He notes that air-breathing fishes were probably present during the late Silurian period (438 to 408 mya), long before the evolution of the first amphibian tetrapods in the Middle Devonian (400 to 370 mya).
Similarly, the ancestral valine residue at site −13 in SP3 was completely conserved over at least 360 million years of evolution along the amphibian lineage (Hedges et al. 2006).
Documentation of the slowly changing flow through time, as envisaged by Darwin, emerges clearly from Romer's studies of the evolution of extinct fishes, amphibians, and reptiles.
Vertebrate animals made the transition to land via the evolution of amphibians from air-breathing crossopterygian fish during Devonian times.
Based on our analyses, we conclude that the evolution of the Otop family in hominoids, amphibians, and rodents significantly departs from that of most vertebrate genomes, as does the evolution of Ush1g in the teleostei fish lineages.
Pupils will start with simple concepts of change, adaptation and natural selection illustrated by the evolution of fish to amphibians to mammals, for example.
In contrast, the additional ADAM10- and ADAM28-like metalloproteinases, which presumably arose as results of gene duplication, may have conferred selective advantages during the evolution of amphibians.
As the basal lineage of amphibians and land vertebrate, this characteristic of the caecilian genome is valuable in the study concerning the genome biology and evolution of amphibians and early tetrapods.
This pattern of mixed loci number can be explained by the occurrence of gene duplication/loss during the evolution of amphibian MHC class I genes, that is, the birth-and-death model of evolution [ 35].
However, relatively few studies have focused on the evolution of amphibian MHC class I genes, and those few studies have involved a limited number of amphibian species, mainly Ambystoma mexicanum in the Caudata [ 36] and two closely related Pipidae species (Xenopus lavies and X. (Silurana) tropicalis) in the Anura [ 37- 39].
