Thursday, February 2, 2012

Animal Phyla: An Introduction

Image is from Wikimedia Commons under a Creative Commons license
Ashley over at Swamp Dog Blog has inspired me to give you readers a rundown of the animal phyla, and I mean all of the animal phyla. Or at least as complete and up-to-date as I can make it.

To begin, I would like to share a bit of a disappointment I have with America's education system. When you are taught science, and biology in particular you are under the assumption that what you are learning is all that there is. No more, no less. Even though the scientific method is taught as part of this, there is no real reference to change. The facts are the facts and you better learn them because otherwise you'll not know anything about biology. As such, for a student such as my younger self, the first time I heard of anything different from that perceived set of facts it was a bit startling. Now, perhaps that was a fault of the particular teachers I had, but the wonder that there is still so much not known about the world is part of the beauty of science. Yes, there are certain things that have been tested and tested and still hold true, but other aspects of science can be anything but concrete.

One example of this uncertainty that still remains in Biology is the classification system, or rather what organism goes in which grouping. Thanks to continued discovery of new species and new knowledge of the organism through DNA testing, things have become a bit of a mess. Not only do scientists disagree as to which classification system is better, but there is work toward completely overhauling some aspects. This includes the proposed complete restructuring of Eukaryotes that would replace the traditional Animal, Plant, Fungi, and Protist with anywhere from five to eight groupings. The restructuring makes since if you know anything about "protists," since the heading really has no meaning other then "stuff that can't be easily placed anywhere else." It's likely that this will filter down to high school level texts rather soon. When I was finishing my undergraduate studies, I tutored for a while and noticed that the basic biology texts already had this system included. Also, if you're curious, the proposed system would place animals under the heading "Opisthokont" along with Fungi and certain protistants. One nice thing about this proposed reorganization is that it wouldn't affect much if any of the lower order groupings such as phyla.

Anyway, back to animal phyla. One common misconception that students currently have about the animal world is that classification is simple and narrow. This is encouraged through the teaching of a simplified version of the classification. In fact, I was rather amused to come across a page that listed only nine animal phyla. Oh boy are there a lot more than nine! In fact, the text we used when I took Invertebrate Zoology listed the following phyla:
  • Porifera
  • Placozoa
  • Cnidaria
  • Ctenophora
  • Platyhelminthes
  • Mesozoa
  • Rotifera
  • Acanthocephala
  • Gnathostomulida
  • Micrognathozoa
  • Nemertea
  • Mollusca
  • Annelida
  • Arthropoda
  • Tardigrada
  • Onychophora
  • Nematoda
  • Nematomorpha
  • Priapulida
  • Kinorhyncha
  • Loricifera
  • Gastrotricha
  • Chaetognatha
  • Cycliophora
  • Phoronida
  • Brachiopoda
  • Bryozoa
  • Entoprocta
  • Echinodermata
  • Hemichordata
  • Xenoturbellida
  • Chordata
Of course, the text only talks about the non-vertebrate chordates, but vertebrates are such a comparatively small group that the book basically covers everything. So, that is where I will begin. I will present what is listed above, altering it as needed to express any new information that I find. There's some really weird stuff, so I hope you will enjoy reading about it!


  1. Ooooh Invertebrate Zoology. Hands down the hardest course in my program when I was in school. It was tradition for the entire class to get t-shirts that said "I survived Invert Zoology" on them when we were done both semesters of it!

  2. Oh, wow! Sounds like Botany at where I went to school. That professor was the only one who actually made me cry while studying for an exam thanks to his apparent hatred of his students, absurd expectations and ineffective teaching style. He basically wanted you to memorize the entire book and spent a month talking about algae, then crammed in the entirety of plants and fungi into the rest of the semester. The text he based everything off of was written in the '80s, which didn't help at all. I amazingly managed to not fail the first time through. The course had like a 70% drop/fail rate.

    When I took invert zoo, half of the class was going crazy and constantly complaining about how hard it was. I had taken the professor before, though, and most of it was review from back when I took basic bio with her and zoology with another great professor. It was more fun than anything to me, but I did work for my A!

  3. Thanks for allowing me to brush up on my invert days, I went to school with Ashley and have the shirt. It was mighty hard but we survived. Your posts are allowing me to remember all I learned so I guess I did learn a lot through all the pain and studying.

    1. I'm glad you're enjoying them. Part of the reason I started this blog was to keep my knowledge up. It's quite fun! :)