Essay on The Evolution Of A Fish

883 Words Nov 15th, 2016 4 Pages
Fish’s consist of a diverse amount of species each known for their characteristics that set them apart from the rest. The characteristics that make the general understanding of a fish are, vertebrate, aquatic, Gills rather than lungs, paired limbs(fins) for locomotion, and are covered with scales. When we see fishes in aquariums we have an irresistible urge to tap the glass, and in doing so, a lot of the fishes get startled and move away performing a sequence of steps called an c-start used as an escape mechanism, the name was give due to their characteristic shape. The intricacies of the c-start are important to figure out why such an escape reflex comes to action; the escape reflex is studied on the Goldfish (carassius auratis) by Mirjany et al. Fishes contain the Lateral Line that is used to detect changes in their aquatic environment such as, water motion and changes in pressure. The lateral line consists of neuromasts that are specialized in the detection of the changes in the water, thus can identify sound fields, the neuromasts are innervated by the anterior lateral line nerve (aLLn) and posterior lateral line nerve(pLLn), which are found in the head and trunk of the fish respectively. Mauthner cells (m-cells) are important in the startle response which help the fish avoid the cause of the stimulus. M-cells are a pair of reticulospinal neurons that are found in the hindbrain of fishes, the m-cells main input are hair cells, but the lateral line plays a key role in…

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