Difference Between Brachiopod and Bivalve

The key difference between brachiopod and bivalve is that brachiopod belongs to the phylum Brachiopoda while bivalve belongs to the phylum Mollusca.

Brachiopod and bivalve are two different organisms that have a shell with two valves. However, the two valves of the brachiopod shell are unequal in size while the two valves of the bivalve shell are equal in size. Both brachiopods and bivalves are bilaterally symmetrical. Moreover, they are aquatic invertebrates. However, though they look similar in outer appearance, they belong to two different phyla. Brachiopods belong to phylum Brachiopods while bivalves belong to phylum Mollusca.

CONTENTS

1. Overview and Key Difference
2. What is Brachiopod 
3. What is Bivalve
4. Similarities Between Brachiopod and Bivalve
5. Side by Side Comparison – Brachiopod vs Bivalve in Tabular Form
6. Summary

What is Brachiopod?

Brachiopod is an invertebrate that belongs to phylum Brachiopoda. They have a shell with two valves closing each other. Usually, one valve is larger than the other. The larger valve has a hole called pedicle foramen, hence the name pedicle valve. The smaller valve is the brachial valve that contains a brachidium.

Figure 01: Brachiopod

Brachiopods are suspension feeders living only in marine water. There are two major classes of brachiopods as inarticulate brachiopods and articulate brachiopods.

What is Bivalve?

Bivalves are aquatic animals that have two matching valves in their shell. They belong to phylum Mollusca. The two valves fuse with each other by adductor muscles and a ligament.

Figure 02: Bivalve

Bivalves are invertebrates. They live in marine water, fresh water as well as in brackish water. Bivalves include more than 15,000 species of clams, oysters, mussels, scallops, etc.

What are the Similarities Between Brachiopod and Bivalve?

• Brachiopod and bivalve are invertebrates that belong to Kingdom Animalia.
• Both brachiopod and bivalve have adductor muscles.
• They have a shell with two halves.
• Moreover, their shells are made up of calcite.
• Also, they have an epithelial mantle.
• Furthermore, they are bilaterally symmetrical.
• Besides, both brachiopod and bivalve are suspension feeders.

What is the Difference Between Brachiopod and Bivalve?

Brachiopod and bivalve are two invertebrates that have a shell composed of two valves. But, they belong to two different phyla. Brachiopod belongs to phylum Brachiopoda while bivalve belongs to phylum Mollusca. So, this is the key difference between brachiopod and bivalve. Moreover, brachiopod lives only in marine environments while bivalve lives in marine, freshwater and brackish water environments. Therefore, this is also a difference between brachiopod and bivalve.

Moreover, a significant difference between brachiopod and bivalve is their valves. The brachiopod shell has two valves which are unequal in size while the bivalve shell has two valves which are equal in size.

Summary – Brachiopod vs Bivalve

Brachiopod belongs to phylum Brachiopoda. It has a shell with unequal two valves. On the other hand, bivalve belongs to phylum Mollusca and has a shell with equal two valves. Furthermore, brachiopods live only in marine habitats while bivalves live in both marine and freshwater environments. Thus, this summarizes the difference between brachiopod and bivalve.

Reference:

1.“Bivalve.” Bivalve – an Overview | ScienceDirect Topics, Available here.
2. Morton, Brian. “Bivalve.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 18 Mar. 2019, Available here.

Image Courtesy:

1. “Brachiopod fossil” (CC BY 2.5) via Commons Wikimedia
2. “Cockle (bivalve)” By Bernard Spragg. NZ (Public Domain) via Flickr

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