The evolution of the jaw is one of the most significant innovations in vertebrate history. But over evolutionary time, the pill bug’s gills have adapted to life on dry land. When gills became the site of gas exchange, replacing the skin, the heart was left upstream (efferent) the gas-exchanger. Thus, oxygen-poor blood returning to the heart from the muscle and other organs is not enriched. Well, first off, there’s no advantage that would then lead to more babies… which is pretty much job one for evolution. The second pair of gill arches also became modified and evolved into support structures for the jaw. These fish may be limited in their aerobic performance a potential selective pressure for the evolution of a coronary circulation. This image shows how the hyomandibula receded in fish to … Jawed vertebrates arose from non-jawed vertebrates that had a pharyngeal gill apparatus composed of gill bars and slits. In bony fish, the gills lie in a branchial chamber covered by a bony operculum (branchia is an Ancient Greek word for gills). Like many successful features found in nature, Metaspriggina’s pairs of gill arches did not necessarily evolve for the purpose of eating or chewing.Some scientists … Contrary to popular belief, fish did not evolve gills to obtain more oxygen as they grew larger and became more active – the adaptation arose to allow them to survive acidic ocean conditions. Or did fish gills evolve at all? By Bjorn Carey 19 January 2006. Human Ears Evolved from Ancient Fish Gills. These branchial rays articulate with the gill arch cartilages in a way that is broadly reminiscent of the articulation between pectoral fins or limbs and the shoulder girdle, and this similarity led the comparative anatomist Carl Gegenbaur to propose that paired fins and limbs evolved by transformation of a gill arch (Gegenbaur, 1878) (Fig. The great majority of bony fish species have five pairs of gills, although a few have lost some over the course of evolution. Whales and dolphins did not evolve gills because they are mammals. A team reports in the journal Proceedings B that fish gills may not have evolved to help fish breathe—the standard belief among evolutionary biologists. Rather, the team concluded that fish gills evolved as a chemical-regulation mechanism. Shares. Question 7 This article answers the following question: What scientific forgery is the myth that “human embryos have gills” based on? 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