Phylum Chordatic Research

1. The Phylum Chordata consists of chordates that are defined by the four fundamental characteristics that they possess such as the pharyngeal gill slits, muscular post-anal tail, dorsal, hollow nerve tube and the notochord (Department of Biology 2008). However, the adult humans lack two of these significant characteristics, which are the post-anal tail and the notochord. Furthermore, humans are classified as chordates due to the similarities within characteristics. For example, humans posses the four hallmark characteristics of chordates yet, only during the rudimentary stage (Reece et al. 2013). As the development of humans continues the notochord is diminished, as it becomes part of the vertebral column while, the post-anal tail curtails

The functional importance of organs can be determined by the assumption of organ capacity (Development of Biology 2008). For example, considering the anatomy of a dogfish shark, the liver and gills prove to be the most critical organs as the liver is visibly the largest organ present with its extended growth throughout the abdominal cavity (Department of Biology 2008). Furthermore, the liver is trisected into three lobes: the right, left and the medial lobes. The liver serves to be an essential organ within the dogfish shark anatomy as it allows the shark to store oil, which allows the organism to gain buoyancy due to its heavy frame in comparison to the water (Reece et al. 2008). Moreover, the gills serve to be another significant organ for the shark as they enable oxygen and gas exchange within the natural environment (Reece et al. 2013). However, inaccuracies are present within the assumption that organ capacity dictates the functional importance as the organism’s body plan is a derivation from natural selection which has allowed many animals to persist over the course of evolutionary changes (Reece et al. 2013). In addition, physical laws that drive movement, heat exchange, diffusion, etc. prove to be indispensable for the structural development of organisms (Reece et al. 2013). For example, the heart, which is relatively small in size yet its purpose is highly significant as the heart is the driving force for circulation and the movement of aqueous fluids within an