DragonflyIssuesInEvolution13 Wiki

Yoktwig Yoktwig 1 December 2013

Sex determination

Sex in humans confers obvious advantages of increased genetic diversity and accelerated evolution. Most Eukaryotes are not only sexual species, but they produce heterogametes. That is, male and female gametes are structurally and functionally distinct. Both sexes begin development in the same way, but the hormone testosterone redirects the male pattern during fetal development. Why is in not the other way around?

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Abeard 13 Abeard 13 30 November 2013

Phylogenetic Terms

  • 1 Phylogeny
  • 2 Monophyletic
  • 3 Paraphyletic
  • 4 Polyphyletic
  • 5 Sources

There are many terms that serve to describe the taxonomic origins of different phylogenetic groups. Phylogeny is the study of descent among species - there are many methods of classifying species into phylogenetic trees that are often in opposition (Huelsenbeck, Ronquist, Nielsen, & Bollback, 2001).  See video for a comprehensive understanding of phylogenetics.

The terms used to describe phylogenetic groups help us understand how closely related, based on current phylogenetic evidence, the group is and how common their ancestry is. Three such terms are described below:

A monophyletic taxon is one where all members of the taxon are derived from a common ancestor without exclusion.


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Kduffey Kduffey 24 November 2013

Foxy "Pleiotropy"

  I'm always on the look out for a variety of science or wildlife related books to add to my growing library. They can become especially useful if they can help support class discussions. ;) Earlier this semester I came across a copy of Richard Dawkins' " The Greatest Show on Earth" which happened to be on sale. I highly recommend it to anyone who wants to learn more about the topics covered in this course, along with learning things we may have missed out on. Dawkins basically has a conversation with you while incorporating his witty humor to break up the otherwise dry (but interesting) science facts, so theres a great flow and you don't even realize you're learning.

  In chapter 3, I came across a term I've never heard before, "pleiotropy…

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Dcoulter Dcoulter 22 November 2013

Species and Sub-species.....So what's the difference?

One of the topics we (the Speciation discussion team, that is!)  bandied about earlier this term was what makes a subspecies different than a species?  While we did not include this topic in our discussions it is something that I still (personally, anyway) find interesting. I've included an article by  Phillimore and Owens (2006) titled "Are subspecies useful in evolutionary and conservation biology?" ( http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1560251/  ) as a starting point:

"The taxonomic rank of subspecies remains highly contentious, largely because traditional subspecies boundaries have sometimes been contradicted by molecular phylogenetic data. The most complete meta-analysis to date, for instance, found that only 3% of traditional a…

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Jeffamato Jeffamato 21 November 2013

Human evolution driven by food and environment

There are  several major events in hominid evolution including: increased meat eating, cooking of food, controlled use of fire, milking of cattle, among others (Arjamaa & Vuorisalo, 2010). Events like these caused evolutionary changes in hominids from a gene-culture perspective.

Increased eating of meats helped to provide more fatty acids, which would help hominid brain evolution. Today many people take fatty acid supplements (such as fish oil pills) to help stay healthy, such as providing benefits to the cardiovascular system (Stokel, 2011).

I wonder if the lack of these fatty acids has the opposite effect on brain development in people today. Are we de-evolving? If our ancestors needed fatty acids, carbohydrates (fresh vegetables), etc. and…

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Acwfox Acwfox 18 November 2013

Plastics & Evolution

Finishing my project for Issues in Evolution, I realized how much of a love-hate relationship I have with plastic.  Plastic is everywhere & pretty much unavoidable yet it is so disruptive to the environment.

The 5 gyres & the Pacific Garbage Dump are disgusting but, from the research of my project, plastic pollution allows for colonizer species like barnacles & mollusks to latch on & relocate. 

This can become a very serious issue in regards to biodiversity & damage to ecosystems. 

Remember that every piece of plastic ever made still exists today & try to reduce your dependence on it - you'll be doing the environment good!

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Mamato Mamato 31 October 2013

Just a theory?

"MISCONCEPTION: Evolution is ‘just' a theory.

CORRECTION: This misconception stems from a mix-up between casual and scientific use of the word theory. In everyday language, theory is often used to mean a hunch with little evidential support. Scientific theories, on the other hand, are broad explanations for a wide range of phenomena. In order to be accepted by the scientific community, a theory must be strongly supported by many different lines of evidence. Evolution is a well-supported and broadly accepted scientific theory; it is not ‘just' a hunch."

This misconception was quoted from [http://evolution.berkeley.edu/evolibrary/misconceptions_teacherfaq.php#e2].  

I find it interesting how many of my students think of theories in this same li…

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