Around 380 to 375 Ma, the primary tetrapods evolved from fish. Fins developed to turn out to be limbs that the primary tetrapods used to lift their heads out of the water to breathe air. This would let them reside in oxygen-poor water, or pursue small prey in shallow water. Eventually, some of them grew to become so well adapted to terrestrial life that they spent their adult lives on land, although they hatched within the water and returned to lay their eggs.
In natural science, hypotheses should be verified scientifically to be thought to be scientific theory. Validity, accuracy, and social mechanisms ensuring quality control, corresponding to peer evaluate and repeatability of findings, are amongst the factors and methods used for this objective. Timeline of crucial occasions in the evolution of the Earth. Gradstein, F.M.; Ogg, James George; Smith, Alan Gilbert, eds. At the end of the Ordovician interval, … Read MoreRead More »