What is the Difference Between Mollusks and Arthropods?

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Mollusks and arthropods are both large and diverse groups of invertebrate animals. They share some similarities, such as bilateral symmetry, but there are several key differences between them:

  1. Body Structure: Mollusks have soft bodies, usually covered in mucus, while arthropods have segmented bodies with paired appendages or legs.
  2. Exoskeleton: Arthropods have an exoskeleton made of chitin, which covers their body. Mollusks, on the other hand, have shells surrounding their soft bodies.
  3. Locomotion: Mollusks use a muscular foot for movement, which can be modified into arms or tentacles in some species. Arthropods, such as insects, have wings to fly.
  4. Respiration: Mollusks generally breathe through gills or lungs. Arthropods have various respiratory systems depending on their habitat and group, such as trachea, book gills, or lungs.
  5. Reproduction: Mollusks reproduce sexually, even in hermaphroditic forms, and go through a free-swimming larval stage called the trochophore. Arthropods also reproduce sexually, but their reproductive systems vary depending on the group.

Examples of mollusks include snails, clams, and squids, while arthropods include spiders, mites, insects, crustaceans, and other segmented animals.

Comparative Table: Mollusks vs Arthropods

Mollusks and arthropods are both invertebrate phyla with great diversity in the animal kingdom. They possess bilateral symmetry, meaning their bodies are divided into two equal halves. However, they have several differences in their body structure and other features. Here is a table comparing the differences between mollusks and arthropods:

Feature Mollusks Arthropods
Body Structure Soft-bodied with an internal or external shell Segmented bodies with paired appendages and exoskeleton
Exoskeleton Not present Present, made of chitin
Body Covering Mantle, a thin layer of tissue covering internal organs Exoskeleton, which restricts growth and is molted regularly
Appendages None Paired jointed appendages
Examples Snails, clams, squids Spiders, scorpions, shrimps, mites, crabs, lobsters, insects

Mollusks have a soft body and are usually covered in mucus, while arthropods have a segmented body with paired appendages and an exoskeleton. Mollusks include species like snails, clams, and squids, while arthropods include spiders, scorpions, shrimps, mites, crabs, lobsters, and insects.