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Video showing the tube feet movement of a starfish Close up starfish at Wakatobi National Park, 2018. The scientific name Asteroidea was given to starfish by the French zoologist de Blainville in 1830. [93] It is derived from the Greek aster, ἀστήρ (a star) and the Greek eidos, εἶδος (form, likeness, appearance). [94]
If anything touches its aboral (upper) surface, the starfish reacts by snapping shut the pedicellariae in the vicinity of the stimulus. By this means it can catch prey items such as small fish. [3] The victim is passed to the mouth by movements of the arms and by actions of the tube feet.
A bipinnaria is the first stage in the larval development of most starfish, and is usually followed by a brachiolaria stage. Movement and feeding is accomplished by the bands of cilia. Starfish that brood their young generally lack a bipinnaria stage, with the eggs developing directly into miniature adults.
A starfish has five identical arms with a layer of “tube feet” beneath them that can help the marine creature move along the seafloor, causing naturalists to puzzle over whether sea stars have ...
The starfish body plan consists of five to six arms radiating from a central disk. Regenerative ability differs greatly among starfish species, but can generally be classified within three categories: unidirectional regeneration, disk-dependent bidirectional regeneration, and disk-independent bidirectional regeneration.
The animal then moves in a co-ordinated way, propelled by the other four arms. During locomotion, the propelling arms can made either snake-like or rowing movements. [80] Starfish move using their tube feet, keeping their arms almost still, including in genera like Pycnopodia where the arms are flexible.
Madreporite of Asterias. In sea stars, water enters the system through a sieve-like structure on the upper surface of the animal, called the madreporite.This overlies a small sac, or ampulla, connected to a duct termed the stone canal, which is, as its name implies, commonly lined with calcareous material.
Test starfish were placed in the downstream odour plume, one metre (3 ft 3 in) away from the food source and the movements of each starfish were recorded on videotape. A control was provided using the same flow conditions but without an odour being present. 12 of the test starfish (20%) moved towards the target and got within 15 cm (6 in) of it ...