Name ____________________________________________ Block - ____________ Date ___________________
Lab: Evidence for Evolution
Use the information in each section, combined with what is in your notes to answer the following questions.
PART I: STUDYING FOSSILS (structure & age):
There is an enormous amount of evidence that supports the theory of evolution. Much of this evidence is found in the
rocks of the Earth itself.
o James Hutton & Charles Lyell proposed a theory that stated that the Earth is ancient and has been shaped
by the same natural geological forces that are still at work today (theory of uniformitarianism).
o Lyell also argued that scientists must always explain past events in terms of events and processes they can
observe themselves.
Below, you will see how paleontologists use radioactive dating to find out the age of a fossil. Fossils are the preserved
remains of ancient organisms.
o The approximate age (relative age) of a fossil can be determined through relative dating. This technique is
based on the fact that new layers of rock are deposited on top of older layers of rock.
o Relative Age is based on the Law of Superposition (proposed by Nicholas Steno in the 1600s).
1. In which layer would you find the oldest fossil? _______________
2. In which layer would you find the youngest fossil? ____________
3. If each layer represented a one of the four Eras, which layer could
A
B
contain fossils from the Cenozoic Era? ______________________
4. Which layer might contain fossils from the Paleozoic Era? ______
C
5. Which layer might contain fossils from the Mesozoic Era? ______
6. Which layer might contain fossils from the Precambrian Era? ____
D
7. If some of the fossils found in layer C are found to be about 50 million years
old, what at the very least can you say about the age of the fossils found in layer B? Explain your answer.
________________________________________________________________________________________
________________________________________________________________________________________
8. What can you say about the fossils found in layer D? Explain your answer.
________________________________________________________________________________________
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Part II: BIOCHEMICAL COMPARISIONS
Red blood cells make large amounts of an iron-containing protein called hemoglobin. The purpose of hemoglobin (a
red pigment) is to transport oxygen throughout your body to your cells.
 Examine the amino acid sequences below which compare corresponding portions of hemoglobin molecules in
humans and five other vertebrate animals.
 The sequence shown is only a small portion of the chain of 146 amino acids that make up the protein. The
numbered columns indicate the position of each amino acid within the whole chain.
Use the information found in Table A (below) to complete the following steps:
Step 1: Look at each numbered column (). Put an X in the blank under each column in which all six animals have the same
amino acid.
o An X should not be put below column 87 since between the six animals; there are 4 different amino acids in that column.
o An X is placed below #88 since all six animals have the same amino acid in this spot.
How many of the columns have the same amino acid for all six animals? _______________________________
Step 2: Look at the numbered columns in which there are amino acids that are different than the human’s. Circle the amino acids
in each column that are different from the human amino acid in the same column.
Table A: Comparing hemoglobin of a human to other organisms.
Amino Acid # 87
88 89 90 91 92 93 94 95 96 97
Humans
Chimpanzee
Gorilla
Rhesus monkey
Horse
Kangaroo
THR
THR
THR
GLN
ALA
LYS
LEU
LEU
LEU
LEU
LEU
LEU
SER
SER
SER
SER
SER
SER
GLU
GLU
GLU
GLU
GLU
GLU
LEU
LEU
LEU
LEU
LEU
LEU
HIS
HIS
HIS
HIS
HIS
HIS
CYS
CYS
CYS
CYS
CYS
CYS
ASP
ASP
ASP
ASP
ASP
ASP
LYS
LYS
LYS
LYS
LYS
LYS
LEU
LEU
LEU
LEU
LEU
LEU
HIS
HIS
HIS
HIS
HIS
HIS
98
99 100 101
VAL
VAL
VAL
VAL
VAL
VAL
ASP
ASP
ASP
ASP
ASP
ASP
PRO
PRO
PRO
PRO
PRO
PRO
# of
Differences
GLU
GLU
GLU
GLU
GLU
GLU
____ _X_ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____
Table A: (continued)
102 103 104 105 106 107 108 109 110 111 112 113 114 115 116
Humans
Chimpanzee
Gorilla
Rhesus monkey
Horse
Kangaroo
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 GLY
LEU GLY
LEU GLY
LEU GLY
LEU GLY
LEU 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
# of
Differences
HIS
HIS
HIS
HIS
ARG
GLU
____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____ ____
Step 3: In the FAR RIGHT column of the table (top and bottom), identify how many amino acids were circled for
each row.
1. To identify how many total differences of amino acids each of following organisms had when compared to the
human amino acid, you will need to add the numbers from the top and bottom table for each animal.
How many amino acids in each animal’s hemoglobin are different from a human’s hemoglobin.
a. Chimpanzee ______________
b. Gorilla __________________
c. Rhesus monkey ___________
d. Horse ___________________
e. Kangaroo ________________
2.
Based on the information from table A & question 1, which organism is most closely related to humans? ________________
3.
Based on the information from table A & question 1, which organism is least closely related to humans? _________________
4.
If we were to run a DNA fingerprint on all six animals listed above and then compare them, what might we expect to find?
_____________________________________________________________________________________________________
5.
To make these DNA fingerprints, would we want to use part of an organisms DNA that is highly variable between two
animals of the same species, or parts that are very similar for the same species? Explain. _____________________________
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_____________________________________________________________________________________________________
Cytochrome C is an ancient protein thought to have developed early in the evolution of life. Since this essential
protein performs a key step in the production of cellular energy, it has changed little in millions of years. So,
you can look into yeast cells or plant cells or our own cells and find a very similar form of cytochrome C.
 The following table shows the number of amino acid differences in cytochrome C between a human and ten other
organisms. Use this information to answer the questions in this section. GRAPH this information below.
Table B: Cytochrome C differences
1. On the basis of cytochrome C evidence, what organisms
Organism
# of diff.
appear to be most closely related to humans?
Human – Human
0
_______________________________________________
Human – Chimpanzee
Human – fruit fly
Human – horse
Human – pigeon
Human – rattlesnake
Human – red bread mold
Human – rhesus monkey
Human – screwworm fly
Human – snapping turtle
Human – tuna fish
Human – wheat
0
29
12
12
14
48
1
27
15
21
43
2. Which organisms appear to be least related to humans?
_______________________________________________
3. Which two organisms appear to be equally related to
humans? _______________________________________
4. Is it possible for the organism from the question above to be
equally related to humans but not equally related to each
other? _________________________________________
1. There is a difference of only one amino acid in one chain of the hemoglobin of humans and gorillas. If humans
and Gorillas shared a common ancestor, then what might have caused them to have that one difference in their
hemoglobin (hint: it is the raw material for evolution)? ______________________________________________
2. Is it this one difference that makes humans and gorillas different species? Explain. ________________________
____________________________________________________________________________________________
3. If we know that the amino acid sequences in the proteins of two organisms are similar, why should we expect their
DNA to also be similar (hint: what is the connection between proteins and DNA)?
___________________________________________________________________________________________
__________________________________________________________________________________________
4. 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 scientists believe that humans,
chimpanzees, and gorillas diverged from a common ancestor only a few million years ago (on an evolutionary
scale, this is considered to be recent)?
_____________________________________________________________________
_____________________________________________________________________
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PART III: COMPARATIVE EMBRYOLOGY
1. How does studying the images to the right helps support the theory of evolution?
Explain what the images to the right are suggesting.
____________________________________________________________________
____________________________________________________________________
____________________________________________________________________
2. Based upon what you learned in the part II, what animal embryo would we expect to
most closely resemble the human (one that is not shown)? ______________________
PART IV: COMPARATIVE ANATOMY (Structure & function)
1. If the internal structure of the above forelimbs (front appendages) looks so similar, why then has the outside
evolved with such different variations?
___________________________________________________________________________________________
___________________________________________________________________________________________
2. What is the term for structures (such as the ones seen above) that have a common origin? ____________________
3. What type of evolution is responsible for the development of the above structures? _________________________
4. Even though the three animals on the right evolved from different ancestors, they appear to have a similar body
design? What type of evolution would cause this to occur? ____________________________________________
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5. What caused these three animals to have such similar appearances? _____________________________________
____________________________________________________________________________________________
6. What word is used to describe similar structures that evolved from different origins? ________________________
o The idea that snakes evolved from four legged animals similar to lizards is not new.
o Most species of snakes have lost all traces of limbs but snakes in the boa and python family have a
tiny pair of hind legs (sometimes called pegs).
o The python's (or boa's) evolutionary history with legs can actually be seen as a pair of "spurs" that
stick out where the body ends and the tail begins.
7. Since these ‘legs’ no longer serve any function and have shrunk to a size where they are no longer useful, they are
classified as __________________________ structures. In other words, they are homologous structures that have
lost their purpose.
8. In humans the __________________________ is also classified as this type of structure since it appears to also
have shrunk and currently does not seem to serve a function.
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PART V: SHOWING EVOLUTIONARY RELATIONSHIPS
Sometimes when looking through the fossil record, the slow gradual changes in body design are able to be seen.
A visual representation of the development of these adaptations is called a cladogram. It show points at which
various species have diverged from common ancestral forms and the endpoints of the branches represent
specific species of organisms.
1. What five probable ancestors of the modern bird (robin) are shown on the cladogram?
___________________________________________________________________________________________
2. Which dinosaur is probably the most recent common ancestor of Velociraptor and Archaeopteryx?
____________________________________________________________________________________________
3. Which traits shown on the cladogram are shared by Archaeopteryx and modern birds?
____________________________________________________________________________________________
Similar to a cladogram, the phylogenetic tree below shows a visual or graphic representation of changes over
time. In this example, we can see some of the features that separate the major groups of land plants.
4. Based upon the above diagram, what two characteristics do angiosperms and gymnosperms have in common?
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_______________________________________________________________________________________________
5. What feature do angiosperms have that gymnosperms do not? __________________________________________
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