Home Club Details Money Matters Activities Kids' World Money Words Links Parents
  Pelican Pennie Savers Club Spring Edition
Starfish Facts
Maximum Length: 26 cm (radius of the arms).
Appearance: The colour on the upper side can vary greatly. They can be red, yellow, violet, brown or blue.
Depth: 0-200 m.
Environment: Hard and soft bottoms. Can be found in large numbers on mussel and oyster banks.
Classification: Kingdom: Animalia, Phylum: Echinodermata, Class: Asteroidea.

Starfish

Sea stars or starfish are marine invertebrates belonging to phylum Echinodermata, class Asteroidea. The names sea star and starfish are also used for the closely related brittle stars, which make up the class Ophiuroidea. They exhibit a superficially radial symmetry, typically with five or more "arms" which radiate from an indistinct disk (pentaradial symmetry). In fact, their evolutionary ancestors are believed to have had bilateral symmetry, and sea stars do have some remnant of this body structure.

Sea stars do not have movable skeletons, but instead possess a hydraulic water vascular system. The water vascular system has many projections called tube feet, on the ventral face of the sea star's arms, which function in locomotion and feeding.

As these creatures are echinoderms and not actually fish, most marine biologists prefer to replace the term starfish with the less misleading term sea star.

Jellyfish Facts
Number of Species: More than 200
Size: Jellyfish range in size from the tiny thimble jellyfish of the Caribbean to the Arctic lion's mane, which has a bell up to 2.5 m (8 ft) in diameter, and tentacles up to ~60 m (~200 ft) long!
Depth: From sea-level to unknown.
Classification: Kingdom: Animalia, Phylum: Cnidaria, Class: Scyphozoa.

Jellyfish

Jellyfish are marine invertebrates belonging to the Scyphozoa class, and in turn the phylum Cnidaria. The body of an adult jellyfish is composed of a bell-shaped, jellylike substance enclosing its internal structure, from which the creature's tentacles suspend. Each tentacle is covered with stinging cells (cnidocytes) that can stun or kill other animals: most jellyfish use them to secure prey or as a defense mechanism. Others, such as Rhizostomae, do not have tentacles at all.

To compensate for its lack of basic sensory organs and a brain, the jellyfish exploits its nervous system and rhopalia to perceive stimuli, such as light or odor, and orchestrate expedient responses. In its adult form, it is composed of 94-98% water and can be found in every pelagic area of the world.

Most jellyfish are passive drifters that feed on small fish and zooplankton that become caught in their tentacles. Jellyfish have an incomplete digestive system, meaning that the same orifice is used for both food intake and waste expulsion. They are made up of a layer of epidermis, gastrodermis, and a thick jellylike layer called mesoglea that separates the epidermis from the gastrodermis.

Since jellyfish do not biologically qualify as actual "fish", the term "jellyfish" is considered a misnomer by some, who instead employ the names "jellies" or "sea jellies". The name "jellyfish" is also often used to denote either Hydrozoa or the box jellyfish, Cubozoa. Contents

Crab Facts
Maximum Length: 26 cm (radius of the arms).
Appearance: The colour on the upper side can vary greatly. They can be red, yellow, violet, brown or blue.
Depth: 0-200 m.
Environment: Hard and soft bottoms. Can be found in large numbers on mussel and oyster banks.
Classification: Kingdom: Animalia, Phylum: Arthropoda, Subphylum: Crustacea, Class: Malacostraca, Order: Decapoda, Suborder: Pleocyemata, Infraorder: Brachyura

Crabs

The term crab is often applied to several different groups of short (nose to tail) decapod crustaceans with thick exoskeletons, but only members of the Brachyura are true crabs. Other taxa, such as hermit crabs, porcelain crabs and king crabs are, despite superficial similarities, not crabs at all; rather, they belong to the Anomura and can be distinguished from true crabs by counting the legs. In Anomura, the last pair of pereiopods (walking legs) is hidden inside the carapace, so only four pairs are visible (counting the claws), whereas uninjured true crabs always have five visible pairs.

Crabs are crustaceans in the infraorder Brachyura, in the order Decapoda. They have five pairs of walking legs (the first of which is modified into a pair of claws or chelae) and typically a flattened shell. In all but a few crabs (for example, Raninoida), the abdomen is folded under the cephalothorax. The form of the abdomen usually reveals the sex of the crab; males have a narrow abdomen, while females have a much wider abdomen, under which they carry their eggs. Crabs are a very diverse group, mostly found in saltwater, but with some groups living in freshwater or on land. Although famed for their tendency to walk sideways, crabs are in fact able to walk in any direction. Classification within the crabs is traditionally based on the position of the gonopores: whether they are found on the legs or on the thorax. In the two "primitive" sections (sometimes called collectively the "Podotremata"), the gonopores are found on the legs (as in all other decapods); in the Heterotremata, the male gonopores are on the legs, and the female gonopores are on the sternum; in the Thoracotremata, the gonopores are on the sternum in both males and females.

Pelican Pennie Savers Club is Brought to You By
Sun Credit Union


©2002 - 2019 CommonBond Communications, Inc.
Credit Unions Online