. Fish use to breathe underwater. (However, many species of lobe-finned fishes that evolved during the Devonian period also had .) 6. In fossils, what anatomical evidence indicates that gills were present? 7. Many transitional species had gills which means that they lived in . 8. Lungs allow an animal to breathe . Why did this adaptation evolve? 9. Tetrapods use to breathe. Do any modern tetrapods have gills? Explain.