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They show bilateral symmetry and remarkable contractile properties. Because of their contractility, they can change their morphological presentation in response to environmental cues. Animals in phylum Nemertea show a flattened morphology, that is, they are flat from front to back, like a flattened tube.
- Do ribbon worms have bilateral symmetry?
- Do Nemertea have a true Coelom?
- What is the common example of phylum Nemertea?
- Do Nemertea have hearts?
- How do Nemertea reproduce?
- Is Nemertea a Pseudocoelomate?
- Do flatworms have a proboscis?
- What do Marine ribbon worms eat?
- Is the Rhynchocoel a true Coelom?
- Does Nemertea have nerves?
- Is Nemertea segmented?
- Where can you find Nemertea?
- Do Nemertea have a Lophophore?
- Is Nemertea a Coelomate?
- What type of circulatory system do annelids have?
Do ribbon worms have bilateral symmetry?
The general body plan of ribbon worms is very similar to that of turbellarians. They exhibit bilateral symmetry and have a body shape that is cylindrical anteriorly yet flattened posteriorly. The body of a ribbon worm is triploblastic, meaning they have three layers of tissue (endoderm, mesoderm, and ectoderm).
Do Nemertea have a true Coelom?
Flatworms (phyla Platyhelminthes, Nemertea, and Mesozoa) lack a coelom, although nemerteans have a fluid-filled...…
What is the common example of phylum Nemertea?
The carnivorous marine ribbon worms or nemertines (Phylum Nemertea or Phylum Rhyncocoela) are predators of snails, small crustaceans, mollusks, and polychaetes.
Do Nemertea have hearts?
Nemerteans respire through the skin. They have at least two lateral vessels which are joined at the ends to form a loop, and these and the rhynchocoel are filled with fluid. There is no heart, and the flow of fluid depends on contraction of muscles in the vessels and the body wall.
How do Nemertea reproduce?
Most Nemertea reproduce by sexual reproduction, being either male or female. However some freshwater and terrestrial species are hermaphroditic and can be self fertilising. In a very few species, the eggs are retained within the female and hatch as small copies of the adult to then be released into the world.
Is Nemertea a Pseudocoelomate?
The nemertini are the simplest eucoelomates. These ribbon-shaped animals bear a specialized proboscis enclosed within a rhynchocoel. The development of a closed circulatory system derived from the coelom is a significant difference seen in this species compared to other pseudocoelomate phyla.
Do flatworms have a proboscis?
Predatory flatworms belonging to the taxon Kalyptorhynchia are characterized by an anterior muscular proboscis that they use to seize prey.
What do Marine ribbon worms eat?
Diet and Predators
Most ribbon worm species are carnivorous, feeding largely on annelids, clams, and various crustaceans such as crabs. Some species will also eat fish and many will scavenge on virtually anything they can find. The few terrestrial species of Argonemertes feed solely on insects and myriapods.
Is the Rhynchocoel a true Coelom?
rhynchocoel In Nemertini, a fluid-filled cavity containing the proboscis. Since it is of mesodermal origin, it is considered a true coelom even though its extent is limited.
Does Nemertea have nerves?
Since nearly all nemerteans are predators, their central nervous system has been considered quite uniform, composed of a four-lobed brain and two lateral medullary cords which originate from the ventral lobes of the brain and extend the whole length of the animal until they converge at the posterior tip of the animal [ ...
Is Nemertea segmented?
Taxonomic level: phylum Nemertea; grade of construction: organs derived from three tissue layers; symmetry: bilateral; type of gut: complete, with anus; type of body cavity other than gut: rhynchocoel surrounding proboscis; segmentation: absent; circulatory system: present; nervous system: small bundles of nerves ( ...
Where can you find Nemertea?
Nemertea is a phylum of invertebrate animals also known as ribbon worms or proboscis worms. Most of the 1,400 or so species are marine, with a few living in fresh water and a small number of terrestrial forms. They live in all marine habitats, and throughout the world's oceans.
Do Nemertea have a Lophophore?
The flatworms possess neither a lophophore nor trochophore larvae, although the larvae of one group of flatworms, the Polycladida (named after its many-branched digestive tract), are considered to be homologous to trochophore larvae.
Is Nemertea a Coelomate?
The results firmly placed nemerteans with mollusks and annelids in lophotrochozoa (Figure 4). This means that the rhynchocoel and contractile blood vessels found in nemerteans are in fact true coeloms, and implies that an acoelomate form truly is basal, and coelomate forms more derived.
What type of circulatory system do annelids have?
Annelida. While some small segmented worms of the phylum Annelida have no separate circulatory system, most have a well-developed closed system.
