What are three characteristics of ribbon worms?
Phylum Nemertea (Ribbon Worms)
- Bilaterally symmetrical and dorsoventrally flattened.
- Body has more than two layers of cells with tissues and organs.
- Body has a through gut with a mouth and anus.
- Body has no body cavity.
- Has a blood system with blood vessels.
- Has a well developed nervous system and a brain.
What are the basic characteristics of ribbon worms?
The ribbon worms are the simplest animals to possess a circulatory system and a gut with a separate mouth and anus. The body is usually long and slender and is often extended greatly during movement.
Where are ribbon worms located?
Ribbon worms, or nemerteans, are a group of very unusual worms related to mollusks and annelids. Most ribbon worms live in the ocean, and some can grow to over 100 feet long, but are usually much less than an inch wide. Some species live on land or in freshwater. Unlike annelids, ribbon worms are not segmented.
Are ribbon worms Deuterostomes?
They found that ribbon worms and horseshoe worms are evolutionarily closely related, despite looking very different. Surprisingly, the researchers found that these worms, which are protostomes, share many gene families and gene arrangements with the deuterostomes, the group that includes the vertebrates.
What kind of body does a ribbon worm have?
Ribbon worm. The body is usually long and slender and is often extended greatly during movement. Most species are less than 20 cm (8 inches) long, but the giant species Lineus longissimus may reach a length of 30 m (100 feet). Some forms that swim in deep water are flat and broad, with finlike appendages.
How big does a nemertean ribbon worm get?
Nemerteans are a unique group of organisms that have a significant ecological role. The typical ribbon work is slim and long. The smallest species measure just a few millimeters in length and most are less than 8 inches long.
Is the ribbon worm a true coelom or coelom?
In general, the ribbon worms are regarded as a distinct phylum at the highest point of acoelomate (without a body cavity) development; however, some evidence suggests that one proboscis cavity, or rhynchocoel, may be a true coelom.
Which is bigger a blue whale or a ribbon worm?
Not only is it the largest species of ribbon worm, but it may be longer than the blue whale, making it the longest animal in the world. Despite being only a few centimeters wide, this species has been regularly measured at lengths of over 100 feet and in some cases has been thought to grow to nearly 200 feet.