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Geology F795 > Echinoids > Flashcards

Flashcards in Echinoids Deck (13):

Phylum and class



What are the fetires of skeleton of regular Echinoids

Test made of calcite, interlocking ambulances and interambulacra plates, radiate from top of animal from oral to aboral. Ambulances narrow, perforated with pore pairs, tube feet protrude in life. Interambulacra have tubercles for spine attachment. May be covering of soft tissue


What is the apical system of a regular Echinoid?

Centre it aboral surface, ten plates arranged in rings around anus. Five genital plates, largest in madreporite perforated by pores allowing water o enter vascular system m. Smaller ocular plates, anis surrounded by perioroct membrane
On aboral to allow waste to be carried away by currents


Describe mouth of regular Echinoid

Centre of oral, surrounded by peristome membrane, edge of test turned inwards, to produce perignathic girdle lip, feeding apparatus attached. Five jaws, aristotles lantern. Scrape algae off rocks, on underside for easy feeding


What is the function if tube feet?

Soft tissue that extends from test through pores, for attachment, movement and respiration. Part of water vascular system


What are tubercles for?

Spine attachment, on interambulacra like plates, bass and mamaleon, muscle attached spine to boss, can contact to move spine, used for walking and defence dis articulate after death


What is mode of life of a regular Echinoid?

Live on rocky shores, high energy so eobust, graze in algae in rocks, move along shore using spines Benthonic m, vagrant


What are features of animals in Echinodermata?

Five fold symmetry and tube feet


Describe morphology of irregular Echinoids

Amy's outside apical system, moved towards. Edge. Heart shaped, bilateral symmetry, can live in burrow


How is the mouth positioned on an irregular Echinoid?

Underside, moves to edge, no jaws/girdle, filter feeder, labrum is lip to direct currents and prevent sediments getting in. Plastron, tubercles for spine attachment, used to dig burrow or move within it


How are the ambulacral plates adapted in irregular Echinoids?

Do not extend around whole test, terminate as pet aloud ambulacral if aboral surface, pore pairs for tube feet, at anterior is larger and lined with cilia to create groove That generates currents into mouth. Tube feet long so can extend out of burrow


What is the function of the sub anal fasciole?

Modified are near anus, beating cilia to take away waste particles and direct into sanitary tube, tube feet in posterior used to keep burrow clean


What is the mode of life of an irregular Echinoid?

Live in soft sediment, low energy, burrowers, infaunal, filter feeders small mouth, fasciole a to separate water currents, respites via tube feet out of burrow, shaped to move easily though sediment.