Echinoderms

The brittle star has very flexible arms that can brake of in situations involving a predator. The broken arms will continue to wiggle and move to distract said preditor, allowing the brittle star itself to escape.

Appendages.............in multiples of........numbers........and clouds

Echinoderms are invertebrates with an internal skeleton and a system of fluid-filled tubes called a water vascular system. There are four major groups of echinoderms: sea stars, brittle stars, sea urchins, and sea cucumbers.

Echinoderms have swimming larvae that are bilaterally symmetrical, with left and right sides, but they do not 'develop into' bottom-living adult echinoderms, which are radially symmetrical, often star-shaped. The juvenile (young adult), radial from the start, grows from a group of stem cells within the larva. It gradually moves to the outside of the larva, and the larva and juvenile develop side-by-side. In most cases, the larva eventually settles and shrivels, and the juvenile crawls away. In one species of starfish, however, the juvenile drops off the swimming larva, which can go on swimming for a further three months.

they are in the shape of a star

There are many places one can go to purchase starfish pendants. One can first visit their local jewelry stores or the jewelery counter at their local department store such as Sears. Online options would be Amazon or even eBay.

Starfish, or sea stars, play a crucial role in marine ecosystems, primarily as predators that help maintain the balance of species populations on coral reefs and in other habitats. By controlling the abundance of certain prey, such as mollusks, they contribute to the overall health of the ecosystem. However, in some cases, an overpopulation of certain starfish species, like the crown-of-thorns starfish, can lead to coral reef damage, indicating that their impact can be both beneficial and detrimental depending on the context. Overall, their presence is essential for ecological balance in their environments.

When a starfish pries open the shell of a clam or oyster, it uses its tube feet to exert pressure on the shell. The mollusk instinctively tries to close its shell to protect itself, but the starfish can exploit even a slight opening. Once the shell is slightly ajar, the starfish extends its stomach out of its body and into the clam or oyster, secreting enzymes to digest the soft tissue before absorbing the nutrients. This method allows the starfish to feed effectively despite the mollusk's resistance.

Echinoderms, such as starfish and sea urchins, typically inhabit marine environments, particularly in shallow waters along coastlines, coral reefs, and rocky substrates. They can also be found at various depths in the ocean, from tidal pools to deep-sea habitats. Their unique water vascular system allows them to navigate and thrive in diverse marine ecosystems.

In starfish, the cleavage is typically described as irregular or unequal, resulting in blastomeres of varying sizes. This is due to the specific patterns of division that produce larger and smaller cells rather than uniform-sized blastomeres. As a result, the early embryonic development of starfish reflects this uneven distribution in cell sizes, which is characteristic of their specific type of holoblastic cleavage.

their body plan

A clownfish protects itself by living inside poisonous sea anemone. It is unknown how it doesn't get stung. It is inferred that they have a layer of mucus that protects them from the stings.

Their skin is covered with bumpy gills.

• They have radial symmetry
• They have internal calcareous skeleton
• They are often covered with spines (sea urchins, etc)

Yes.

Imagine cutting a starfish or a sand-dollar in half.

It will be symmetrical on both sides, just like a mirror image.

Hope this helps!

:3

sea cucumber

ning

Sea urchins and sand dollars.

Echinoderms live only in the sea.