DO PANDAS REALLY EXIST? – TEACHER HANDOUT
Grade Level:
•
High-school biology
Objectives:
The students will:
•
•
•
•
•
Become familiar with the current uncertainty regarding the relatedness of the raccoons,
pandas, and bears.
Understand that scientific interpretations change as new data become available.
Evaluate three proposed phylogenetic trees that show the relatedness between the
raccoons, pandas, and bears.
Use biogeographical, behavioral, morphological, and molecular data to evaluate the
possible phylogenetic reconstructions.
Outline the steps of how the “pandas thumb” (enlarged sesamoid bone) may have
evolved.
Background Information:
The students should already be familiar with the following topics:
•
•
•
Phylogenetic trees
DNA structure
The steps of acquiring adaptations (natural selection)
Time Requirement: (Includes time for a short introduction to the panda species and a followup discussion)
•
Two 70-minute blocks or three 45-minute class periods
Teacher Preparation:
•
Make copies of the 2 handouts.
Materials (one per student):
•
•
Student handout - “Do Pandas Really Exist?”
Student handout – “Background information on the question: ‘Do Pandas Really Exist?’”
Evaluation:
•
•
Answers on student handout, even if technically incorrect, should be defensible.
Check for understanding during classroom discussion.
DO PANDAS REALLY EXIST? TEACHER HANDOUT
1. What question were scientists trying to answer?
Scientists were trying to determine if pandas are more closely related to the bears or the
raccoons.
2. Below are the three possible phylogenetic trees that scientists have proposed for the
raccoons, bears, and pandas. A phylogenetic tree shows how closely different species are
related to each other. The closer two branches are to each other on the tree, the more
closely the species are related to each other. For example, all three of these trees show that
the raccoon (Procyon lotor) is very closely related to the coatimundi (Nasua nasua), which
are both members of the raccoon family (procyonidae).
a. According to these phylogenetic trees, what other two species are closely related to
each other? The grizzly bear and sun bear.
b. To which family do these two species belong? Ursidae
c. According to the background information (in “Do Pandas Really Exist?”), fill in the option
numbers for each of the phylogenetic trees.
d. According to the background information on each of the proposed relationships, fill in the
“red panda” and the “giant panda” on the phylogenetic trees.
3
Option # _____
1
Option # _____
Procyon lotor
Procyon lotor
Nasua nasua
Red panda
Nasua nasua
Procyon lotor
Nasua nasua
Red panda
Giant panda
2
Option # _____
Red panda
Giant panda
Ursus arctos
Ursus arctos
Ursus arctos
Ursus malayanus
Ursus malayanus
Ursus malayanus
Giant panda
3. Look at the biogeographical information that has been provided.
a. Which option (1, 2, or 3) does this information support? __3__
b. Explain your answer. Both pandas live near each other in Asia, but neither live
near the raccoon family.
4. Look at the fossil information that has been provided. If raccoons first appeared in North
America some 20 million years ago, and the red panda is a descendant of these original
raccoons, how could they have ended up in China? (Hint: look at the map that shows how
the continents have moved over time.) They may have lived near each other, at one time,
but the continents have moved and could have split their descendents apart.
5. Read the behavioral information that has been provided.
a. Which option (1, 2, or 3) does this information support? __3___
b. Explain your answer. Both pandas eat bamboo (bears do not do this) and both
mark their territory using scent glands (bears do not do this either).
6. Look at the information that has been provided about the size of the animals in Table 1.
a. Which option (1, 2, or 3) does this information support? __2___
b. Explain your answer. The red panda has a weight and skull length within the
range of the procyonids and the giant panda has a weight and skull length
within the range of the ursids. However, both species of panda give birth to
very small offspring.
7. Table 1 includes the dental formulas for each species. A dental formula shows how many
of each type of tooth a species has on one half of the mouth (I = incisor, C = canine, P =
premolar, and M = molar). The number in the numerator is how many they have in the upper
jaw, and the number in the denominator is how many they have in the lower jaw. The
number after the “=” is the total number of teeth the animal has. For example, the in just the
left or right side of their mouth the raccoon (Procyon lotor) has 3 incisors in the upper and 3
in the lower jaw, 1 canine in the upper and 1 in the lower jaw, 4 premolars in the upper and
4 in the lower jaw, and 2 molars in the upper and 2 in the lower jaw. If you add all of these
up and multiply by 2, you will see that the raccoon has a total of 40 teeth.
a. Which option (1, 2, or 3) is supported by the dental formulas? ___2____
b. Explain your answer. The dental formula of the giant panda is the same as those
of the bears. The red panda has a dental formula that is different than the
others, but is most similar to the procyonidae. The procyonids have two more
upper premolars than do the red pandas. Otherwise, they are identical.
8. It is very difficult for a large animal like the giant panda to get enough calories from eating
bamboo shoots. Yet, they manage to do it with the help of their “thumb” (see Figures 11
and 12). Fill in the table below to explain how the giant panda ended up with this interesting
adaptation. Be sure to use the word “sesamoid bone” in your answer.
Steps to getting adaptation
The panda’s “thumb”
1. Organisms produce more offspring
than can survive to reproduce.
Giant pandas produce more offspring than can
survive to reproduce.
2. Offspring vary, and some of the
variation is due to genetic differences.
3. Selective pressures are present.
Because of genetic differences, some giant pandas
have sesamoid bones that are longer than others.
They are faced with the selective pressure of getting
enough calories from the bamboo.
Pandas with longer sesamoid bones are better able
to strip the leaves off of the bamboo and get
calories more efficiently than the others. This makes
them more likely to survive, reproduce, and pass the
trait on to their offspring.
4. Organisms with beneficial heritable
variations are more likely to survive,
reproduce, and pass the trait on to
offspring.
9. Now let’s summarize the conclusions you have
drawn so far.
Type of
Option Option Option
evidence
1
2
3
Biogeography
√
a. Place a checkmark beneath the option # that is best
Behavior
√
supported by the evidence.
Diet
√
b. Add up the total number of checkmarks in each
Size
√
column and write them down as totals.
Dental
√
Formula
c. Based on your evidence so far, how do you think the
Total =
2
3
two panda species are related to the raccoon and
bear families? So far, it seems as thought the two pandas are most closely related to each
other.
DNA Evidence. In the 1980s and 1990s scientists compared the DNA of various raccoons,
bears, and pandas. By looking at a particular sequence of nucleotide bases (A, T, C, and G)
they were able to compare their similarities and differences across species. The idea is that the
more similar the DNA sequences are to each other, the more closely related the species are.
Also, the more different the DNA sequences between species, the more distantly related the
species are. Below is a representation of what they found:
Species
Raccoon (Procyon lotor)
Coatimundi (Nasua
nasua)
Grizzly Bear (Ursus
arctos)
Sun Bear (Ursos
malayanus)
Red Panda (Ailurus
fulgens)
Giant Panda (Ailuropoda
melanoleuca)
DNA Sequence
A T A T A
A T A T A
A
C
A
A
A
G
T
T
A
A
A
A
G
G
A
A
T
T
A
A
C
C
C
C
A
A
C
C
G
G
C
T
G
T
A
C
C
A
T
A
C
C
A
T
A
C
C
C
C
C
C
A
G
T
A
C
C
A
T
A
C
C
A
T
A
C
C
C
C
C
C
A
G
T
A
C
C
A
A
T
A
T
A
T
A
C
C
A
C
G
C
A
G
T
A
C
C
A
T
A
C
C
A
T
A
C
C
A
C
G
----
10
8
1
----
4
2
7
5
----
Giant Panda
11
9
----
Red Panda
2
----
Sun Bear
Grizzly Bear
Raccoon (Procyon lotor)
Coatimundi (Nasua nasua)
Grizzly Bear (Ursus arctos)
Sun Bear (Ursos malayanus)
Red Panda (Ailurus fulgens)
Giant Panda (Ailuropoda melanoleuca)
Coatimundi
Teachers, please note that the DNA
sequences have been fabricated. However,
they do reflect the relationships provided
by molecular data.
Raccoon
10. Look at the DNA sequences above (it is helpful if you have an extra copy that you can cut
out). Figure out how many nucleotide base differences there are between all of the
combination of different species and fill in the table below. Fill in the number of nucleotide
base differences between each pair of species.
8
6
3
2
4
----
11. DNA evidence.
a. Which option (1, 2, or 3) does the DNA evidence support? __2___
b. Explain your answer. The DNA of the red panda is most similar to the
procyonids and the DNA of the giant panda is most similar to the bears.
12. How did the DNA sequences become different from each other in the first place? Mutation
13. Like DNA, proteins can also be compared to determine relatedness.
a. Explain how you think scientists could compare proteins of different species.
Answers may vary but may include – amino acid sequences, how big the proteins are,
etc.
14. What other information would have been helpful to you in this investigation?
Answers may vary but may include – information on more bear and raccoon species,
actual fossil information, etc.
References:
ARKive: Images of life on earth. (2004). Wildscreen. Retrieved October 1, 2005 from
http://www.arkive.org
Ballenger, L. and T. Dewey. (2002). "Ursus arctos" (On-line), Animal Diversity Web. Retrieved
October 01, 2005 at
http://animaldiversity.ummz.umich.edu/site/accounts/information/Ursus_arctos.html.
Bies, L. (2002). "Helarctos malayanus" (On-line), Animal Diversity Web. Retrieved October 01,
2005 at
http://animaldiversity.ummz.umich.edu/site/accounts/information/Helarctos_malayanus.h
tml.
Braddy, S. (2003). "Nasua nasua" (On-line), Animal Diversity Web. Retrieved October 01, 2005
at http://animaldiversity.ummz.umich.edu/site/accounts/information/Nasua_nasua.html.
Cartwright, R. (2004). Whence the giant panda? De Rerum Natura (On the Nature of Things).
Retrieved October 15, 2005 from:
http://www.dererumnatura.us/archives/pdfs/2004/05/whence_the_gian.pdf
CDSP. (2003). Plate tectonics and the creation of continents. Carlsberg Ridge Cruise. The
Classroom@sea Project. Retrieved October 1, 2005 from
http://www.soc.soton.ac.uk/CHD/classroom@sea/carlsberg/index.html
Flynn, J.J., M.A. Nedbal, J.W. Dragoo, and R.L. Honeycutt. (2000). Whence the Red Panda?
Molecular Phylogenetics and Evolution, 17, 190 – 199.
Giant Panda. 2005 baldeagleinfo.com. Retrieved October 1, 2005 from
http://www.baldeagleinfo.com/zoo/panda.html
Goldman, D., P.R. Giri, and S.J. O’Brien. Molecular genetic-distance estimates among the
ursidae as indicated by one- and two-dimensional protein electrophoresis. Evolution,
43(2), 282 – 295.
Hashimoto T, Otaka E, Adachi J, Muzuta K, and Hasegawa M. (1993). The giant panda is close
to a bear, judge by α- and β-hemoglobin sequences. Journal of Molecular Evolution
36:282-289
Mayr, E. (1986) Uncertainty in science: is the giant panda a bear or a raccoon? Nature 323
pp769-771
Morris, P.J. and S.F. Morris. (January, 2000). The Panda’s Thumb. Anthro Limited. Retrieved
October1, 2005 from http://www.athro.com/evo/pthumb.html
National Park Service. (December, 2004). Cuyahoga Valley National Park. NPS.gov. Retrieved
on October 1, 2005 from http://www.nps.gov/cuva/kidstuff/alphabet/r.htm
Nature, August 15, 1991 v352 n6.336 p573(1) Riddle of the giant panda. (evolutionary patterns
with other pandas and bears) Ya-Ping Zhang; Li-Ming Shi.
Nowak, R. M. (1991). Walker’s Mammals of the World. Baltimore: The Johns Hopkins University
Press.
O’Brien SJ, Nash WG, Wildt DE, Bush ME, and Benveniste RE (1985) A molecular solution to
the riddle of the giant panda’s phylogeny. Nature 317 pp140-144
Postanowicz, R. (2004). Coatimundi (Nasua nasua). Lioncrusher.com, Retrieved October 1,
2005 from http://www.lioncrusher.com/animal.asp?animal=78
Schaller, G.B. (1993). The Last Panda. Chicago: University of Chicago Press.
Skulls Unlimited International. (December, 2005). Retrieved from http://www.skullsunlimited.com
Slattery, J.P. and S.J. O’Brien. (1995). Molecular phylogeny of the red panda (Ailurus fulgens).
Journal of Heredity. 86, 413 – 422.
Thinkquest. (1998). Giant Panda. World Endangered Species. Retrieved on October 1, 2005
from http://library.thinkquest.org
Zoological Society of San Diego. (2005). Sun bear map. SanDiegoZoo.org. Retrieved October
1, 2005 from http://www.sandiegozoo.org/animalbytes/images/sun_bear_map.jpg