Search results
Results from the WOW.Com Content Network
Amphibians have soft bodies with thin skins, and lack claws, defensive armour, or spines. Nevertheless, they have evolved various defence mechanisms to keep themselves alive. The first line of defence in salamanders and frogs is the mucous secretion that they produce. This keeps their skin moist and makes them slippery and difficult to grip.
Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a spine or backbone), which evolved from the notochord.It is a paraphyletic grouping including all animals excluding the chordate subphylum Vertebrata, i.e. vertebrates.
In the 10th edition of Systema Naturae, Carl Linnaeus described the Amphibia as: [1]. Animals that are distinguished by a body cold and generally naked; stern and expressive countenance; harsh voice; mostly lurid color; filthy odor; a few are furnished with a horrid poison; all have cartilaginous bones, slow circulation, exquisite sight and hearing, large pulmonary vessels, lobate liver ...
Class Amphibia (amphibians, some ancestral to the amniotes)—now a paraphyletic group; Class Synapsida (mammals and their extinct relatives) Class Sauropsida (reptiles and birds) While this traditional taxonomy is orderly, most of the groups are paraphyletic, meaning that the structure does not accurately reflect the natural evolved grouping. [47]
Instead of true vertebrae, they have a series of cartilaginous structures called arcualia arranged above the notochord. Hagfish, which resemble lampreys, have traditionally been considered the sister taxon of the true vertebrates (lampreys and gnathostomes) [36] but DNA evidence suggests that they are in fact the sister taxon of lampreys. [37]
A chordate (/ ˈ k ɔːr d eɪ t / KOR-dayt) is a deuterostomal bilaterian animal belonging to the phylum Chordata (/ k ɔːr ˈ d eɪ t ə / kor-DAY-tə).All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (synapomorphies) that distinguish them from other taxa.
Amphibians are in decline worldwide, with 2 out of every 5 species threatened by extinction, according to a paper published Wednesday in the scientific journal Nature.
The temnospondyl Eryops had sturdy limbs to support its body on land Red-eyed tree frog (Agalychnis callidryas) with limbs and feet specialised for climbing Japanese giant salamander (Andrias japonicus), a primitive salamander The bright colours of the common reed frog (Hyperolius viridiflavus) are typical of a toxic species Wallace's flying frog (Rhacophorus nigropalmatus) can parachute to ...