Convergent
evolution: New fins evolve repeatedly in teleost fishes
The adipose fin, a small appendage which
is situated between the dorsal fin and tail, was originally believed to be
useless and vestigial. However, a new study analyzing its origins finds that
these fins, which exist on more than 6,000 types of fish, arose repeatedly and
independently in multiple species. Scientists at the University of Chicago conducted
research using convergent evolution and a new model for analyzing the evolution
of vertebrate limbs and appendages. They
used ancestral-state reconstruction and developed an evolutionary tree showing
the relationships between those fish who have an adipose fin and those who do
not have one. Their data pool included over 200 ray-finned fish and fossil data
from different points in time. By revealing repeatedly that the adipose fin
evolved independently, the scientists showed that this structure might be
valuable to some fishes. This shows that different routes to building new
appendages exist and that they are not always predictable and repeatable. This
research questions prior conclusions on how new fins and limbs evolve.
I think that this article is
important to the real world. On the simplest level, this article is important
to the world today because it adds to our understanding of evolution, which is
central to the understanding of biology. If we do not understand one, we cannot
fully understand the other. As Theodosius Dobzhansky said, "nothing in
biology makes sense except in the light of evolution." More specifically,
it questions past assumptions that the adipose fin is useless. Understanding
how limbs evolved over time enables us to analyze their importance and the evolution
of their functionality. In addition, the methods that Coates and Stewart used
in their experiment could be used by other scientists to study other
structures. Lastly, the fact that something that has been so widely accepted
was successfully challenged could influence other scientists to challenge other
claims that are also currently common knowledge.
The article does a good job of
explaining how Coates and Stewart studied the evolutionary origins of adipose
fins in a way that the average person can understand. Also, the article explains
the importance and significance of the research and potential conclusions. For
example, the author wrote, "these results challenge what was generally
thought for how new fins and limbs evolve, and shed new light on ways to
explore the full range of vertebrate limb and fin diversity.” Likewise, I like
how the author included several quotes from the scientists, Michael Coates, PhD,
chair of the Committee on Evolutionary Biology at the University of Chicago,
and Thomas Stewart, graduate student in organismal biology and anatomy at the
University of Chicago, who performed the study. However, there are some areas
that the author of the article could have improved on. For example, the author
does make some assertive statements without explaining why. He states that,
“It’s exciting because it opens up new questions.” However he does not explain
how this new development may assist scientists in the future? It leaves the reader hanging about how this valuable
information could help us in the future. Also, the author includes very little
specific quantitative data. How many times did the adipose fins originate in
catfish and other groups of ray-finned fish? What was this data compared to? Likewise, the author wrote that the scientists
used a new “technique known as ancestral-state reconstruction” to study the evolutionary
origins of this fin. However, the author never completely explains this
technique. For the sake of clarity, the author should have given a detailed
explanation of this technique. Overall, however, I really enjoyed reading the
article and learned so much about this new discovery.
Citation: University of Chicago Medical Center.
"Convergent evolution: New fins evolve repeatedly in teleost fishes."
ScienceDaily. ScienceDaily, 5 March 2014.
<www.sciencedaily.com/releases/2014/03/140305084406.htm>.
Link: http://www.sciencedaily.com/releases/2014/03/140305084406.htm
I read Chrissy’s review of the article “Convergent Evolution: New Fins Evolve Repeatedly in Teleost Fishes.” She did a great job of summarizing and analyzing this article. The first thing that I really liked about her review was that it fits in so well with the evolution unit that we’ve been studying for the past two weeks. Convergent evolution was even on our test this week, so this article was interesting and relevant to me. I also liked that Chrissy used great quotes and statistics to help make her point. The data in the first paragraph enhanced the summary portion of the review, and the quotes in the second and third paragraphs were interesting and well-chosen. Another thing Chrissy did a great job with was the analysis of the positives and negatives of the article. She was very thorough in this analysis.
ReplyDeleteThere are only a couple of ways that Chrissy could have made this review even better. Overall, it was a very thorough, detailed review, but I thought that it got a little bit to long. There were certain sections that could’ve been a little less wordy or a little less detailed for the sake of keeping the review to a manageable length. I would have also liked to know some more about what ancestral-state reconstruction is and how it can be used to develop evolutionary trees for scientists to study.
I was impressed by how scientists used a combination of fossil evidence and technology to gather enough information to put together the tree in the first place, and then to make the findings discussed in the article. It’s cool that they could learn so much about convergent evolution and the evolution of fins and limbs.