Do flatworms have an eyespot?


Do flatworms have an eyespot?

Planarian flatworms, which often live in dark, watery environments shielded from direct light, don’t have complex eyes like we do. But many do have two lensless, primitive “eyespots” on their heads that can detect the intensity of light.

What is an eyespot flatworm?

Flatworms’ bodies are bilaterally symmetrical and they have a defined head and tail region. They have a central nervous system containing a brain and a nerve cord. Clusters of light-sensitive cells on either side of their head make up what are called eyespots.

Do free living worms have eyespots?

Dugesia, as well as most free-living flatworms, move over surfaces by means of cilia on their ventral surface. Note the pigmented eye spots, or ocelli, located on the triangular “head” of the animal. These eye spots are sensitive only to light and dark, and are unable to resolve images.

What type of symmetry do roundworms have?

Roundworms (nematodes) are bilaterally symmetrical, worm-like organisms that are surrounded by a strong, flexible noncellular layer called a cuticle. Their body plan is simple.

Do roundworms have a complete digestive system?

Unlike the flatworms, the roundworms have a body cavity with internal organs. A roundworm has a complete digestive system, which includes both a mouth and an anus. The last portion of the intestine forms a rectum, which expels waste through the anus. Roundworms also have a simple nervous system with a primitive brain.

Do roundworms have cephalization?

Compare and contrast the body plans of flatworms with roundworms. Similarities: Both have three germ layers and bilateral symmetry. They both have anterior and posterior ends allowing cephalization to occur. A roundworm has fluids that circulate through the body; a flatworm does not.

What stimulus can a flatworm detect?

A. Which stimulus would a flatworm be able to detect? The smell of prey.

Are roundworms free-living or parasitic?

Roundworms in the Environment Roundworms can be free-living organisms, but they are probably best known for their role as significant plant and animal parasites. Most Nematodes are parasitic, with over 16,000 parasitic species described.

Are earthworms free-living or parasitic?

Earthworms (class Oligochaeta) are familiar terrestrial members of this phylum and leeches (class Hirudinea) are well-known parasitic members of the phylum, most commonly found in freshwater. The polychaete worms or “bristleworms” (class Polychaeta) are the largest group in the phylum Annelida.

Do roundworms have appendages?

Nematodes (roundworms) are colorless, unsegmented, and do not have appendages. Nematodes may be free-living, predaceous, or parasitic, and many of the parasitic species cause important diseases of plants, animals, and humans.

Do roundworms have a notochord?

Their predecessors are represented by fossils from those Cambrian seas: worm-like animals like Pikaia and Haikouella. These animals are not vertebrates, but they do possess a notochord. They belong in a more inclusive category called the chordates, which incorporates vertebrates and a few vertebrate-like groups.

What happens if your dog has roundworms?

Most pets show no signs of infection with these worms, but some may vomit, stop eating their food, or lose weight. Heavy infections in young puppies and kittens may lead to death. * The word “roundworms” refers here to a group of worms known as ascarids.

What are the symptoms of a roundworm infection?

Symptoms of the infection in the stomach are diarrhea, abdominal cramps, and tiredness. When the larvae enter the muscle fibers you may feel muscle aches and pains, high fever, swelling in the eyes and face, eye infection and rashes.

What kind of worms have tapered ends and tapered eyes?

These are invertebrate worms with cylindrical bodies. These creatures have tapered ends and the mode of nutrition is parasitic. The worms tend to live in plants and animals. They normally have separate sexes and are also known as nematodes. Research shows that these worms have circular muscles and more complex eyes.

Where do roundworms come from and how are they treated?

Often, roundworm infections come from traveling to countries with poor sanitation and hygiene. But kids can get them in the U.S. too. Medication can treat roundworms. What are roundworms? Roundworms are small organisms that can live in your intestines, part of your digestive system for a long time.

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