Annelids Vs Roundworms: 15 Crucial Differences & Similarities

These creatures are invertebrates with elongated bodies. They both exhibit bilateral systems and have a complete digestive system.

So, what is the main difference between annelids and roundworms? Annelids are segmented worms whereas roundworms are not segmented.

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Comparison Table (Annelids vs Roundworms)

Basic Terms Annelids Roundworms
Definition These are segmented worms that belong to the phylum Annelida. These are cylindrical worms whose body has tapered ends
Body Structure Most complex body plan Medium complex body plan
Mesoderm Have a well-developed mesoderm Do not have mesoderm
Coelom Have a true coelom Have a pseudo coelom
Location of Organs Organs are separated from the coelom cavity Organs are bathed in the fluid of the body cavity
Segmentation Have segmented body The body is not segmented
Body Ends Do not have tapered ends in their body Have tapered body ends
Body length 8-10 inches long 4 feet long
Circulatory system Have a complete circulatory system e.g heart, blood, and vessels Have an incomplete circulatory system. Nutrients move through a diffusion
Muscles Have both longitudinal and circular muscle Have circular muscle
Eyes Have eyespots Have more complex eyes
Cuticle Do not have a cuticle Have cuticle made up of collagen
Gender Tend to be hermaphrodites Tend to have separate sexes
Habitat Most live in the soil Live in both plants and animals
Mode of nutrition Communalism Parasitism
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What Are Annelids?

These are invertebrate worms with segmented bodies. These creatures have blunt end bodies and they feed on decaying organic matters.

These worms tend to live in freshwater, saltwater, and moist terrestrial environment. These worms secrete cuticles on their skin which are made up of collagen.

Research shows that annelids have a complete circulatory system that comprises blood, blood vessels, and the heart.

What Are Roundworms?

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. They obtain nutrients from the host.

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Main Difference between Annelids and Roundworms

  1. Annelids have segmented bodies while roundworms have cylindrical bodies
  2. Annelids have a complete circulatory system whereas roundworms have an incomplete circulatory system
  3. Annelids have a true coelom while roundworms have a pseudo coelom
  4. Annelids have blunt-body ends whereas roundworms have tapered body ends
  5. Roundworms have separate sexes whereas annelids are hermaphrodites
  6. Annelids have a rigid cuticle made of collagen whereas roundworms do not secrete cuticle
  7. Roundworms have longitudinal muscles whereas annelids have both longitudinal and circular muscles
  8. Annelids have eyespots whereas roundworms have more complex eyes
  9. Annelids have about 8-10 inches long whereas roundworms are about 4 feet long
  10. Annelids have well-developed mesoderm whereas roundworms do not have mesoderm
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Similarities between Annelids and Roundworms

  1. Both are invertebrates with elongated bodies
  2. Both exhibit bilateral symmetry
  3. Both have a complete digestive system
  4. Both are either free-living or parasites in plants and animals

Annelids vs Roundworms FAQs

What Is the Most Important Role Of Annelids?

These creatures are responsible for the aeration of the soil and sediments. This helps to increase the fertility of the soil for agricultural purposes.

Do Roundworms Have Eyes?

Yes. However, they have a more complex eye. The good news is that they have a strong sense of light. Hence, can survive perfectly in animals’ intestines.

What Do Roundworms Have That Flatworms Do Not?

Roundworms have cylindrical bodies with tapered ends whereas flatworms have bodies covered with cilia or hair-like growth.

How Do I Know If I Have Roundworms?

Live worms in the feces, wheezing, cough, fever, severe abdominal pain, vomiting, restlessness, and disturbed sleep.

What is special about the body structure of the annelid?

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These creatures have a worm shape with segmented bodies. Besides that, the body secretes a thick protective substance known as the cuticle.

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The core difference between nematodes and annelids is that nematodes have cylindrical bodies with tapered ends whereas annelids have a more complex body that is segmented.

The good news is that these invertebrates exhibit bilateral symmetry and a certain degree of impact in the ecological niche. Annelids are beneficial whereas roundworms are infectious.

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