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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.
Segmentation in biology is the division of some animal and plant body plans into a linear series of repetitive segments that may or may not be interconnected to each other. This article focuses on the segmentation of animal body plans, specifically using the examples of the taxa Arthropoda , Chordata , and Annelida .
Spotted gar, Lepisosteus oculatus This article contains a list of all of the classes and orders that are located in the Phylum Chordata.. The subphyla Tunicata and Vertebrata are in the unranked Olfactores clade, while the subphylum Cephalochordata is not.
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. The vertebrates make up the subphylum Vertebrata with some 65,000 species, by far the largest ...
Event 540-520 Ma Pikaia. The increased amount of oxygen causes many eukaryotes, including most animals, to become obligate aerobes. The Chordata ancestor gave rise to the lancelets (Amphioxii) and Olfactores. Ancestral chordates evolved a post-anal tail, notochord, and endostyle (precursor of thyroid).
The body segments are anatomically blocks of skeletal muscles, called the myomeres, which are found in vertebrates only. No eyes can be observed. [24] The muscle orientation and flat shaped body indicate that Pikaia was an active and free swimmer. [8] It would have swum by throwing its body into a series of S-shaped, zigzag curves, as do living ...
At the very beginning of vertebrates, when they evolved from marine chordates, their evolution probably took place in fresh or slightly saline water. There is a hypothesis according to which marine fish received their kidneys after a previous adaptation of the kidneys to fresh water.
A true endoskeleton is derived from mesodermal tissue. In three phyla of animals, Chordata, Echinodermata and Porifera (), endoskeletons of various complexity are found.An endoskeleton may function purely for structural support (as in the case of Porifera), but often also serves as an attachment site for muscles and a mechanism for transmitting muscular forces as in chordates and echinoderms ...