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Vertebrates (/ ˈ v ɜːr t ə b r ɪ t s,-ˌ b r eɪ t s /) [3] are animals with a vertebral column (backbone or spine), and a cranium, or skull.The vertebral column surrounds and protects the spinal cord, while the cranium protects the brain.
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.
Ralph Morris Buchsbaum (January 2, 1907 – February 11, 2002) was an American zoologist, invertebrate biologist, and ecologist.His book Animals Without Backbones, first published in 1938, was the first textbook in biology to be reviewed by Time and featured in Life.
An extinct ribbonlike sea creature about the size of a human thumb was one of the earliest animals to evolve a precursor of a backbone. Scientists recently identified the animal’s nerve cord by ...
This is a list of various species of marine invertebrates, animals without a backbone, that are commonly found in aquariums kept by hobby aquarists. Some species are intentionally collected for their desirable aesthetic characteristics. Others are kept to serve a functional role such as consuming algae in the aquarium.
A chordate (/ ˈ k ɔːr d eɪ t / KOR-dayt) is a 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.
An ancient synapsid, Dimetrodon, had extremely long spines on its backbone that were joined together with a web of skin that formed a sail-like structure. Many mammalian species, like cats and fossas, [1] [2] also have penile spines. The Mesozoic eutriconodont mammal Spinolestes already displayed spines similar to those of modern spiny mice. [3]
Agnatha (/ ˈ æ ɡ n ə θ ə, æ ɡ ˈ n eɪ θ ə /; [3] from Ancient Greek ἀ-(a-) 'without' and γνάθος (gnáthos) 'jaws') is a paraphyletic infraphylum [4] of non-gnathostome vertebrates, or jawless fish, in the phylum Chordata, subphylum Vertebrata, consisting of both living (cyclostomes) and extinct (conodonts, anaspids, and ostracoderms, among others).