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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.
Nash Emmerich
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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 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 organism is asymmetrical?
Asymmetry, or the absence of symmetry, most often occurs in sessile organisms or in slow-moving forms such as amebas .
What does the knobby sea star eat?
It eats especially sessile life forms include hard corals and sponges in aquarium.
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
Can scientist define life?
The usual template against which life is judged to exist or not includes: respiration; reproduction; metabolizes food; is not rigidly fixed in place (but some forms of life are rather sessile); for most species, interacts with the environment; consumes energy.
Structure of a cnidarian which contains stinging cells?
Cnidarians have simple structure; a blind ended gut, tentacles, a pharynx and several other minor organs, and gonads.
Blood is formed in human adult by?
Red bone marrow
