Vertebrate land invasion

The vertebrate land invasion refers to the eco-evolutionary transition of vertebrate animals, more specifically of the sarcopterygian clade Tetrapodomorpha, from aquatic/semiaquatic "fishapods" to predominantly terrestrial tetrapods during the Late Devonian period. This transition allowed these vertebrates to escape competitive pressure from other aquatic animals and explore new ecological niches on land, which eventually established the vertebrates as the supreme phylum of the terrestrial food webs. Fossils from this period have allowed scientists to identify some of the species that existed during this transition, such as Tiktaalik and Acanthostega. Many of these species were also the first to develop adaptations suited to terrestrial over aquatic life, such as neck mobility, more efficient lungs, air-transmitted hearing, water-retaining integuments and physiology, and robust appendicular skeleton for limb weightbearing and terrestrial locomotion.

The late Devonian vertebrate transition was preceded by the terrestrial floral invasion of plants and fungi, with invertebrates such as arthropods following afterwards. These biotic colonization on land created vast swathes of wetland coal forests during the Late Devonian and Early Carboniferous, allowing for the development of primitive terrestrial ecosystems that would be available to accommodate habitation by amphibian vertebrates such as temnospondyls and lepospondyls, latter of which is thought to give rise to the fully terrestrial amniotes. While the Late Devonian event was the first land invasion by vertebrates, newer aquatic species have continued to develop adaptations suited to terrestrial life (and vice versa) from the Late Devonian to the Holocene. Several group of tetrapods, however, evolved secondary re-adaptation to aquatic life later on.