Changes

==Fish==

==Fish==

Fish live in a relatively dense and viscous fluid, which has little oxygen carrying capacity. In order to gain sufficient gaseous exchange for survival, fish have developed a highly efficient system which has a large surface area, and utilises energy - the gills.

Fish live in a relatively dense and viscous fluid, which has little oxygen carrying capacity. In order to gain sufficient [[Gas Exchange - Anatomy & Physiology|gaseous exchange]] for survival, fish have developed a highly efficient system which has a large surface area, and utilises energy - the gills.

===Gills===

===Gills===

Gills are in the walls of both sides of the pharynx and are composed of filaments which increase the surface area.

Gills are in the walls of both sides of the [[Pharynx - Anatomy & Physiology|pharynx]] and are composed of filaments which increase the surface area.

When a fish breaths, it takes in water into the mouth, which is then forced out through the gills.

When a fish breaths, it takes in water into the mouth, which is then forced out through the gills.

'''Aquatic''' amphibians may also have ''internal gills'' and '''Pharyngeal Slits'''.

'''Aquatic''' amphibians may also have ''internal gills'' and '''Pharyngeal Slits'''.

Most Amphibia also have lungs for breathing. This contains interconnecting septa which divide the lumen into '''Faveoli''', compartments which open into a central chamber within each lung.

Most Amphibia also have lungs for breathing. This contains interconnecting septa which divide the lumen into '''Faveoli''', compartments which open into a central chamber within each [[Lungs - Anatomy & Physiology|lung]].

==Reptiles==

==Reptiles==