Arthropods: Characteristics and Anatomy

Arthropods Characteristics

• Arthropods have no bones inside; instead, they have a solid shell on the outside for protection.
• The shell, also known as a carapace, is like armor that protects arthropods.
• As arthropods grow, their shell becomes small, and they need to shed it and grow a new one, a process called "shedding".

Arthropod Legs

• Arthropod legs consist of segments, with joints between them, which allow for bending and unbending.
• The segments are the spaces between the joints that don't bend.

Types of Arthropods

Crabs

• Crabs are poor swimmers but can run quickly along the bottom of the sea or shore using their strong legs.

Hermit Lobster

• Hermit lobsters don't float and walk slowly, as they crawl into empty shells and use them as protection.
• The shell protects them from predators.

Shrimp

• Shrimp are poor runners but swim well, with a body like a boat with many oars on both sides.

Daphnia

• Daphnia swim using their branchy antennas, which they use to row.
• Daphnia are a food source for larger aquatic animals.
• They are tiny, with a height of about 1 millimeter, and 10 Daphnia can fit on a single notebook cell.

Crayfish

• Crayfish can run along the bottom and swim, but they run worse than crabs and swim worse than shrimp.