BIO 2135 Lecture Notes - Lecture 12: Airgas, Dermal Bone, Osmoregulation
28 Sep 2016
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Document Summary
Placodes, tripartite brain and cranium: brain locked inside the cranium, tripartite: three parts to the brain. There are vertebrae remnants, which means that they are the remains of vertebrae. Hagfish = unusual group in terms of how they function and how they live. Hagfish are able to knot which is an important function defense and feeding mechanism. For maximum flexibility, vertebrae diminish = becoming remnants (ex. Hagfish and lampreys, the closest relatives to them, are in a group called cyclostomata: cyclostomata = animals with circular mouth; jawless fishes. Unique sensory structure in fish designed to pick up vibration that is moving through water. Not really a unifying characteristic b/c it is missing in some of the lower vertebrates (ex. Water pressure or vibration moving through water is transmitted into the canal system, which has little sensory domes where it is compressed turning into nerve impulse signal integrated fish gets information about the surroundings.
