The Yellow-Toed Skink

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Introduction
In this research paper I will be discussing the Yellow-Bellied Three-Toed Skink and how instead of this reptile laying eggs like most reptiles would do, it is giving birth to live young instead. The Yellow-Bellied Three-Toed skink (Saiphos equalis) is a small reptile in size that closely resembles that of a snake, but with four legs. This specific species of skink can be found in New South Wales, Australia. It has been discovered that in the cold regions of New South Wales this organism is producing live young. However in the warmer regions of New South Wales this same exact species is laying eggs. (Handwerk, 2010). As stated in the National Geographic News, “Evolutionary records shows that nearly a hundred reptile lineages have …show more content…

Meaning that the babies are able to stay in a warm place for an extended period of time due to the geographic region that this skink is located in. So basically what the mother is doing is protecting her young. That idea is the root of what evolution is and makes perfect sense as to why scientist are saying that this organism is currently going through an evolutionary change. With that being said it is also believed that during this process the eggshell gets reduced to a much thinner one (Packard et al., 1977). This thin egg shell is then gone by the time the babies are ready to be born, thus the appearance of live birth. The normal skink egg shell is a thicker one that made up of proteins and …show more content…

The skinks that retain the eggs (produce live birth) were taken from the Southeastern part of New South Wales, and the skinks that laid eggs were taken from the Northern part of New South Wales (Smith and Shine, 1997; Linville et al., 2010). The skinks were then placed in a care facility at the University of Sydney in groups of up to 6 females in a glass aquarium set to room temperature at 20 °C. Each aquarium was provided with food, water, and a 25-W incandescent light bulb. (Stewart, 2010). The skinks were then euthanized and an oviduct was removed from each female so the embryo could be tested. Each embryo was then stained with one of the four protocols, 1. Hematoxylin and eosin, for general structure, 2. Alcian blue, for carboxyl and sulphate-ester groups of acid, 3. Periodic acid Schiff, for neutral hexose sugars, and 4. Dihydroxy-6, 6'disulfide-dinapthyl, sulphydryl and disulfide groups (Kiernan, 1981). The

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