The earliest terrestrial vertebrate fossils are from the late period.

Devonian period

Explanation:

The earliest terrestrial vertebrates evolved during the late Devonian period. It was the stem tetra pod that evolved from the fish and came out of water for the first time during this period. It is believed that the amphibians formed along the lineage of stem tetra pod. Due to the geographical changes during the Devonian period, the marine animals, reefs, and corals died thereby paving way for terrestrial animals.

a community that experiences major changes undergoes progress