Starfish by the starfish in an escape response. The loss of parts of the body is achieved by the rapid softening of a special type of connective tissue in response to nervous signals. This type of tissue is called catch connective tissue and is found in most echinoderms. An autotomy-promoting factor has been identified which, when injected into another starfish, causes rapid shedding of arms. The lifespan of a starfish varies considerably between species, generally being longer in larger forms and in those with planktonic larvae. For example, "Leptasterias hexactis" broods a small number of large-yolked eggs. It has an adult
Starfish a means of defence. The Asteroidea occupy several significant ecological roles. Starfish, such as the ochre sea star ("Pisaster ochraceus") and the reef sea star ("Stichaster australis"), have become widely known as examples of the keystone species concept in ecology. The tropical crown-of-thorns starfish ("Acanthaster planci") is a voracious predator of coral throughout the Indo-Pacific region, and the northern Pacific sea star is considered to be one of the world's 100 worst invasive species. The fossil record for starfish is ancient, dating back to the Ordovician around 450 million years ago, but it is rather sparse, as starfish tend to