The seashell serves as the outer covering and protection for sea animals in a group known as mollusks. The seashell is the animal's skeleton except it is on the outside of the animal instead of inside the animal like a human's skeleton.
There are thousands of types of mollusks, resulting in thousands of types of shells. These changes are caused by different genetics among species and the different environments in which the mollusks live.
Seashells with holes in them have likely been smashed against a rock as they washed onto the beach, or the creature living in the shell was attacked by a predator. The predator may have chipped away at the shell in an attempt to break it open and eat the creature inside.
According to SeashellWorld.com, the color and the pattern found on a seashell depends on the diet of the creature. A steady diet may cause a spiral pattern where as an inconsistent diet can lead to spots along the shell.
While protection is the primary function, shells do not always serve simply as protection. Certain mollusks use the shell to keep from losing water and drying out while others use the shell to help them move with the currents.
Starfish have no brains and no blood. Their nervous system is spread through their arms and their blood is actually filtered sea water.
When starfish lose an arm, they can grow it back! This process is called "Autotomy." After the arm comes off, the cut area begins to heal and a new arm begins to grow. The arm that is broken off will die. However, in some cases, not only do the starfish grow new arms, but the arms that have been cut off grow new starfish.
There are some 2,000 species of sea star living in all the world's oceans, from tropical habitats to the cold seafloor. The five-arm varieties are the most common, hence their name, but species with 10, 20, and even 40 arms exist.
They have bony, calcified skin, which protects them from most predators, and many wear striking colors that camouflage them or scare off potential attackers. Purely marine animals, there are no freshwater sea stars, and only a few live in brackish water.
Succinea ovalis Say, 1817 taken by Fred Habegger on 6/9/12. He says "Those snails were as populous as I have ever seen them anywhere, on the Cocalico Creek floodplain at Ephrata, even sliding along on top of stinging nettles!"