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Hace 4 días · 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.
Hace 2 días · It is a paraphyletic grouping including all animals excluding the chordate subphylum Vertebrata, i.e. vertebrates. Well-known phyla of invertebrates include arthropods, mollusks, annelids, echinoderms, flatworms, cnidarians, and sponges. The majority of animal species are invertebrates; one estimate puts the figure at 97%.
Hace 5 días · Olfactores is a clade within the Chordata that comprises the Tunicata (Urochordata) and the Vertebrata (sometimes referred to as Craniata). Olfactores represent the overwhelming majority of the phylum Chordata, as the Cephalochordata are the only chordates not included in the clade.
Hace 4 días · Largest and heaviest animals. Clockwise from top left: an African bush elephant, the largest extant terrestrial animal; a blue whale, the largest animal ever to exist; and a colossal squid, the largest invertebrate. The largest animal currently alive is the blue whale.
Hace 3 días · Birds are a group of warm-blooded vertebrates constituting the class Aves ( / ˈeɪviːz / ), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweight skeleton.
Hace 4 días · Reptiles, as commonly defined, are a group of tetrapods with an ectothermic ('cold-blooded') metabolism and amniotic development. Living reptiles comprise four orders: Testudines ( turtles ), Crocodilia ( crocodilians ), Squamata ( lizards and snakes ), and Rhynchocephalia (the tuatara ). As of May 2023, about 12,000 living species of reptiles ...
Hace 4 días · The hagfish eye lacks a lens, extraocular muscles, and the three motor cranial nerves (III, IV, and VI) found in more complex vertebrates, which is significant to the study of the evolution of more complex eyes. A parietal eye is also absent in extant hagfish.
