Difference Between Pisces and Tetrapoda

Now we will discuss what are Pisces, what are Tetrapoda, similarities between Pisces and Tetrapoda, difference between Pisces and Tetrapoda but before we start we will discuss about the position of Pisces and Tetrapoda in animals.

Presence or absence of jaw and paired appendages divide the Vertebrate in two groups, Agnatha and Gnathostomata.

Gnathostomata have jaw and paired appendages but the appendages present in all members of Gnathostomata is not similar.

In fishes the paired appendages present in the form of pelvic and pectoral fins. But in case of amphibia, birds, mammals the paired appendages are different and those dissimilarity is used to divide the Gnathostomata into two groups, Pisces and Tetrapoda.

Table of Contents

What are Pisces:

The simple meaning of word Pisces represent fish, Pisces have paired appendages in the form of fin. Fin may present in pairs or odd, pectoral and pelvic fin help them to swim fast in water.

Fish are aquatic Gnathostomes, some are freshwater while some are marine water animals.

Placodermi contain primitive fishes, they are extinct now, the true fish we see today are either Osteichthyes or Chondrichthyes.

As fishes are aquatic so they take oxygen from water and leave carbon dioxide into water through gill, their body shape is streamlined which helps them to reduce the water resistance and help to move swiftly.

Fish have different types of aquatic adaptation, their streamlined body shape, presence of gill, dermal scale as exoskeleton, osmoregulation all are required for survival in aquatic habitats.

What are Tetrapoda:

The term Tetrapoda means presence of four appendages or limbs, in Tetrapoda fin-like appendages not present, instead they have limbs.

The paired limb give more advantages over fin, the limbs are modified in different patterns in different animals for different functions.

For example the limbs in a birds are not similar to the limbs in other Tetrapoda, forelimbs are converted into wings in birds while the forelimb in mammals has different functions.

The appendages in fish, fin help in movement which in Tetrapoda the appendages perform different types of functions.

Tetrapoda are mostly terrestrial and they can walk, run along with swimming. Tetrapoda contain advanced chordates, amphibians, reptiles, birds, mammals, it is believed that Tetrapoda have evolved from Pisces.

So we can say that Pisces are ancestors of Tetrapoda, lobe-finned fish evolved into early Tetrapoda and in this way, amphibians come to land from water first time.

Similarities Between Pisces and Tetrapoda:

As Pisces and Tetrapoda belong to Gnathostomata, it is normal that both of them have much similarity, both pieces and Tetrapoda have cranium, vertebral column, jaw and appendages.

Though most of the Tetrapoda do not have fin but some Tetrapoda have fin-like appendages, obviously they do not similar in anatomical perspective.

Most of the Tetrapoda are terrestrial but some Tetrapoda are aquatic and they have aquatic adaptation like Pisces.

Pisces and some Tetrapoda have scale as exoskeleton but they are not similar in their origin.