![]() ![]() However, hagfish are no longer thought to be more primitive than lampreys. Lampreys are thought to have two semicircular canals, while hagfish only have one. In order to understand the evolutionary changes that led three canals, the team looked at the only two types of jawless vertebrates that still exist on earth: lampreys and hagfish. The fossil record shows that a group of jawless fish from the Paleozoic era only had two semicircular canals. ![]() Jawed vertebrates like humans have inner ears with three semicircular canals, which are what allow us to sense our position and stay balanced in the world, and especially to sense 3-D acceleration. The story begins with a difference between jawed and jawless vertebrates. ![]() This underlying philosophy helped guide the collaborative effort to study the inner ear led by Shigeru Kuratani at RIKEN BDR. Comparing organs among related animals can be helpful when trying to understand the evolutionary process, and will ultimately help us better understand organogenesis - the process through which organs develop. ![]()
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