The root of the current tree connects the organisms featured in this tree to their containing group and the rest of the Tree of Life. The basal branching point in the tree represents the ancestor of the other groups in the tree. This ancestor diversified over time into several descendent subgroups, which are represented as internal nodes and terminal taxa to the right.
The content and activities in this topic will work towards building an understanding of the phylum Chordata. Introduction to Phylum Chordata The phylum Chordata consists of animals with a flexible rod supporting their dorsal or back sides.
The phylum name derives from the Greek root word chord- meaning string. Most species within the phylum Chordata are vertebrates, or animals with backbones subphylum Vertebrata. Examples of vertebrate chordates include fishes, amphibians, reptiles, birds, and mammals.
A modern human—one species of mammal—is a familiar example of a chordate. However, we share this phylum with two groups of invertebrates as well. Tunicates subphylum Urochordata and lancelets subphylum Cephalochordata are the only invertebrate groups within the phylum Chordata.
Tunicates subphylum Urochordata are filter-feeding animals with sac-like bodies. Most tunicate species are sessile Fig. They can live either in large colonies Fig. Some species float freely as plankton with jelly-like bodies in large colonies Fig.
Lancelets subphylum Cephalochordata are arrow- or spear-shaped animals that live in shallow marine habitats, often partially buried in the sediment Fig. Chordates also have many of the most derived features we have already examined in the other phyla, such as complete digestive systems with coeloms, complex nervous systems, and respiratory and circulatory systems for efficient gas exchange.
All chordates share the following common features that are unique to the group: The notochord is a stiff but flexible rod of cells and connective tissue from the Greek root words noto meaning back and chord meaning string that gives the phylum its name, Chordata.
In some chordates the notochord is a major support structure Fig. In fishes, amphibians, reptiles, birds, and mammals, the notochord is present only in the embryo. Because bony, segmented vertebrae replace it during later stages of development, these animals are assigned to the subphylum Vertebrata.
Tunicates and lancelets are examples of invertebrate chordates since they have a notochord, but it does not develop into a vertebral column.
Pharyngeal slits are in the pharynx, the region of the digestive tract just behind the mouth Fig. In some chordates, such as tunicates, these slits filter food from the water. In other chordates, such as fish, they are respiratory structures.
In humans they appear only in the early embryo as a few indentations, not as open slits. They are therefore called pharyngeal clefts in a human embryo. The dorsal hollow nerve tube lies above the notochord Fig.The phylum Chordata contains two groups of invertebrate chordates, but the most conspicuous and familiar members of Chordata are the vertebrates.
Phylum chordata: All chordates are deuterostomes, possessing a notochord. The phylum Chordata contains all animals that possess, at some point during their lives, a hollow nerve cord and a notochord, a flexible rod between the nerve cord and the digestive track.
The phylum Chordata is an extremely diverse phylum, and the one most recognizable to us. Chordates are defined as organisms that possess a structure called a notochord, at least during some part of their development. The notochord is a rod that extends most .
Introduction. The Phylum Chordata includes the well-known vertebrates (fishes, amphibians, reptiles, birds, mammals).
The vertebrates and hagfishes together comprise the taxon Craniata. List of chordate orders. Jump to navigation Jump to search. Spotted gar, Lepisosteus oculatus. This page contains a list of all of the classes and orders that are located in the Phylum Chordata Subphylum Vetulicolia.
Banffia constricta. Phylum Chordata. This phylum is probably the most notable phylum, as all human beings and other animals and birds that are known to you, fall under this phylum.