BIO354H5 Lecture Notes - Lecture 8: Aquatic Feeding Mechanisms, Tetrapod, Quadrate Bone
Document Summary
Significant finds related to fish which leads to tetrapods - region of north western world, canada and scotland area - indicate fish tetrapod transition to have occured (no other place has the proof) Reason is because of climate change - changes to oxygen concentration is a huge factor. Need to develop jaws - change vacuum capacity and allow to absorb more oxygen and feed at the same time. Main trend is changes in oxygen concentration - jaw formation. Fish with formed jaws living in environment that is swampy - because these environments becoming more common, it meant that dissolved oxygen was low - fish didn"t have enough air in water so they gulped air. Gulping of air eventually became lungs to absorb the oxygen - highly vascularized surfaces to exchange nutrients and enhance the ability to exchange gasses - good source for gas exchange. Selective pressures act on advantage and specialize structures - making them into fully functioning lungs.
