Zoology Assessment by Maddie Davis

Phylum Asteroidea (Sea stars)

25mdavis2_1 — 2024-01-18 21:14:54 UTC

There are about 2,000 species, and their body plan is radial symmetry. They primarily prey on mollusks and they pry them open using their suction-cupped feet. They live up to 35 years. To defend themselves, some have chemical-based toxins such as slime while others just have spines. One unique trait is that they can regenerate.

Phylum Echinoidea (Sea urchins and sand dollars)

25mdavis2_1 — 2024-01-18 21:15:32 UTC

There are about 400 species still alive today. They have a spherical body plan. They prey primarily on plankton, sponges, and mussels. They move over their food and that's how they eat them. They live up to 200 years. They defend themselves by using their tube feet and spines to move away from predators. One unique trait is that the color depends on the species.

Phylum Ophiuroidia (Brittle stars and basket stars)

25mdavis2_1 — 2024-01-18 21:15:44 UTC

There are about 2000 species, they have a round central body disk that carries 5 or 6 or even 7 arms that move like snacks. They are omnivores and feed on detritus and small organisms such as plankton. They defend themselves by self-amputating their arms. This is called autonomy. They live about 5 years. Something unique about them is that they can actual move rather rapidly.

Phylum Crinoidea (Feather stars and sea lilies)

25mdavis2_1 — 2024-01-18 21:16:05 UTC

There are about 550 species of them. They have a cup shaped body and calcite plates in their skin that are rough to touch. They feed on drifting microorganisms; they use their grasping legs to get the food. They live up to 35 years. One unique trait is that they eat with their feet!

Phylum Holothuroidea (Sea cucumbers)

25mdavis2_1 — 2024-01-18 21:16:14 UTC

There are about 1,250 species. They have a radial body plan. They eat basically the same thing as the other phylum's, algae, bacteria, etc. They eat using something called filter feeding, they filter food through their filtering structures. They live about 5-10 years. Something unique about them is they have leathery skin.