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Because Annelids have much more "complicated" characteristics such as, The body possesses 3 separate sections of themselves, have a closed Circulatory system, and has a nervous system with an interior nerve ring, ganglia & ventral cord. As nematodes and Platyhelminthes have very simple characteristics:
Nematodes: Bilaterally symmetrical, feeds on just about everything, lives just about anywhere, and has no circulatory system.
Platyhelminthes: do not have an anus, have a sac-like body, contain a hydrostatic skeleton and sexually reproduce.

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11y ago
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5mo ago

Annelids have a more complex body plan than nematodes and platyhelminthes because they have segmented bodies with specialized structures like bristles (setae) and a closed circulatory system. This segmentation allows for more specialized functions in different body regions, giving annelids a higher level of complexity compared to the more simple, unsegmented body plans of nematodes and platyhelminthes.

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15y ago

It has more parts and does more stuff.

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Q: Why are annelids more complex than nematodes and platyhelminthes?
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What features distinguish annelids from roundworms?

There's many of them, but here are some of the bigger ones; Annelids, unlike roundworms (or flatworms for that matter) are segmented. That is after all how they get their name (annelida = little ring). Annelids also have a very complex organ system. Roundworms only possess a reproduction system as they usually live in an organism's intestines and don't need to digest food. Annelids posses both a reproduction system, and a digestive system as well as a circulatory system. As they are true coelomates their organs and organ systems are organised rather than just kinda' being tossed in there. =)


What is a invertibrite?

The animals which don't have vertebral column are called invertebrates. They are 1) poriferans 2) Coelenterates 3) Platyhelminthes 4) Nematyhelminthes 5) Annelids 6) Arthropods 7) Molluscs 9) Echinodermates


What are the examples of the phylum platyhelminthes?

Did you know, potentially life-endangering parasites can live in the human body for up to several decades? Moreover, these parasites, known as blood flukes, have the ability to regenerate themselves. And so, can survive in hostile environments. Furthermore, these worms belong to Phylum Platyhelminthes. Let us explore this phylum. visit our page : theconvergencetech .com


Is it true that the more genes you have the more complex of an organism you are?

Not necessarily. The number of genes does not directly correlate with complexity. For example, humans have around 20,000-25,000 genes, while some plants have a lot more. Complexity is more influenced by how genes are regulated and interact with each other.


Are all living things complex?

No, not all living things are complex. Some living organisms, like bacteria and single-celled organisms, are relatively simple in structure and function compared to more complex organisms like plants and animals. Complexity in living things can vary greatly depending on the species and their evolutionary history.

Related questions

How are earthworms and ascaris similar?

Annelids are segmented whereas roundworms are not. Annelids have a true coelom while roundworms have a pseudocoelom. Annelids have a more complex nervous system than roundworms. Annelids have a more complex circulatory system than roundworms.


Where can one find more information about nematodes?

Nematodes are roundworms. Many of the 28,000 or more species of nematodes are parasitic. Nematodes are very successful organisms, living just about everywhere where there is life.


Annelids are the first of the animal phyla studied to have what general characteristic?

Annelids are the first animal phyla to have a true body cavity (coelom), which is enclosed by mesoderm. This cavity enables more complex organ systems and allows for greater specialization of body functions.


How do platyhelminths differ from nemathelminths?

Brief answer only. Phyllum Platyhelminthes are the flatworms. These have three layers of cells. Phyllum Annelidia are the segmented worms. These have blood vessels, a developed nervous system, and a digestive system organized round a central tube.


What features distinguish annelids from roundworms?

There's many of them, but here are some of the bigger ones; Annelids, unlike roundworms (or flatworms for that matter) are segmented. That is after all how they get their name (annelida = little ring). Annelids also have a very complex organ system. Roundworms only possess a reproduction system as they usually live in an organism's intestines and don't need to digest food. Annelids posses both a reproduction system, and a digestive system as well as a circulatory system. As they are true coelomates their organs and organ systems are organised rather than just kinda' being tossed in there. =)


Do flatworms have many cells?

No, flatworms are multicellular organisms with a simple body plan, but they do not have many cells compared to more complex organisms. They typically have around a few thousand to a few million cells.


How many species of annelids have been discovered?

There are more than 22,000 recognized species of annelids, which are segmented worms commonly found in marine, freshwater, and terrestrial environments.


Do nematodes molt?

Yes, nematodes molt as they grow. They shed their exoskeleton through a process called ecdysis in order to accommodate their increasing size. Nematodes molt several times during their life cycle.


What was one of the first animals to develop a true body cavity?

One of the first animals to develop a true body cavity was roundworms, also known as nematodes. This body cavity, called a pseudocoelom, helped provide support and structure to their bodies, allowing for more efficient movement and organ function.


What is the difference between nematodes and other worms?

Nematodes are triploblastic (they have an ectoderm, mesoderm and endoderm) but also have a pseudocoelom (a closed fluid-containing cavity that acts as a hydrostatic skeleton to maintain body shape, circulate nutrients, and hold the major organs). They have a thick cuticle covering their body to protect them from digestion. Just inside their gut are the longitudinal muscles; unlike other worms (annelids), the nematodes lack a circular muscle and so their movement is restricted to a side-to-side whip. The female reproductive system consists of two highly folded ovaries and two oviducts that store eggs Annelids (other worms) are also triploblastic. They are coelomate where the coelom is divided into segments and each segment can move independently. The most distinguishing feature of this group is segmentation, with the segments visible as rings around the body. Movement is by their circular muscles which expand and contract, moving the animal forward as well as side to side. Movement is also aided by the presence of bristles along the body. So basically the main difference in the two phylum is the presence or lack of circular muscle which is an important evolutionary step in annelids as it allows more effective movement.


What are the types of coelom of platyhelminthes?

Platyhelminthes have an acoelomate body plan, which means they lack a true coelom. Instead, they have a solid body with a more primitive digestive cavity and lack a fluid-filled body cavity like true coelomates.


What is the most common name for flatworms?

The flatworm's scientific name (or at least its Phylum) is Platyhelminthes. I can't give you the real scientific name (which is the genus and species) because there are more than one species of flatworm.