as well. On the small islands such as Española, there are tortoises that have a
'saddleback' carapace (see figure 2). The 'saddleback' carapace is elevated above the neck and flared above the hind feet. On the
small islands the climate is drier and there is almost no ground vegetation. Prickly pear cactus (a major source of food and water for
the 'saddleback' tortoises) has a tree-like form.
Figure 1
Doomed Tortoise
Figure 2
Saddle backed Tortoise
16. Why does the doomed tortoise have a short neck and the saddle back tortoise have a long neck?
17. Why do these tortoises of the same species look different?
18. Based on the tortoise distribution on the Galapagos Islands, is their evidence to support they share a
common ancestor? Explain your answer.
Figure 1
Doomed Tortoise
Figure 2
Saddle backed Tortoise