Evidence for Evolution
Name: ______________________________ Period: ____
Part 1: Evidence from Anatomy
The picture below shows the forelimbs of mammals and how the bone structures are similar. Follow the
instructions for coloring and then answer the questions on the next page.
Coloring Instruction:



Scapula (A)- Red
Humerus (B)- Orange
Radius (C)- Yellow



Ulna (D)- Green
Carpals (E)- Blue
Metacarpals(F)- Purple

Phalanges (G)- Brown

Forelimb
- Grey
Part 1 Questions
1. Define homologous structure
2. What is the common function of all these forelimbs?
3. Describe 3 similarities in the structure of mammalian forelimbs.
4. How do these structures provide evidence to support the Theory of Evolution? (use at least 2
complete sentences to explain)
Part 2: Evidence from Embryology
The picture shows embryonic development of several animals. Use it to answer the questions below.
Eye
Gill
Slits
Tail
Part 2 Questions
5. At which stage is it the most difficult to tell the embryos apart? (I, II, or III)
6. Describe 3 similarities in the structure of these embryos.
7. How does embryological development provide evidence to support the Theory of Evolution? (use
at least 2 complete sentences to explain)
Part 3: Evidence from Biological Molecules
Examining the relationships between biological molecules, such as proteins or DNA can tell scientists
how closely related organisms are. The more similar these molecules are, the more recently the
organisms had a common ancestor. Follow the directions for each table.
Directions: There are 146 amino acids in the protein hemoglobin. This table shows a portion of the
amino acid sequence for hemoglobin for 6 different mammals. Circle or highlight the amino acids in the
chimp, gorilla, monkey, horse, and kangaroo sequences that differ from those in the human sequence.
Amino Acid #

Human
Chimp
Gorilla
Rhesus
Monkey
Horse
Kangaroo
Amino Acid #

Human
Chimp
Gorilla
Rhesus Monkey
Horse
Kangaroo
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
thr
thr
thr
leu
leu
leu
ser
ser
ser
glu
glu
glu
leu
leu
leu
his
his
his
cys
cys
cys
asp
asp
asp
lys
lys
lys
leu
leu
leu
his
his
his
val
val
val
asp
asp
asp
pro
pro
pro
glu
glu
glu
gln
leu
ser
glu
leu
his
cys
asp
lys
leu
his
val
asp
pro
glu
ala
lys
leu
leu
ser
ser
glu
glu
leu
leu
his
his
cys
cys
asp
asp
lys
lys
leu
leu
his
his
val
val
asp
asp
pro
pro
glu
glu
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
asn
asn
asn
asn
asn
asn
phe
phe
phe
phe
phe
phe
arg
arg
lys
lys
arg
lys
leu
leu
leu
leu
leu
leu
leu
leu
leu
leu
leu
leu
gly
gly
gly
gly
gly
gly
asn
asn
asn
asn
asn
asn
val
val
val
val
val
ile
leu
leu
leu
leu
leu
ile
val
val
val
val
ala
val
cys
cys
cys
cys
leu
ile
val
val
val
val
val
cys
leu
leu
leu
leu
val
leu
ala
ala
ala
ala
ala
ala
his
his
his
his
arg
glu
Directions: The table shows the number of amino acids in Cytochrome c that differ between several
organisms and humans. Cytochrome c is a protein found in mitochondria. It is often studied because
most organisms have mitochondria and therefore they have cytochrome c. Rewrite the information in the
blank table by listing the organisms IN ORDER with the greatest number of differences at the top and
the least at the bottom.
Species Comparison
# of differences
Human—chimp
0
Human—fruit fly
29
Human—horse
12
Human—pigeon
12
Human—rattlesnake
14
Human—red bread mold
48
Human—rhesus monkey
1
Human—screwworm fly
27
Human—snapping turtle
15
Human—tuna
21
Human—wheat
43
Species Comparison
# of differences
Part 3 Questions Use the Part 3 data tables to answer the questions below
8. On the basis of hemoglobin similarity, which organism appears to be most closely related to
humans?
least related?
9. On the basis of cytochrome c similarity, which organism appears to be most closely related to
humans?
least related?
10. “Horses and pigeons have a similar evolutionary relationship with humans.” Do you agree or
disagree with this statement
Describe evidence from the table to support
your claim
11. What could cause the differences in the amino acids sequences for the proteins in different
organisms?
12. If the amino acids sequences in the proteins of two organisms are similar, why will their DNA also
be similar?
13. Many biologists believe that the number of differences between the proteins of different species
indicates how long ago the species diverged from a common ancestor. Why do these same
biologists believe that humans, chimps, and gorillas diverged from a common ancestor only a few
million years ago?
14. If we looked at other proteins in the same organisms, would you expect to find roughly the same
amount of differences in the amino acid sequences?
Explain your answer.
Part 4: Evidence for Fossils
Fossil evidence provides the strongest evidence for evolution. Scientists believe that the ancestors of the
modern whale had once lived on land. Fossil evidence of transitional species supports this idea. On the
sheet labeled “Whales in the Making,” cut out the 6 whale ancestors and put them in order from oldest
ancestor (at the top) to most recent ancestor. The numbers they are labeled with do not give you any
clues, but be sure NOT to cut them off. Glue them on the last page of your packet.
Part 4 Questions
15. Summarize how the whale evolved from a land mammal (ancestor) to a marine mammal (modern
whale). Your summary only needs to describe the physical changes and you must write 3-5
complete sentences.
16. How does the fossil record provide evidence for evolution?
Part 5: Phylogeny
One way to discover how groups of organisms are related to each other (phylogeny) is to compare the anatomical
structures (body organs and parts) of many different organisms. Corresponding organs and other body parts that are
alike in basic structure and origin are said to be homologous structures (for example, the front legs of a horse, wings of
a bird, flippers of a whale, and the arms of a person are all homologous to each other). When different organisms share
a large number of homologous structures, it is considered strong evidence that they are related to each other. When
organisms are related to each other, it means they must have had a common ancestor at some time in the past.
When we do studies in comparative anatomy, and find different numbers of shared and derived (new) characters
exist between different groups, we can draw a diagram of branching lines which connect those groups, showing their
different degrees of relationship. These diagrams look like trees and are called "phylogenetic trees" or "cladograms".
The organisms are at the tips of the stems. The shared and derived features of the homologous structures are shown on
the cladogram. The more derived structures two organisms share, the closer is their evolutionary relationship -- that is,
the more recently their common ancestor lived. On the cladogram, close relationships are shown by a recent fork from
the supporting branch. The closer the fork in the branch between two organisms, the closer is their relationship.
A. Use the diagram on the right to answer the questions (17-22):
17. Which number represents the most recent common ancestor of taxa B and C?
18. Which number represents the most recent common ancestor of taxa A and B?
19. Is B more closely related to A or C?
20. Which number represents the most recent common ancestor of taxa C and D?
21. Which number represents the most recent common ancestor of taxa A and D?
22. Is C more closely related to B or D?
B. Use the diagram on the right to answer the questions (23-30):
23. Place an X where the common ancestor of all these
organisms would be on the diagram.
24. Which two organisms listed here are most closely
related?
25. Which two organisms listed here are least closely
related?
26. What is a derived character of the human?
27. What is a derived character of the rhesus monkey compared to the spider monkey?
28. What is a derived character of the spider monkey compared to the lemur?
29. What is a derived character of the chimp compared to the rhesus monkey?
30. List 2 shared characters of all the organisms in this diagram.
31. How does a cladogram illustrate evolutionary relationships?
WHALE EVOLUTION
WHALES IN THE MAKING
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