Echinodermata is a phylum of marineanimals that includes starfish, sea urchins, sand dollars, and sea cucumbers. They are known for their radial symmetry and spiny skin, which is where the name "echinoderm" comes from (echinos meaning "spiny" in Greek).
Characteristics of Echinodermata
Radial symmetry: Echinoderms have a body plan that is symmetric around a central axis, similar to the spokes of a wheel.
Endoskeleton: They possess a calcareous endoskeleton made up of ossicles, or small bony plates, which gives them structural support.
Water vascular system: Echinoderms have a unique hydraulic system consisting of fluid-filled canals and tube feet used for locomotion, feeding, and gas exchange.
Regeneration: Many echinoderms have the ability to regenerate lost body parts, such as arms or spines.
Spiny skin: Their skin is covered in small, calcareous ossicles and spines, providing protection against predators.
Asteroidea (starfish): Characterized by their five arms radiating from a central disc, often found in intertidal zones or shallow waters.
Ophiuroidea (brittle stars): Have long, flexible arms distinct from the central disc, commonly found in both shallow and deep waters.
Echinoidea (sea urchins and sand dollars): Typically have a spherical or flattened body covered in spines, found in a wide range of marinehabitats.
Crinoidea (sea lilies and feather stars): Consist of a cup-shaped body with feathery arms, mainly found in deep-seaenvironments.
Holothuroidea (sea cucumbers): Elongated, soft-bodied animals with a leathery skin, inhabiting various marinehabitats including seafloors and coral reefs.
By understanding the unique characteristics and ecological importance of echinoderms, you can develop a comprehensive understanding of this fascinating group of marineanimals.
Energy - A. Energy is involved in all physical and chemical processes. It is conserved, and can be transformed from one form to another and into work. At the atomic and nuclear levels energy is not continuous but exists in discrete amounts. Energy and mass are related through Einstein's equation E=mc 2 . B. The properties of atomic nuclei are responsible for energy-related phenomena such as radioactivity, fission and fusion. C. Changes in entropy and energy that accompany chemical reactions influence reaction paths. Chemical reactions result in the release or absorption of energy. D. The theory of electromagnetism explains that electricity and magnetism are closely related. Electric charges are the source of electric fields. Moving charges generate magnetic fields. E. Waves are the propagation of a disturbance. They transport energy and momentum but do not transport matter.
Relate temperature to the average molecular kinetic energy.