AP Biology Jason Cushman
Current Event 12 2/22/16
A Parasite, Leopards,
and a Primate’s Fear and Survival
Members
of the scientific community have been recently looking into the many bite marks
on the bones of a large portion of ancient hominins which are caused by large
African Felines and leopards. Through
their investigations and studies of chimpanzees in the Ivory Coast, many have
concluded that these cats were and still are one of the biggest and most
dangerous predators to our ancestors and the Hominina Clade. Of the chimpanzees studied, scientists
estimate that on average, they have a 30 percent chance of being attacked by a
leopard each year. Through this
research, a study has been published proving that the leopards have had a lot
of help from a single-celled parasite known as Toxoplasma Gondii. This parasite messes with the fear-related
regions of the brain and removes the natural defense mechanism in chimps that
makes them afraid of cats. Toxoplasma
Gondii was first studied in the 90s in rats where scientists saw similar results
in their fear of house cats. Scientists
concluded that those infected lost their fear of cat odors and some claim that
they were even attracted to those odors.
The parasite’s evolution to have this effect on animals is due to the
parasite’s life cycle. When ingested by
a cat, Toxoplasma Gondii travels to the gut where it can reproduce and create
oocysts that are expelled in feces and can survive for months until it is
picked up in a new animal. Therefore, it
evolved to make it easier to reach the gut of the cat by making its original
host easy prey. A new study has found
that this parasite is also in and affects birds and other mammals including
humans. 11 percent of Americans have it
and in some extreme cases, countries have been observed to have 90 percent of
their population infected. Though
generally the parasite is dormant in cysts in the brain due to healthy immune
system suppression, recent studies have found some symptoms linked to this
disease. Women have been observed with
heightened aggression and men, increased impulsiveness. The parasite has also been known to cause
more serious health complications in fetuses and those with compromised immune
systems.
This is
fairly worrying because of its prevalence in not only mammals but humans as
well. The fact that a vast majority of
some countries are infected is dangerous and could lead to many problems in
those country’s’ futures. Although
leopard attacks are not a major risk for most humans, some of the reproduction
health complications that Toxoplasma Gondii can create along with the possibility
for further, potentially dangerous mutations.
Furthermore this information could be used to more accurately hypothesize
the development and migrations of the Hominina Clade. Scientists may be able to use maps of high
cat density and understand what our ancestors did to avoid them. This discovery could also aid neuroscientists
in examinations of the fear center of the human brain and how it can be
manipulated. This could have many
practical uses such as helping people with diseases like PTSD.
This
article was very well written and very informative. Zimmer used many different studies to give a
very complete picture of what is happening and gave detailed descriptions of
each study along with the scientists who completed them. He did an especially good job of summarizing
all of the information and linking it together very smoothly. He also made sure that it was very
understandable for the reader by including many definitions and
explanations. I really enjoyed the way
he wrote the article in a chronological fashion, explaining the views of
scientists based on one study and how
that changed with each progressing study.
My primary criticism of this article would be that there is a lack of
discussion of possible future implications this parasite could create for
humans and other animals. Without this
part, the article lacked a clear relevance and left the reader to guess what it
may be. Otherwise this article was
practically flawless and a very good read.
Zimmer, Carl. "A Parasite, Leopards, and a Primate’s
Fear and Survival." The New York Times. The New York Times, 15 Feb.
2016. Web. 22 Feb. 2016.
I loved your review for a number of reasons. First, you had an intriguing hook to start off your review. By saying, “Members of the scientific community have been recently looking into the many bite marks on the bones of a large portion of ancient hominins which are caused by large African Felines and leopards,” you really reeled the reader in, making him or her want to find out more about these ancient bite marks. Another area I thought you did really well in was keeping your review consistently clear and concise. One particular part that I thought you presented especially clearly was the part in which you presented the reason behind the leopards’ biological success. Here, you said, “Through this research, a study has been published proving that the leopards have had a lot of help from a single-celled parasite known as Toxoplasma Gondii.” This is quite clear, and it also provides a nice, concise transition into your discussion of the parasite. Finally, I loved the way you backed up the author’s argument in your review, making sure to show the can see the evidence and numbers that go into these generalizations about leopards and other large felines. For instance, in the first paragraph of your review alone, you stated, “Of the chimpanzees studied, scientists estimate that on average, they have a 30 percent chance of being attacked by a leopard each year.” This directly backs the author’s argument, making it more credible to the reader. Overall, Jason it was a great review.
ReplyDeleteWhile there were numerous things I liked about your review, like the things I mentioned earlier, you also had some room for improvement. For example, one thing I didn’t like about your review was the fact that you didn’t go into the actual reaction that occurs in the brain when the parasite is released, and this is something I would have been interested in reading about. The only thing you mentioned on this topic was, “This parasite messes with the fear-related regions of the brain.” I think you should have added some comment on what part of the brain the parasite enters and how this actually triggers the chimps’ brain as a whole to act differently. Another reason I didn’t like your review was because you failed to go into the severity of this parasite. You said, “Though generally the parasite is dormant in cysts in the brain due to healthy immune system suppression, recent studies have found some symptoms linked to this disease.” By saying hinting that our immune systems do a fine job fighting off this parasite, but it occasionally tends to show its colors, you double-cross yourself and leave the reader wondering just how serious the possibility of getting this disease is. Instead you could have provided a little more information about the strength of our immune system against this parasite, for example, which would have cleared up how likely it is that our immune system fails. These were the only two reasons I didn’t like your review; other than these, it was fantastic!
This review was truly amazing, and I learned so much by reading it. I thought this review was very informative, for it captured a complex topic like the transmittance of a fear-reducing parasite from one species to another and made it understandable for the reader. Because of this, I am now able to understand how leopards and other large felines are able to be so biologically successful and how the parasites they release can be applied to other species. The reason I chose this article review out of all the others is because of its catchy title. When I saw the title “A Parasite, Leopards, and a Primate’s Fear and Survival,” I just couldn’t resist, and I had to learn more about this mysterious, powerful parasite. This review also made me consider my own life, genome, body, brain, etc. Since Jason pointed out that this parasite is present in humans as well as leopards, I may research its effect on humans some more and possibly even consult a doctor about how worried I should be (as crazy as that sounds).
Jason, well done! I really enjoyed reading your current event report. I was drawn to the title of the article because it was very interesting. One thing that I think you did really well was giving simple background information that was able to accurately allow the reader to understand the context of the information in the article. By giving that information to start the report, it made it easier to understand the rest of the article. Also, you did a good job in giving an appropriate amount of detail about the parasite, Toxoplasma Gondii. This parasite, which affects the brains of chimps, is a complicated topic that could be misunderstood. The parasite affects the area of the brain that produces fear and makes leopards natural enemies to chimps. A third thing that I think you did a good job on was your second paragraph, the connection and importance that this topic can hold in the outside world. You did a good job explaining how the virus could possibly affect mammals across the world and talked about how scientists were working to combat it.
ReplyDeleteAlthough you did an exceptional job reporting on this article, there were a few areas that I think you could work on to make your report even stronger. The first recommendation I would make is that you incorporate direct quotes from the article and the scientists. I always feel that direct quotes make any argument stronger and can allow readers to more directly hear the opinions of scientists. The second area that I think you can improve on is giving a more in depth explanation as to why you picked this article. I always think it is interesting to read why others find an article interesting and comparing it to my own thoughts.
I chose to read your report because the article title caught my eye. I am glad that I read it because the topic was interesting and taught me things that I had not known about. Prior to reading your report, I did not know what the Toxoplasma Gondii parasite was. Now, I know about it and am aware of the danger it presents. This is change my perception of the world because I now know more things that pose a threat to our wildlife. Great job!