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The adult forms of both tunicates and lancelets are in face sessile creatures, as they are extremely docile and they spend most of their time either asleep or on the prowl for food, but never living food.
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What is the significance of Protochordates?
The name Protochordates literally means 'the first chordates.' The chordates include fish, amphibians, reptiles, birds and mammals. The protochordates fall into two broad groups or subphyla - the Urochordata and the Cephalochordata. Urochordata The urochordata includes the group known as the tunicates - animals whose free-swimming larvae have a notochord* and a nerve chord. The adults are sessile - that is to say they are anchored to one place on the Reef. CephalochordataCephalochordates, or lancelets, are fish-like animals that have a notochord and nerve chord along the entire length of their bodies and which persist all their lives. * A notochord is a an elongated cellular chord enclosed in a sheath, that forms the primitive skeleton of chordate embryos (including humans) and adult cephalochordates. The name Protochordates literally means 'the first chordates.' The chordates include fish, amphibians, reptiles, birds and mammals. The protochordates fall into two broad groups or subphyla - the Urochordata and the Cephalochordata. Urochordata The urochordata includes the group known as the tunicates - animals whose free-swimming larvae have a notochord* and a nerve chord. The adults are sessile - that is to say they are anchored to one place on the Reef. Cephalochordata Cephalochordates, or lancelets, are fish-like animals that have a notochord and nerve chord along the entire length of their bodies and which persist all their lives. * A notochord is a an elongated cellular chord enclosed in a sheath, that forms the primitive skeleton of chordate embryos (including humans) and adult cephalochordates.
What animal exhibits all four chordate features an adult?
The adult tunicate, specifically the subphylum Urochordata, exhibits all four chordate features: a notochord, dorsal nerve cord, pharyngeal slits, and post-anal tail. While tunicates are more commonly recognized in their larval stage, which displays these features prominently, certain adult tunicate forms retain these characteristics in a reduced or modified state. For example, they have a notochord in their larval stage, and some adult forms retain remnants of the nerve cord and pharyngeal slits for filter feeding. Thus, while tunicates are unique among chordates, they do reflect the chordate features in their life cycle.
What are two forms of cnidrians?
The two forms of Cnidarians are the Medusoid or mobile form (e.g. Hydra), and the Polyp or sessile form (e.g. Aurelia).
Two main forms of life for the cnidarians?
Polyps, which are Sessile or stationary, and Medusa which move.
Are cnidaria symmetrical?
Cnidaria have two basic body forms: swimming Medusae and sessile Polyps, and they are both radially symmetrical.
What does the knobby sea star eat?
It eats especially sessile life forms include hard corals and sponges in aquarium.
Did a coral spends their adult lives as Medusa?
Corals do not spend their adult lives as medusae. Instead, they primarily exist as polyps, which are sessile, cylindrical forms that attach to the substrate and form coral reefs. The medusa stage is typically associated with the life cycle of jellyfish, which are part of the same phylum, Cnidaria, but corals do not develop into medusae in their adult form. Some corals may have a medusa stage in their reproductive cycle, but they predominantly remain as polyps throughout their lives.
What are the characteristics of the phylum Chordata?
There are three subphylums in Chordata. Two of them are invertebrates - Urochordata (tunicates) and Cephalachordata (lancelets), while the third is Vertebrata (vertebrates). This phylum includes all animals which have a hollow dorsal nerve cord and a notochord at some stage during their development. In the case of vertebrates, the notochord is present in the embryo, and develops into the vertebral body. In the tunicates, the adult form no longer has the notochord. Another characteristic they share is that, at some stage during their lives, they have pharyngeal grooves and pouches that develop into other essential parts of their anatomy (many textbooks still state that all vertebrate embryos have gill slits, but there has been a great deal of development in the science of embryology to refute this claim). Chordates all have a post-anal tail, which means an extension of the notochord and nerve chord behind the anus, although this feature is no longer present in the mature forms of some creatures such as frogs, and some mammals such as people. Chordates also have a closed circulatory system, although not all Chordates have an actual heart like the vertebrate Chordates do. They have chevron shaped musculature; are deuterostomes, meaning they have two openings to the alimentary canal, and have three coelomic (body) cavities. They have segmentation which is seen in the arrangement of muscles and in the vertebral column.
What is the adult size of a dragonfly insect?
Any dragonfly you see is already an adult. The juvenile forms have no resemblance to the adult form.
What do all animals in chordata have in common?
There are three subphylums in Chordata. Two of them are invertebrates - Urochordata (tunicates) and Cephalachordata (lancelets), while the third is Vertebrata (vertebrates). This phylum includes all animals which have a hollow nerve cord and a notochord at some stage during their development. In the case of vertebrates, the notochord is present in the embryo, and develops into the vertebral body. In the tunicates, the adult form no longer has the notochord. Another characteristic they share is that, at some stage during their lives, they have pharyngeal grooves and pouches that develop into other essential parts of their anatomy (many textbooks still state that all vertebrate embryos have gill slits, but there has been a great deal of development in the science of embryology to refute this claim). Chordates all have a post-anal tail, which means an extension of the notochord and nerve chord behind the anus, although this feature is no longer present in the mature forms of some creatures such as frogs, and some mammals such as people. Chordates also have a closed circulatory system, although not all Chordates have an actual heart like the vertebrate Chordates do.
The variation in the forms of adult vertebrates probably arose through mutations in genes?
the variation in the forms of adult vertebrates probably arose through mutations in dominant genes
Is obelia a motile coelenterate?
Obelia is a type of colonial coelenterate, specifically belonging to the class Hydrozoa. It exhibits both motile and sessile forms during its lifecycle; the medusa stage is free-swimming and motile, while the polyp stage is attached to a substrate and sessile. Therefore, while Obelia has a motile phase, it is not entirely motile as a whole organism.
