Earthworm vs Roundworm (Similarities and Differences)

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When you first look into the subject of worms, it can all seem a little overwhelming. Especially as lots of the animals referred to as worms, all look the same.

Roundworms and earthworms are two types of worms that a lot of people are familiar with, but to the uninitiated and untrained eye, they look very similar.

Although they are considered one and the same thing by many people, there are a lot of differences between the two.

In the following post, therefore, we are going to look at roundworms and earthworms, discussing the similarities and differences.

Is an earthworm a roundworm?

The simple answer is no. Although they are grouped under the more general term of worms, earthworms and roundworms are different species.

Before we discuss the similarities, let us address what makes earthworms different from roundworms.

Roundworms are rounder, thinner and smoother and can grow a maximum of 4-feet long.

Earthworms, on the other hand, have moist skin that is brown and can grow up to an impressive 8-feet long.

Although they both can live in soil, salt water and fresh water, only roundworms can also inhabit hosts like animals and humans, as there are several species of roundworms that are parasites.

When it comes to food and digestion, earthworms have full digestive systems and eat a diet of plants and dirt, while roundworms have definite digestive systems and consume a diet consisting of plants and other animals.

In terms of their circulatory systems, while earthworms have five working hearts, blood and blood vessels, roundworms do not have any hearts, blood vessels or even any blood

What do roundworms and earthworms have in common?

As we have already highlighted, the reason animals are broadly classified as worms, including earthworms and roundworms, is because they do have several similarities.

For one thing, all worms are invertebrates.

That is, they do not have a vertebral column, otherwise known as a backbone.

Invertebrates tend to either have bodies with a hard external casing like crabs and spiders, or a soft body like jellyfish and worms, to name a few.

They also do not have any legs and have long winding, and narrow bodies which they use to slither along whatever terrain they are in.

It is also interesting to note, that although internally they have a lot of differences when it comes to their hearts, blood, and blood vessels, they also share some similarities in this department.

For instance, all worms have organ systems, organs (other than the heart) and tissues.

They also share similarities in terms of respiration.

Roundworms and earthworms do not have any respiration system.

Both of these types of worms absorb oxygen through their skin and excrete carbon dioxide.

physical adaptations of roundworms

How are annelid worms different from flatworms and roundworms?

First things first, it’s important to explain before going any further answering this question that annelids are earthworms.

Earthworms differ internally from roundworms and flatworms. (Also get to know more differences between earthworms and flatworms).

Another name for earthworms/annelids that describes the differences more clearly is segmented worms.

Segmented worms, or annelids, have the most complex body plans of all invertebrates with worm-like bodies.

These worms have a digestive system, a circulatory system, and a true coelom, with specially designated parts to their body.

In some ways, similar to humans and how our bodies are divided into different sections and areas.

Whereas the other two lack these specific sections.

Flatworms do not have the benefit of a circulatory or respiratory system, neither do they have a coelom.

Similarly, roundworms only have a pseudo coelom.


There we have it, folks.

We are sure you will never look at worms in quite the same way.

At least you now know that there are differences.

Despite all being bilaterally symmetrical and having those winding, thin and long bodies and even though they are all invertebrates, there is more to different worms than meets the eye.

For an interesting point of reference, since we have already highlighted that the most common annelid or segmented worm is the earthworm, You may be interested to know that the tapeworm is the most common type of flatworm, while the Ascaris lumbricodes is the most common roundworm.