Search results
Results from the WOW.Com Content Network
Amphibians have a skeletal system that is structurally homologous to other tetrapods, though with a number of variations. They all have four limbs except for the legless caecilians and a few species of salamander with reduced or no limbs. The bones are hollow and lightweight.
Palatal and nasal skeletal features like choanae are present in these groups and are also observed in modern amphibians. This indicates that incipient air breathing was developed, as well as modification of the hyoid arch towards stapes development. [5] These characteristics account for why osteichthyans are accepted as the sister group of ...
The jugal is a skull bone that found in most of the reptiles, amphibians and birds. In mammals, the jugal is often called the zygomatic bone or malar bone. [8] The prefrontal bone is a bone that separates the lacrimal and frontal bones in many tetrapod skulls.
Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight.Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high metabolic rates and oxygen supply, permit the bird to fly.
Unlike amphibians with internalized gills which typically rely on the changing of pressures within the buccal and pharyngeal cavities to ensure diffusion of oxygen onto the gill curtain, neotenic salamanders such as Necturus use specified musculature, such as the levatores arcuum, to move external gills to keep the respiratory surfaces ...
Frog appears to have been adapted from frosc as part of this trend. [11] Meanwhile, the word toad, first attested as Old English tādige, is unique to English and is likewise of uncertain etymology. [14] It is the basis for the word tadpole, first attested as Middle English taddepol, apparently meaning 'toad-head'. [15]
This system had evolved independently within several different amphibian lineages. The impedance matching ear had to meet certain conditions to work. The columella had to be perpendicular to the tympanum, small and light enough to reduce its inertia , and suspended in an air-filled cavity.
The evolution of tetrapods began about 400 million years ago in the Devonian Period with the earliest tetrapods evolved from lobe-finned fishes. [1] Tetrapods (under the apomorphy-based definition used on this page) are categorized as animals in the biological superclass Tetrapoda, which includes all living and extinct amphibians, reptiles, birds, and mammals.