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		Discussion: Sea urchin development can be altered by a series of environmental changes. One of these changes is temperature. In our initial experiment, we showed that sea urchins undergo cleavage more rapidly in higher temperatures. In our second experiment observations were extended over a longer period of time. We observed that changes in temperature caused changes in development. Twenty-four hours after fertilization, archenteron formation was visible in the control embryos whereas the embryos in the other two temperatures were undergoing abnormal and slow development. Lastly, 48 hours after fertilization the control embryo were all at the pluteus larvae stage while the other embryos were either dead or developing abnormally. Overall, sea urchin embryo development is temperature- dependent, with the process occurring at a faster rate and demonstrating abnormal developments at warmer than ideal temperatures, and a slower rate, and even cell death, taking place at cooler than optimal temperatures.