Bio 2.2 Lab Exam 2: Echinodermata

An animal that during development the blastopore develops into the anus instead of the mouth.

Radial symmetry

Chemoreceptors and eye spots.

No

You must maintain the osmotic concentration of the environment.

• Asteroida
• Ophiuroidea
• Echinoidia
• Holothuroidea
• Crinoidea

Ophiuroidea

Echinoidea

Holothuroidea

Crinoidea

Calcium carbonate plates called dermal ossicles.

Protection

The collagen in its endoskeleton softens, changes shape, and hardens again.

Tiny calcareous pincers around the base of the spines.

The side without the mouth.

Pouches in the coelomic cavity that extend through gaps in the dermal ossicles.

They are the primary respiratory surface and diffuse waste.

Papulae

A white plate on the aboral side of a starfish that serves as an inlet for water.

The side where the mouth is located.

Pyloric cecae (digestive glands) secrete enzymes into pyloric ducts which runs toward the pyloric stomach.

Ampulla

The tops of the tube feet.

It takes water down to the ring canal and out the radial canals that run down each arm.

Lateral canals with one-way valves branching off of the radial canal.

Ampullae have circular muscle around them while the tube feet have longitudinal muscles.

When muscle in the ampullae contract, the tube feet extend outward.

The suction cup on the end of the tube foot attaches to something and the longitudinal muscles contract making a suction.

• A: Spines
• B: Pyloric Cecae (Digestive Glands)
• C: Gonads
• D: Radial Canal
• E: Ampullae
• F: Mouth

• A: Madreporite
• B: Pyloric Stomach