Echinodermata

List the 5 main characteristics observed within the phylum Echinodermata

-Spiny Skin -An internal skeleton -Pentradial: 5 way symmetry -A water vascular system -Tube feet

explain/define two common characteristics of all echinoderms

First, they all possess five-part radial symmetry around a central disk. Second, they all possess a very unique water vascular system (vascular system based on water). These unique characteristics distinguish echinoderms from other animals in the animal kingdom.

How does the function of this water vascular system in sea stars differ from sea cucumbers

For cucumbers, this water vascular system allows them to suck in water to fill them up. And with that, they can get hard so predators can't bite them. For starfish they use the system to fill up their tube feet, move around, eat, and more!

3 ways in which brittle stars differ from sea stars

Sea stars are in the class Asteroidea, where brittle stars are in Ophiuroidea. Sea stars have thicker, triangular-shaped arms. Brittle stars, on the other hand, have much thinner arms. The water vascular system includes a number of small tube feet that become stiff when water is pushed into them, allowing the sea star to move on a conveyor belt-like rotation of feet. Although brittle stars also have a water vascular system, they twist and bend their long arms to move, instead. In sea stars, the madreporite is located on the "top" (or aboral, meaning the opposite of the side of the mouth). In brittle stars, it's located on the "bottom" (or oral side).

for each class give one unique characteristics and one species examples

-Asteroid (sea star) : thick arms that extend from a central disk where organs penetrate into the arms -Ophiuroidea (brittle star) : thin arms that are sharply demarcated from the central disk -Echinoidea (sea urchins and sand dollars) : do not have arms, but are hemispherical or flattened with five rows of tube feet that help them in slow movement -Crinoidea (sea lillies or feather stars) : They live both in shallow water and in depths as great as 6,000 meters. Holothuroidea (sea cucumbers) : demonstrate "functional" bilateral symmetry as adults because the uniquely-extended oral-aboral axis compels the animal to lie horizontally rather than stand vertically.

sea cucumbers have two unique defense mechanisms.. describe/draw them

-The tubed feet of some echinoderms can release toxins and the sea cucumber can discharge sticky, entangling threads in which predators can become trapped. -Another defense mechanism of some sea cucumbers is the act of expelling all their internal organs via their anus to either satisfy or confuse their predator.

How does the water move through the water vascular system

-Water enters through the madreporite and flows through a tube, called the stone canal, that connects to the circular ring canal surrounding the mouth. From there, water can flow into five radial canals that branch off the circular ring.

Describe the locomotion of echinoderms. Reference specific body parts in their anatomy that aid in this process.

Echinoderms primarily use their tube feet to move about but some sea urchins also use their spines. ... Waves of tube feet contractions and relaxations move along the adherent surface and the animal moves slowly along.

What happens when you cut an arm off a sea star still containing a portion of the central disk

If a sea star gets an arm gets cut off then they can regenerate the separate arm. If the separate arm carries a portion of the central disk it can create a whole new sea star.

describe how sea stars reproduce

Sexually: Fertilization occurs in the water with males and females releasing sperm and eggs into the environment. Asexually: Takes place by fission or through autotomy of arms. In fission, the central disc breaks into two pieces and each portion then regenerates the missing parts.

Name and describe the specialized mouth structure found on species in the Echinoidea class. During dissections, we observed this specialized structure in which organisms

The mouth, in the peristomal membrane, contains a powerful chewing apparatus called the Aristotle's lantern. The lantern is composed of five jaws and is capable of extending through the mouth of some urchins.

describe the function of aristotles lantern. give two examples of species that contain this structure

The mouth, on the underside of the body, has a complex dental apparatus called Aristotle's lantern, which also may be venomous. The teeth of Aristotle's lantern are typically extruded to scrape algae and other food from rocks, and some urchins can excavate hiding places in coral or rock. Sea urchins.

How do sea stars consume their prey?

The sea star eats by attaching to prey and extending its stomach out through its mouth. Enzymes from the sea star's stomach digest the prey. The digested material enters the sea star's stomach. Tiny organisms can be swallowed whole.