Original Proposal

On the Particular Uses of Particular Lizard Limbs

Purpose

            For my final sixty days as a senior at BASIS Scottsdale, I will be conducting a research project at Dr. Rebecca Fisher’s lab at Arizona State University. I will be attempting to determine the specific functions of different types of lizard limbs — hind legs, fore legs, and tails. Explicitly, I will be studying the limb anatomy of Iguana iguanas in comparison with several different species of Anolis to link their different forms to the different habitat niches they fill and the reasons behind these adaptations. I will also be examining the regeneration of limbs as another aspect of form and function — why tails regenerate and limbs do not? Why autonomy occurs only in tails and not limbs? What anatomical differences are there between tails and limbs that may cause this?

Background

            Originally, I intended to do a project examining in depth the regeneration of lizard tails and how this process could be adapted to humans as a therapeutic treatment. However, this is not a project designed for 12 weeks. I think the idea of adaptation and the specific forms of animals relating directly to their needs is fascinating. I have always enjoyed dissection — I’ve done several in anatomy this year, I spent two weeks last year helping 8th graders dissect invertebrates, and I also frequently dissected in the 4 years I was in biology. I enjoy reading biological articles on any advances, and lately, it seems that more and more people believe that the medical field will soon have a breakthrough allowing for humans to heal themselves, through gene therapy and other less invasive methods. I subscribe to this belief quite strongly, and would like to be a part of the breakthrough, as well as further understanding the enormous amount of work that goes into even the smallest advance.

Significance

            This may seem like an esoteric project with few applications, but I would have to disagree. Anoles, and specifically Panamanian anoles, demonstrate a very clear evolutionary pattern, similar to the pattern of Darwinian finches. The numerous species have adapted to many different niches, from the canopy layer of the rainforest to the grass lands beyond the trees, and the study of these adaptations can create a model for evolutionary patterns, diversification, and ecomorphs. Also, anoles are one of the few lizards species whose entire genome has been sequenced, which means that their changes and abilities can be linked directly to genes and then a search can begin to identify analogous genes in humans. This is obviously most significant when in the form of regeneration. If the genes that enable regeneration are identified and replicated in humans, it creates an entirely new field of medicine that does not require invasive surgeries, harmful medications, or an extended recovery period.

Description

            I will be filling my sixty days with significant amounts of research, both hands on and secondary. I intend to research the anatomy of the lizards I will be looking at, as well as the current research being done on them, through primary literature in science magazines and libraries. I also plan to dissect numerous samples, and compare them to each other.

Methodology

            My project will begin in January when I take a lab and fire safety class at Arizona State University to prepare me for working in a lab that is significantly more advanced than BASIS’s. I will be working with Dr. Rebecca Fisher at a joint Arizona State University/ University of Arizona medical lab where they specifically study the functional anatomy of vertebrates. The third week of February will commence my study of lizard anatomy and physiology, extending throughout the project. At the start of March, I will begin dissecting my Iguana iguanas, as they are a larger species and better to begin examination with. I will be dissecting two iguana iguana for a larger sample size for comparison. I will be using traditional dissection tools – scalpel, needle, pick, tweezers, forceps, hemostats, scissors, mall probe, and bone cutters. Throughout April, I will dissect three different species of Anolis and begin comparing them to the iguanas as well as to each other. The weeks of May will be spent preparing my final project, presenting it to those I will be working with and finally to my peers, teachers, and parents.

Problems

            My biggest problem will be my sample size; it will be very small. This means that it will require supplementation from other data to draw any sort of conclusion. I will be using Dr. Fisher and her colleagues extensive research database on the diversification of the Anolis lizard to draw a substantial conclusion. However, given the amount of time that I have – approximately 12 weeks – I will not be able to fully answer my research question. This paired with my small sample size will mean that by the end of my project I will be able to make a good estimation of the different functional adaptations of the different species, but not any definite conclusions.

Bibliography

1. Beuttell, Kevin and Jonathan B. Losos. “Morphology of Caribbean Anoles.” Herpetological                 Monographs. 13.1. (1999): 1-28. Print.

2. Herrel, Anthony, Bieke Vanhooydonck, Joanne Porck, and Duncan J. Irschick. “Anatomical              Basis of Differences in Locomotor Behavior in Anolis Lizards: A Comparison Between Two Ecomorphs.” Bulletin Museum of Comparative Zoology. 159.4. (2008): 213-238. Print.

3. Irschick, Duncan J., Laurie J. Vitt, Peter A. Zani, Jonathan B. Losos. “A Comparison of   Evolutionary Radiations in Mainland and Caribbean Anolis Lizards.” Promoting the Science of Ecology. 78.7. (1997): 2191-2203. Print.

4. Losos, Jonathan B., et al. “Contingency and Determinism in Replicated Adaptive Radiations of    Island Lizards.” Science. 279. (1998): 2115-2118. Print.

5. Losos, Jonathan B., “The Evolution of Convergent Structure in Caribbean Anolis Communities.” Systematic Biology. 41.4. (1992): 403-420. Print.

6. Oldham, Jonathan Clark and Hobart Muir Smith. Laboratory Anatomy of the Iguana. Dubuque: WC Brown, 1975. Print.

7. Sanders, Laura. "Tails Grow Back With Dash Of Salt." Science News 178.9 (2010): 15. MasterFILE Premier. Web. 22 Nov. 2011.