Physiological Adaptation Examples

Simple plant and animal physiology

When we look at fish swimming in the aquarium all we see are the shape and colours. There is more to fish than those basics. To understand what goes on beneath the visible you need to be aware of some of the physiology of fish, as they are essentially all constructed the same way. Like human beings, they are all put together in the same way but with regional differences in their size, colour and shapes.

The basic arrangement of the fins of fish is common to all. There are generally seven fins on a fish body, but depending on species, there may be five or eight fins. There is the dorsal fin, found along the top of the body, an adipose fin that is generally small, set between the dorsal fin, and the tail or caudal fin. The adipose fin is not present in all species. On the lower part of the fish body what we would consider the chest area is found the pectoral fins of which there are two (Humans have pectoral muscles if you were wondering where you have heard the term). The two pelvic fins and the anal fin follow this.

Like all creatures, fish have evolved into distinct species, in the case of the guppy and other livebearers its anal fin has evolved into a gonopodium. The pectorals have evolved into wings on the "flying fish" for example. Understandably, the fins are essential to the swimming habits of the fish. The dorsal and anal fins help maintain the fish's equilibrium or upright position in the water. The tail (caudal) is used to propel the fish through the water, while the paired fins act as brakes or rudders for sudden and swift changes in direction while swimming. These are the basic uses of the fins. Individual fish species may differ, like those of catfish or rainbow fish.