::Characteristics::
Largest phylum to lack any freshwater or land representatives
Many echinoderms form “Tube Feet," which they can move or grip things with
Possess 5-rayed symmetry, mostly radial, sometimes bilateral.
Body has more than two cell layers, tissues and organs.
Body cavity a true coelom.
Most possesses a gut with an anus.
Body shape highly variable, but with no head.
Nervous system includes a circum-oesophageal ring.
Has a poorly defined open circulatory system.
Possesses a water vascular system, which hydraulically operates the tube feet or feeding tentacles.
Without excretory organs.
Normally possesses a sub-epidermal system of calcareous plates
Reproduction normally sexual and gonochoristic.
Feeds on fine particles in the water, detritus or other animals.
All live marine environments
Many echinoderms form “Tube Feet," which they can move or grip things with
Possess 5-rayed symmetry, mostly radial, sometimes bilateral.
Body has more than two cell layers, tissues and organs.
Body cavity a true coelom.
Most possesses a gut with an anus.
Body shape highly variable, but with no head.
Nervous system includes a circum-oesophageal ring.
Has a poorly defined open circulatory system.
Possesses a water vascular system, which hydraulically operates the tube feet or feeding tentacles.
Without excretory organs.
Normally possesses a sub-epidermal system of calcareous plates
Reproduction normally sexual and gonochoristic.
Feeds on fine particles in the water, detritus or other animals.
All live marine environments
::Taxonomy::
Domain: Eukarya
Kingdom: Animalia
Phylum: Echinodermata
Class: Ophiuroidea
Order: Ophiuroida
Family: Ophiodermatidae
Genus: Ophiothrix
Species: spiculata
Kingdom: Animalia
Phylum: Echinodermata
Class: Ophiuroidea
Order: Ophiuroida
Family: Ophiodermatidae
Genus: Ophiothrix
Species: spiculata
::Origin and Natural History of the Animal::
Drawing of a basic cladogram for brittle star
Common Name and "meaning":
-Brittle Stars are very fragile and can cast off one or more arms if disturbed or caught by a predator. These breaks can occur anywhere beyond the disc and the lost portions can be regenerated.
Realistic Cladogram of animal:
*Picture to the left*
-Shows how brittle stars evolved to become stars, yet not fully develop into a thicker star.
The picture below shows how the brittle star (found in Echinodermata) came to be compared to other ancestors.
-A cladogram of phylums based mainly on molecular data. They are divided into three main groups:
-duetersomes, lophotrochozoans, and ecdysozoans.
-Brittle Stars are very fragile and can cast off one or more arms if disturbed or caught by a predator. These breaks can occur anywhere beyond the disc and the lost portions can be regenerated.
Realistic Cladogram of animal:
*Picture to the left*
-Shows how brittle stars evolved to become stars, yet not fully develop into a thicker star.
The picture below shows how the brittle star (found in Echinodermata) came to be compared to other ancestors.
-A cladogram of phylums based mainly on molecular data. They are divided into three main groups:
-duetersomes, lophotrochozoans, and ecdysozoans.
::External Description::
Size: Central disc of the body of most species ranges from 1-3 centimeters or up to 1 inch in diameter (not including legs)
Symmetry: Radical Symmetry, but have bilateral symmetry as a larvae
Color: Blue to Gray; most common is brown; dark brown in daytime and gray at night
Body Covering (skin): Covered in spines for protection
Eyes/Visual: Coated with an all-seeing eye
Nostrils: They have no noses, yet the males are known to detect the "perfume" or phermones of the females
Ears: They have no ears to detect sound so they must depend on what they feel around them
Symmetry: Radical Symmetry, but have bilateral symmetry as a larvae
Color: Blue to Gray; most common is brown; dark brown in daytime and gray at night
Body Covering (skin): Covered in spines for protection
Eyes/Visual: Coated with an all-seeing eye
Nostrils: They have no noses, yet the males are known to detect the "perfume" or phermones of the females
Ears: They have no ears to detect sound so they must depend on what they feel around them