The two features are four limbs and lungs. These features were essential for animals to move from aquatic to land.
Lobe-fins are not common among the living fish and are only exhibited by the lungfish and coelacanth. However, the lobe limbs are exhibited by various living species, like humans. This is due to the fact that all the tetrapods, that is, four-limbed vertebrates, share a more recent common ancestor with the lungfish and coelacanth.
Tetrapods evolved from a group of species, which were aquatic and exhibited scales and fleshy fins. However, they also had lungs, which they used to breathe oxygen. About 360 to 390 million years ago, the predecessors of these species started to thrive in shallower waters and finally moved to land.
With this, they experienced natural selection, which assisted various adaptations for a terrestrial way of life. The modern humans still persist the proof of the aquatic past in the manner the arms and legs are attached to the body.
