What are five characteristics of phylum Platyhelminthes?

Characteristic features of Phylum Platyhelminthes

• Their body is dorsoventrally flattened.
• They exhibit bilateral symmetry.
• Also, they are triploblastic, with three germ layers.
• They do not have a body cavity and are acoelomate.
• The body is soft and unsegmented.
• They are mostly parasitic with a few free-living.

What is parasitic Platyhelminthes?

flatworm, also called platyhelminth, any of the phylum Platyhelminthes, a group of soft-bodied, usually much flattened invertebrates. A number of flatworm species are free-living, but about 80 percent of all flatworms are parasitic—i.e., living on or in another organism and securing nourishment from it.

Why Platyhelminthes are parasites?

The Platyhelminthes, both parasitic and free-living taxa, share a set of characters: they are nonsegmented acolomates without an anus, which lack respiratory and circulatory systems but possess an excretory system. In addition, all are hermaphroditic and asexual (mainly paratomy) and sexual reproduction are present.

Which class is an external parasite which infects aquatic hosts?

monogeneans
Unlike the other parasitic groups, the monogeneans are external parasites infesting aquatic animals, and their larvae metamorphose into the adult form after attaching to a suitable host.

What are the peculiar features that you find in parasitic platyhelminthes?

Peculiar features in parasitic platyhelminthes are as follows:

• They have dorsoventrally flattened body and bear hooks and suckers to get attached inside the body of the host.
• Their body is covered with thick tegument, which protects them from the action of digestive juices of the host.

Why do flatworms need to be flat?

They have a flat body because they do not have a coelom or even a pseudocoelom. They also lack a respiratory system. Instead, their cells exchange gases by diffusion directly with the environment. The mesoderm layer allows them to develop organ systems.

What parasite looks like a stick?

Horsehair worms, part of the taxonomic phylum Nematomorpha, are parasitic worms that resemble long thin strands of hair (hence their nickname).

Why are Platyhelminthes flat?

Flatworms range in length from about 1 millimeter (0.04 inches) to more than 20 meters (66 feet). They have a flat body because they do not have a coelom or even a pseudocoelom. They also lack a respiratory system. Instead, their cells exchange gases by diffusion directly with the environment.

What are the benefits to a worm of being Dorsoventrally flattened?

Flatworms are also dorsoventrally flattened, ensuring the diffusion of oxygen and nutrients to their tissues. Despite this constraint, the absence of a cuticle, exoskeleton or shell has allowed these soft-bodied worms to adopt a dizzying array of shapes, body plans and sizes (Figure 1B–O).

Why are platyhelminthes flat?

Are flattened elongated worm like animals?

One type of worm is the flatworm. Worms in the phylum Platyhelminthes are called flatworms because they have flattened bodies.

Is Ribeiroia a trematode?

Ribeiroia (/raɪˈbɪəriːə/) is a genus of trematode parasites that sequentially infect freshwater snails in the family Planorbidae (ramshorn snails) as first intermediate hosts, fish and larval amphibians as second intermediate hosts, and birds and mammals as definitive hosts (see § Life history).

What are the characteristics of Ribeiroia?

All species of Ribeiroia share the distinctive morphological characteristic of esophageal diverticula (i.e., two short dead-end branches that extend laterally from the esophagus ). Other genera closely related to Ribeiroia include Cladocystis trifolium, Cathemasia, and Echinostoma (Johnson et al. 2004).

What is the scientific name for Ribeiroia?

Ribeiroia ( / raɪˈbɪəriːə /) is a genus of trematode parasites that sequentially infect freshwater snails in the family Planorbidae (ramshorn snails) as first intermediate hosts, fish and larval amphibians as second intermediate hosts, and birds and mammals as definitive hosts (see § Life history ).

What is the life cycle of Ribeiroia ondatrae?

Ribeiroia ondatrae has an indirect complex life cycle. The adult worms live inside predatory birds or mammals (the definitive hosts), wherein they reproduce sexually if other worms are present. Mature adults release eggs into the host’s intestinal tract, which are passed with the feces of the host, and to develop need to end up in water.