These animals are radially symmetrical -they have no distinct front and back, only a top and a bottom. The 6,000 species are usually found in tide pools along the seashore. The classes are: Asteroidea - starfish such as the Six-rayed Star above (Leptasterias hexactis); Ophiuroidea brittle stars; Echinoidea including sea urchins and sand dollars, Holothuroidea -sea cucumbers; and Crinoidea.
Saturday, May 24, 2008
Spiny-skinned (Echinodermata)
Spiny-skinned (Echinodermata)
These animals are radially symmetrical -they have no distinct front and back, only a top and a bottom. The 6,000 species are usually found in tide pools along the seashore. The classes are: Asteroidea - starfish such as the Six-rayed Star above (Leptasterias hexactis); Ophiuroidea brittle stars; Echinoidea including sea urchins and sand dollars, Holothuroidea -sea cucumbers; and Crinoidea.
Friday, May 23, 2008
Marine Stingers (Cnidaria)
Marine Stingers (Cnidaria)
There are some 9,500 species of these water creatures, which are sometimes called Coelenterates.
These animals are radially symmetrical and have tentacles with stinging cells. The more familiar types include jelly fish, sea anemones (pictured), corals, medusas, and hydras. Other Phyla containing species that may be familiar to the amateur include:
a) Sponges (Porifera, 10,000 species)
b) Segmented Worms (Annelida, 8,800 species including the common earthworm and leeches),
c) Lamp shells (Brachiopoda, 350 species)
d) Comb Jellies (Ctenophora, 90 species)
e) Nematodes (Nematoda, 80,000 species)
f) Horsehair worms (Nematomorpha, 240 species)
Soft Bodies (Mollusca)
Soft Bodies (Mollusca)
Mollusca are so named because of their soft bodies (Greek : mollis - soft). The soft bodies of many of the 110,000. Mollusca species are protected by a hard shell, however. Even those as slugs, still hae vestigial traces of a sheel.
The most common classes are Polyplacophora characterised by a shell composed of 8 overlapping plates. such as the Lined Chitton (Tonicella lineata), Gastropoda commonly known as slug, Bivalvia or Bivalves such Cephalopoda comprising octopus and squid as well as the Nautilus.
Other classes are Monoplacophora, scaphoda (tooth shells)
Joint-Legs (Arthropoda)
Joint-Legs (Arthropoda)
If your animal has jointed legs and no spine, you can find it in the Arthropoda phylum. This includes most, if not all, of the animals we commonly call "bugs' as well as the crustaceans. Scientists have described 500,000 species of arthropods and believe that up to to 10,000.000 species are alive today.
The classes of this phylum include the six legged insects (Insecta), the eight legged Arachnids (Arachnida) including spiders , scorpions and ticks the hard bodied Crustaceans (Crustacea) including crabs, shrimp and barnacies and Malacostraca which includes the sowbug or pillbug.
Other Arthropod classes are Merostomata-home of the Horseshoe crab, Millipedes (Diplopoda) and Centipedes (Chilopoda)
Spinal Cords (Chordata)
Spinal Cords (Chordata)
All animal having a spine, including fish, mammal, birds, reptiles, amphbians, sharks and eels are grouped into Chordata.
Because these animals are so familiar to us, biologists have come up with elaborate classfication sdhemes including subphyla, superclasses, infraorders and the like.
The vast majority (including all the classes listed above) fit into the subphylum Vertebrata thise having a ackbone. Subphyla Agnatha, jawless fish, includes certain eels such as the Lamprey. Cephalochordata and Tunicata round outthe list of subphyla with fairly obscure creatures called Lancelets and Tunicates, repectively.
All told, this familiar phylum includes 45,000 species of wich you are just one.
The Animal Kingdom (ANIMALIA)
The Animal Kingdom is at once the Kingdom most and lest fammiliar to us. Almost all of the animals we commonly think of mammal, fish and birds belong to a single subgroup within one of the 33 Phyla comprising the Animal Kingdom.
On the other hand, over 100,00 species in some 25 animal phyla mostly small worms are so unfamiliar that they are virtually unknown to nonscientists. The same goes for several hundred thousand tiny insect-like species populating the Arthropoda phylum.
All told, around 800,000 species have been identified in the Animal Kingdom most of them in the Arthropoda phylum. In fact, some scientists believe that if we were to indentify all species in the tropical rain forests the ranks of Arthropoda would swell to over 10 million special.
On the other hand, over 100,00 species in some 25 animal phyla mostly small worms are so unfamiliar that they are virtually unknown to nonscientists. The same goes for several hundred thousand tiny insect-like species populating the Arthropoda phylum.
All told, around 800,000 species have been identified in the Animal Kingdom most of them in the Arthropoda phylum. In fact, some scientists believe that if we were to indentify all species in the tropical rain forests the ranks of Arthropoda would swell to over 10 million special.
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