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Tetrapod. A tetrapod (/ ˈtɛtrəˌpɒd /; [5] from Ancient Greek τετρα- (tetra-) 'four' and πούς (poús) 'foot') is any four- limbed vertebrate animal of the superclass Tetrapoda (/ tɛˈtræpədə /). [6] Tetrapods include all extant and extinct amphibians and amniotes, with the latter in turn evolving into two major clades, the ...
Class Amphibia (amphibians, some ancestral to the amniotes)—now a paraphyletic group; Class Synapsida (mammals and the extinct mammal-like reptiles) Class Sauropsida (reptiles and birds) While this traditional classification is orderly, most of the groups are paraphyletic, i.e. do not contain all descendants of the class's common ancestor. [46]
Slight increase in diversity of cold-tolerant ostracods and foraminifers, along with major extinctions of gastropods, reptiles, amphibians, and multituberculate mammals. Many modern mammal groups begin to appear: first glyptodonts, ground sloths, canids, peccaries, and the first eagles and hawks. Diversity in toothed and baleen whales. 33 Ma
Here is a list of examples in which unrelated proteins have similar functions with different structure. The convergent orientation of the catalytic triad in the active site of serine and cysteine proteases independently in over 20 enzyme superfamilies. [252] The use of an N-terminal threonine for proteolysis.
Comparative anatomy is the study of similarities and differences in the anatomy of different species. It is closely related to evolutionary biology and phylogeny [1] (the evolution of species). The science began in the classical era, continuing in the early modern period with work by Pierre Belon who noted the similarities of the skeletons of ...
Sauropsida (Greek for "lizard faces") is a clade of amniotes, broadly equivalent to the class Reptilia, though typically used in a broader sense to also include extinct stem-group relatives of modern reptiles and birds (which, as theropod dinosaurs, are nested within reptiles as more closely related to crocodilians than to lizards or turtles). [2]
Comparative embryology offered not only powerful arguments in support of a branching order of nature, but also powerful insights into the deep relationships between natural groups of organisms such as reptiles, birds, and mammals. In fact, Darwin found comparative embryology to offer a key to the recognition of common ancestry.
e. Reptiles arose about 320 million years ago [1] during the Carboniferous period. Reptiles, in the traditional sense of the term, are defined as animals that have scales or scutes, lay land-based hard-shelled eggs, and possess ectothermic metabolisms. So defined, the group is paraphyletic, excluding endothermic animals like birds that are ...