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Amphibians are ectothermic, anamniotic, four-limbed vertebrate animals that constitute the class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all tetrapods excluding the amniotes (tetrapods with an amniotic membrane, such as modern reptiles, birds and mammals).
Goat kids will stay with their mother until they are weaned. Most mammals are viviparous, giving birth to live young. [1] However, the five species of monotreme, the platypuses and the echidnas, lay eggs. The monotremes have a sex determination system different from that of most other mammals. [2]
Ossea Batsch, 1788[2] Vertebrates (/ ˈvɜːrtəbrɪts, - ˌbreɪts /) [3] are deuterostomal animals with bony or cartilaginous axial endoskeleton — known as the vertebral column, spine or backbone — around and along the spinal cord, including all fish, amphibians, reptiles, birds and mammals.
While the early amniotes resembled their amphibian ancestors in many respects, a key difference was the lack of an otic notch at the back margin of the skull roof. In their ancestors, this notch held a spiracle , an unnecessary structure in an animal without an aquatic larval stage. [ 25 ]
Shark. † Synechodontiformes. Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimorpha[1] (or Selachii) and are the sister group to the Batoidea (rays and kin).
Aquatic mammal. An Amazon river dolphin (Inia geoffrensis), a member of the infraorder Cetacea of the order Cetartiodactyla. Aquatic mammals and semiaquatic mammals are a diverse group of mammals that dwell partly or entirely in bodies of water. They include the various marine mammals who dwell in oceans, as well as various freshwater species ...
Amphibians like frogs and toads can vocalise using vibrating tissues in airflow. For example, frogs use vocal sacs and an air-recycling system to make sound, while pipid frogs use laryngeal muscles to produce an implosion of air and create clicking noise. [7] Aquatic mammals such as seals and otters can produce sound using the larynx.
Aquatic locomotion. A great cormorant swimming. Aquatic locomotion or swimming is biologically propelled motion through a liquid medium. The simplest propulsive systems are composed of cilia and flagella. Swimming has evolved a number of times in a range of organisms including arthropods, fish, molluscs, amphibians, reptiles, birds, and mammals.