Echinodermata Flashcards
What is the ecological or economical importance of echinodermata?
They have a keystone species, they reduce algal mats, they are a delicacy for some and are a source of lime.
What are som characteristics of echinoderms body plans?
They are triploblastic deuterostomes, they are eucoelomates and are radial symmetric as adults. They are dioecious organisms and they have an active lifestyle (but may move very slowly).
What do echinoderms usually have? (referring to the outside of body)
Calcareous, spiny endoskeleton. Covered by ectoderm. Have plates called “ossicles”
How do echinoderms move?
They use a water vascular system. This system has tube feet which are used for movement. They move by alternately contracting muscles that force water into the tube feet, causing them to extend and push against the ground, then relaxing to allow the feet to retract. The tube feet lie on ambulacra.
What are the components of the water vascular system and what do they do?
Tube feet, madreporite, canals and ambulacra. The madreporite is where water enters the system and flows through canals to the tube feet which are used for locomotion. The tube feet are on the part of the body called ambulacra.
How do echinoderms respire and eliminate waste?
Dermal branchial which are tube like projections that allow gas exchange through simple diffusion. These also eliminate waste
What are pedicellariae and what do they do?
They are small claw like projections that have moveable jaws on the outside of the animal and they are used for defense, gathering food or movement depending on the animal.
Describe the nervous system of the echinoderms
They do not have a brain or ganglia, they do have a nerve net. They have a nerve ring and five radial nerves.
What are the characteristics of echinoderms
They are dioecious and have external fertilization. They have indirect development and some even do brooding.
What are the 5 classes of echinoderms we cover?
Asteroidea, Holothuroidea, Ophiuroidea, Crinoidea, and Echinoidea
