Crinoid Flashcards 0.0 / 5 ? GeologyMorphology of fossilsA2/A-levelOCR Created by: hollywoodthingsCreated on: 19-05-15 21:54 Phylum Echinodermata 1 of 20 Class Crinoidea 2 of 20 Water vascular system Hydraulic system that allows the animal to extend its tube feet by forcing water into its tissues. 3 of 20 5-fold symmetry 5 planes of symmetry, each giving a mirror image. These form a radial pattern. 4 of 20 Test Made of Calcareous plates 5 of 20 Radial Plates On Calyx- point of attachment for arms. 6 of 20 Basal Plates On Calyx- structural 7 of 20 Infrabasal Plates On Calyx- attach Calyx to stem 8 of 20 Evolution first evolved in Ordovician. Peaked in Upper Paleozoic(early Carboniferous). Are extant. 9 of 20 Environment Moderate energy(filter feeders) Above and below photic zone. 10 of 20 Mode of Life Either sessile(stemmed, Holdfast attached to seabed) or nektonic. Fossil Crinoids mostly stemmed, attached. Presently found at all water depths. 11 of 20 Brachia Delicate structures that waft in currents and use cilia to collect food particles. flexible arms. 12 of 20 Calyx Main part of Crinoid which houses soft tissue. Cup made up of calcareous plates(Infrabasal, Basal, Radial) showing 5-fold symmetry. 13 of 20 Stem Made of calcite plates(Ossicles) with centres linked together with soft tissue. 14 of 20 Holdfast Attaches to substrate On hard substrate secretes cement to attach at base of stem. 15 of 20 Anal Tube Protrudes from centre of Calyx. Gets rid of waste without it mixing with fresh water. 16 of 20 Membrane Soft tissue covering animal to protect calcite. Flexible, decays on death (Crinoid becomes disarticulated) 17 of 20 Feeding Pinnules of Brachia catch food particles which get passed down food grooves by cilia into mouth. 18 of 20 Tegmen For feeding. On top of Calyx and hosts mouth in centre. 5 radial food grooves and anus on side. 19 of 20 Ossicle Calcite plate making up part of the stem. 20 of 20
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