Science Skills Practice, AP Biology
Homework: August 28, 2014
A primary journal article is written by the investigators with conducted a scientific study. Primary
journal articles are published in peer reviewed journals; other scientists whose work is similar review the
manuscript to ensure that the investigation and its reported results reflect sound scientific inquiry. The
two most widely read primary science journals are Science and Nature.
A secondary journal article is written by someone who has read the primary journal article and who
often has often interviewed the investigators who authored the study. Most secondary journal articles
are published in either primary journals, where other scientists present a short discussion of the paper
and its importance within the field of study. Some secondary journal articles appear in lay science
journals written for nonscientists with an interest in science. If several secondary journal articles are
available, the one published in a scientific journal is usually of higher validity.
A tertiary journal article is written by someone who has read a secondary journal article, then reports
upon it; these reports can be found in news websites, on television news, or in newspapers. Sometimes
these reports are actually even further removed from the investigator’s original report, being reports of
tertiary journal articles.
Like the children’s game of “Telephone”, the farther removed from the actual investigator’s words, the
less valid and more faulty a scientific report is likely to be. Biologists must be proficient in reading
primary journal articles, even those not directly in their own field.
The references below are all reports on the topic of similarities in appearance between non-venomous
King snakes and venomous Coral snakes. The first primary journal article provided the basis for further
tests conducted by the second, and the third and fourth articles build upon these.
1. As you read the primary journal articles note the content of the different sections of each
article; the format of articles differs from journal to journal, but certain common features can be
determined. AP Biology Lab reports will be modeled after letters to Nature.
2. Compare the first and second article to determine how the scientists in the Nature article built
upon the findings of the scientists in the Science article AP Biology Lab reports will be modeled
after letters to Nature.
3. Compare the secondary and tertiary journal articles to the primary articles to note how they
differ in accuracy, depth, and focus.
file:///C:/Users/nbrown/Downloads/1981_Coral_snake_mimicry_Science.pdf
http://www.napavalley.edu/people/sburns/Documents/Biol120/2001_Nature_mimicry_snakes.pdf
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follow-up to this study by other scientists
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842773/pdf/rspb20092000.pdf
Secondary journal article written for non-scientists with an interest in science
Study Of Poisonous Snakes Boosts Old Batesian Principle Of
Mimicry
Date:
March 23, 2001
Source:
University Of North Carolina At Chapel Hill
Chapel Hill –
In 1862, British naturalist Henry Bates proposed -- but could not prove -- that over time, some animal and
plant species that taste good to predators come to resemble other animals and plants that pose a danger
to the hungry hunters.
By evolving in that way, the good-tasting species develop an effective defense mechanism and are more
likely to survive and reproduce.
Although widely accepted and taught as early as elementary school, Batesian mimicry has remained
unconfirmed. Now, however, a University of North Carolina at Chapel Hill scientist believes experiments
he and others conducted with fake snakes strongly show the Englishman was right. Their report appears
in the March 15 issue of the journal Nature. Authors are Dr. David W. Pfennig, associate professor of
biology at UNC, undergraduate William R. Horcombe and Dr. Karen S. Pfennig, postdoctoral fellow at the
University of Texas at Austin.
"What made Bates' idea so attractive and so unusual for its time was that there was no direct interaction
between the dangerous species, which we call the model, and the mimic species," Pfennig said. "Instead,
the evolution of mimicry was driven by the predators because if they didn't learn to avoid dangerous prey,
they would not survive themselves. The ones that did survive were more likely to leave behind genes
causing them to avoid danger." The question became -- if you've got two species that look like each other
-- how do you determine if it's really mimicry? he said.
"Lots of other nice studies of mimicry have been done, but we believe ours is the first to really test this
critical prediction, which is that where there's no dangerous model present, then the protection from
mimicry should break down," Pfennig said. "If the model that presents a risk is present, then there's very
strong selective pressure to avoid the mimic."
In their experiments, he, his wife Karen and his student Horcombe relied on the striking similarity between
deadly U.S. coral snakes and scarlet king snakes. Both species bear bright red, yellow and black bands,
but the chief visual difference is that in the coral snake, the red and yellow rings touch, while in the scarlet
king snake, a black band usually separates the lighter colors.
The researchers created 1,200 life-size models of coral and scarlet king snakes out of plasticine, a
mixture of wax and modeling clay and placed the copies in the wild, both within the coral snake's natural
range in the southeastern United States and north of that range in central North Carolina, where they are
absent. The biologists reasoned that if mimicry were causing the king snake to resemble the coral snake,
predators would be more likely to attack the former where coral snakes are not found.
And that's just what their experiments showed. Because the plasticine models retained bite and scratch
marks, they became a clear record of how often predators grabbed them.
"Attacks were much more frequent on our ringed models in central North Carolina than they were in
southern North Carolina and South Carolina, about 50 percent vs. about 6 percent," Pfennig said.
"Various predators readily attacked our model scarlet king snakes but only where no coral snakes lived."
The UNC team also conducted comparable experiments in Arizona with the same results, Pfennig said.
Controls were fake "snakes" bearing either stripes rather than rings or plain brown skin. "These are very
exciting results because they show how very strong natural selection is even in areas that are not so far
away from each other," the scientist said.
Bates made his original observations about mimicry's effects on natural selection on similarly appearing
butterflies, some of which were toxic to birds while others were not, he said. "You can get resemblances
between species that have nothing to do with mimicry," Pfennig said. "Sharks and dolphins look very
much alike, but those forms probably evolved millions of years ago because they were so efficient for
swimming. We call that process convergent evolution."
Story Source:
The above story is based on materials provided by University Of North Carolina At Chapel Hill. Note:
Materials may be edited for content and length.
Tertiary Resource
http://www.wildlife-removal.com/snakelookalike.html
Coral Snake Look Alikes - Mimicry
Sometimes in nature a dangerous, or venomous animal will develop a bright color pattern that tells other
animals, "stay away"! Then sometimes other animals that aren't dangerous will evolve a similar color
pattern that copies the dangerous animal - this is called Batesian Mimicry. A great example is found in
coral snakes and the types of snakes that look like coral snakes. These look alike snakes copy the color
pattern of coral snakes, the red yellow black bands around the body. However, if you look closely, you'll
see that the colors aren't exactly the same. With the coral snake, red touches yellow. With the copycats,
red touches black. Look at the below photographs, of the Scarlet Kingsnake and the Florida Scarlet
Snake. You'll also notice that the copy snakes have light bellies, and a big difference is that the coral
snake has a black nose and the lookalikes have a red snout. Learn more by reading my coral
snake page, or my snake color poem page.