Changes

*Chelonians have adapted a '''dive reflex''' which enables them to respire anaerobically. They have extremely high levels of bicarbonate in their blood which allows them to buffer the lactic acid produced.

*Chelonians have adapted a '''dive reflex''' which enables them to respire anaerobically. They have extremely high levels of bicarbonate in their blood which allows them to buffer the lactic acid produced.

*Chelonians have an extremely short trachea in relation to their size.

*Chelonians have an extremely short trachea in relation to their size.

*Have paired lungs in the '''Dorsal Cavity'''. Intestines etc lie in the '''Ventral Cavity'''. These are separated by a diaphragmatic septum which has no muscular part.

*Chelonians have paired lungs in the '''Dorsal Cavity'''. Intestines etc lie in the '''Ventral Cavity'''. These are separated by a diaphragmatic septum which has no muscular part.

*Lungs are ventilated by leg movement in terrestrial animals, and have highly developed trunk muscles to facilitate this. Aquatic species are able to respire due to the hydrostatic pressure of water, which forces air in and out of the lungs.

*Possess large spongy lungs which reduced 80% in size when the head and limbs are retracted inside the shell.The lungs have a single intrapulmonary bronchus which radiates in a network of bronchioles and faveoli.

*Lungs are ventilated by leg movement in terrestrial animals, and have highly developed trunk muscles to facilitate this. Aquatic species are able to respire due to the hydrostatic pressure of water, which forces air in and out of the lungs. In addition, some soft shelled chelonians are able to absorb oxygen trhough their shells and skin when submerged.