Instruct: Given a question, retrieve relevant passages that answer the question.
Query: How do starfishes eat?
Starfish are marine invertebrates. They typically have a central disc and five arms, though some species have a larger number of arms. The aboral or upper surface may be smooth, granular or spiny, and is covered with overlapping plates. Many species are brightly coloured in various shades of red or orange, while others are blue, grey or brown. Starfish have tube feet operated by a hydraulic system and a mouth at the centre of the oral or lower surface. They are opportunistic feeders and are mostly predators on benthic invertebrates. Several species have specialized feeding behaviours including eversion of their stomachs and suspension feeding. They have complex life cycles and can reproduce both sexually and asexually. Most can regenerate damaged parts or lost arms and they can shed arms as 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 common starfish feeds on a variety of benthic organisms. These include bivalve molluscs, polychaete worms, barnacles, gastropod molluscs, other echinoderms and carrion. When feeding on a mollusc such as a mussel, it attaches its tube feet to each shell valve and exerts force to separate them slightly. Even a gap of only is sufficient for the starfish to insert a fold of its stomach, secrete enzymes and start digesting the mollusc body. When the contents is sufficiently liquid, it brings its stomach back to its rightful position with the food inside. The common starfish has a well-developed sense of smell and can detect the odour of prey species such as the common mussel ("Mytilus edulis") and crawl towards it. It can also detect the odour of the predatory common sunstar ("Crossaster papposus"), which eats other starfish, and take evasive action.
The common starfish is dioecious, which means that each individual is either male or female. In the spring, the females release their eggs into the sea. A moderate sized starfish is estimated to be able to produce 2.5 million eggs. The males shed their sperm and fertilisation takes place in the water column. The larvae are planktonic and drift for about 87 days before settling on the seabed and undergoing metamorphosis into juveniles. Common starfish are believed to live for about seven to eight years. When well fed, the juveniles can increase their radius at the rate of slightly more than per month during the summer and autumn and slightly less than per month in the winter. An adult common starfish can survive starvation for several months although it loses weight in the process. One specimen shrank from a radius of to a radius of after starvation for five months.
Some starfish evert their stomachs through their mouths to eat their prey. The starfish then retracts its stomach back inside of its body.
Atlantic wolffish use their strong jaws to eat hardshell molluscs, crustaceans, and echinoderms. They do not eat other fish. They are known to frequently eat large whelks ("Buccinum"), cockles ("Polynices", "Chrysodomus" and "Sipho"), sea clams ("Mactra"), large hermit crabs, starfish, sea urchins. They are an important predator of sea urchins and green crabs, whose populations escalate rapidly and can negatively affect the health of a marine system.
"Odontaster validus" does not attack members of its own species but can attack starfish of other species. This seems to be due to chemoreceptors which can identify conspecifics by their odour. Starfish often converge on food sources and a study was undertaken to examine how they do this. It was found that food-deprived individual "Odontaster validus" could distinguish between the odours emitted by satiated and by starved starfish of the same species. They were strongly attracted to the former and took little notice of the latter.
He is co-author of the best-selling book "The Starfish And the Spider", which lays out a new organizational theory for considering all organizations as existing on a continuum between centralized to decentralized, with different implications and strategies for each firm based upon their position on that axis. In interviews with "The Washington Post" and "USA Today", Beckstrom explains how, using the 'Starfish' concept illustrated in "The Starfish And the Spider", the U.S. Government can take a different approach in their dealings with Al-Qaeda. Beckstrom is also the formulator of an economic model for valuing networks, Beckstrom's law, which was presented at BlackHat 2009 and Defcon 2009.
Campaigns and Community Support
The supporter base of Starfish Greathearts Foundation is based on widespread support from individuals through donations and income generated through successful campaigns. The Dinners of Hope Campaign is the most popular ongoing campaign that Starfish has developed. It is simple in the fact that everyone has to eat and therefore everyone can participate in the campaign. The emphasis of this campaign brings to the table the chance to educate, communicate and fundraise with minimal input and optimal results. The concept is simple in that supporters are asked to host a meal for family, friends or colleagues and then ask guests for a doantion rather than a contribution to the meal. The campaign also works as a powerful tool in promoting HIV/AIDS awareness and education at all levels. The campaign has mobilised more than 20,000 individuals and 120 corporations worldwide to participate.
Since 2010, the Marine National Park Headquarters and some other organizations have inspected the coral reefs and removed crown-of-thorns starfish, which eat coral. No large populations of crown-of-thorns starfish were found in 2014 and 2015. It is unclear if this was caused by the removal of the crown-of-thorns starfish or the life cycle of the starfish.
A species of pufferfish and two triggerfish have been observed to feed on crown-of-thorns starfish in the Red Sea, and, although they may have some effect on the A. planci population, no evidence exists of systematic predation.[31] In the indo-pacific waters, white-spotted puffers, and Titan triggerfish have also been found to eat COTS[32] The Triton's trumpet, a very large gastropod mollusc, is a known predator of Acanthaster in some parts of the starfish's range. The triton has been described as tearing the starfish to pieces with its file-like radula.[33] The small painted shrimp Hymenocera picta, a general predator of starfish, has been found to prey on A. planci at some locations.[34] A polychaete worm, Pherecardia striata, was observed to be feeding on the starfish together with the shrimp on an east Pacific coral reef.[35] About 0.6% of the starfish in the reef population were being attacked by both the shrimp and polychaete worm, killing the starfish in about a week. Glynn suggested this resulted in a balance between mortality and recruitment in this population, leading to a relatively stable population of starfish.[34] Since P. striata can only attack a damaged A. planci and cause its death, it may be regarded as an 'impatient scavenger' rather than a predator.[36] As distinct from predators, dead and mutilated adults of A. planci attract a number of scavengers. Glynn lists two polychaete worms, a hermit crab, a sea urchin, and seven species of small reef fish.[35] Apparently, they are able to tolerate the distasteful saponins for an easy meal. A large polyp-like creature of the cnidarian genus Pseudocorynactis was observed attacking, and then wholly ingesting a crown-of-thorns starfish of similar size.[37] Continued studies revealed this polyp is able to completely ingest a crown-of-thorns specimen of up to 34cm (13in) in diameter.[38]
An aboriginal Australian fable retold by the Welsh school headmaster William Jenkyn Thomas (1870–1959)[124] tells how some animals needed a canoe to cross the ocean. Whale had one but refused to lend it, so Starfish kept him busy, telling him stories and grooming him to remove parasites, while the others stole the canoe. When Whale realized the trick he beat Starfish ragged, which is how Starfish still is today.[125]
During the breeding season, which is typically during early to midsummer, the starfish may gather together high on a reef and synchronously release gametes to achieve high levels of egg fertilisation.[27] This pattern of synchronised spawning is not at all unique, but it is very common amongst marine invertebrates that do not copulate. Solitary spawning gives no opportunity for fertilisation of eggs and wastes gametes and evidence exists of a spawning pheromone that causes the starfish to aggregate and release gametes synchronously.[28] When the starfish are at high densities, they may move day and night, competing for living coral.
Crown-of-thorns starfish ("Acanthaster planci") is the major predator of the reefs, as it preys upon coral polyps by climbing onto them, extruding its stomach over them, and releasing digestive enzymes to absorb the liquefied tissue. An individual adult can eat up to 6 m of reef per year. In 2000, an outbreak of crown-of-thorns starfish contributed to a loss of 66% of live coral cover on sampled reefs. Changes in water quality and overfishing of natural predators, such as the Giant Triton, may have contributed to an increase in the number of crown-of-thorns starfish.
Harlequin shrimp's only source of nutrition comes from starfish. They are very skilled at flipping over the slow starfish on its back, and eating the tube feet and soft tissues until it reaches the central disk. They, usually one female and one male, use their claws to pierce the tough skin and feeding legs to help them maneuver the starfish. Sometimes the starfish will shed the arm that the shrimp attacked and regrow (the shrimp can then re eat it), but it is usually too wounded to regrow. They may also feed on sea urchins, because they have tube feet as well, but that is rare and only if they're very hungry.
Overfishing, particularly selective overfishing, can unbalance coral ecosystems by encouraging the excessive growth of coral predators. Predators that eat living coral, such as the crown-of-thorns starfish, are called "corallivores". Coral reefs are built from stony coral, which evolved with large amounts of the wax cetyl palmitate in their tissues. Most predators find this wax indigestible. The crown-of-thorns starfish is a large (up to one meter) starfish protected by long, venomous spines. Its enzyme system dissolves the wax in stony corals, and allows the starfish to feed on the living animal. Starfish face predators of their own, such as the giant triton sea snail. However, the giant triton is valued for its shell and has been over fished. As a result, crown-of-thorns starfish populations can periodically grow unchecked, devastating reefs.
Adult tritons are active predators and feed on other molluscs and starfish. The giant triton has gained fame for its ability to capture and eat crown-of-thorns starfish, a large species (up to 1 m in diameter) covered in venomous spikes an inch long. The crown-of-thorns starfish has few other natural predators and has earned the enmity of humans in recent decades by proliferating and destroying large sections of coral reef, turning them into coral skeletons, empty husks of calcium carbonate.
Tritons can be observed to turn and give chase when the scent of prey is detected. Some starfish (including the crown-of-thorns starfish) appear to be able to detect the approach of the mollusc by means which are not clearly understood, and they will attempt flight before any physical contact has taken place. Tritons, however, are faster than starfish, and only large starfish have a reasonable hope of escape, and then only by abandoning whichever limb the snail seizes first.
After settling into a home, the larva changes into a juvenile sea star. This process takes about 2 days. Initially the juvenile starfish has only 5 arms but additional arms develop rapidly as the starfish begins to feed on encrusting algae. At the end of 6 months the starfish is about 1 cm in size and begins to feed on corals. The starfish becomes sexually mature at the end of its second year by which time it has grown to about 20 cm in diameter. After 3–4 years (when the starfish is about 35 cm in size) it is thought to go into a senile phase where growth declines dramatically and reproduction is low. This phase has been identified only in the laboratory. It is not known how long starfish live however, they have been kept in aquaria for as long as 8 years.
Prey of cnidarians ranges from plankton to animals several times larger than themselves. Some cnidarians are parasites, mainly on jellyfish but a few are major pests of fish. Others obtain most of their nourishment from endosymbiotic algae or dissolved nutrients. Predators of cnidarians include: sea slugs, which can incorporate nematocysts into their own bodies for self-defense; starfish, notably the crown of thorns starfish, which can devastate corals; butterfly fish and parrot fish, which eat corals; and marine turtles, which eat jellyfish. Some sea anemones and jellyfish have a symbiotic relationship with some fish; for example clown fish live among the tentacles of sea anemones, and each partner protects the other against predators.
Each starfish arm contains two gonads that release gametes through openings called gonoducts, located on the central disc between the arms. Fertilization is generally external but in a few species, internal fertilization takes place. In most species, the buoyant eggs and sperm are simply released into the water (free spawning) and the resulting embryos and larvae live as part of the plankton. In others, the eggs may be stuck to the undersides of rocks.[31] In certain species of starfish, the females brood their eggs – either by simply enveloping them[31] or by holding them in specialised structures. Brooding may be done in pockets on the starfish's aboral surface,[32][33] inside the pyloric stomach (Leptasterias tenera)[34] or even in the interior of the gonads themselves.[29] Those starfish that brood their eggs by "sitting" on them usually assume a humped posture with their discs raised off the substrate.[35] Pteraster militaris broods a few of its young and disperses the remaining eggs, that are too numerous to fit into its pouch.[32] In these brooding species, the eggs are relatively large, and supplied with yolk, and they generally develop directly into miniature starfish without an intervening larval stage.[29] The developing young are called lecithotrophic because they obtain their nutrition from the yolk as opposed to "planktotrophic" larvae that feed in the water column. In Parvulastra parvivipara, an intragonadal brooder, the young starfish obtain nutrients by eating other eggs and embryos in the brood pouch.[36] Brooding is especially common in polar and deep-sea species that live in environments unfavourable for larval development[33] and in smaller species that produce just a few eggs.[37][38]
Some species of starfish are able to reproduce asexually as adults either by fission of their central discs[45] or by autotomy of one or more of their arms. Which of these processes occurs depends on the genus. Among starfish that are able to regenerate their whole body from a single arm, some can do so even from fragments just 1cm (0.4in) long.[46] Single arms that regenerate a whole individual are called comet forms. The division of the starfish, either across its disc or at the base of the arm, is usually accompanied by a weakness in the structure that provides a fracture zone.[47]
Starfish do not appear to have any mechanisms for osmoregulation, and keep their body fluids at the same salt concentration as the surrounding water. Although some species can tolerate relatively low salinity, the lack of an osmoregulation system probably explains why starfish are not found in fresh water or even in many estuarine environments.[21]
The Crown-of-Thorns Starfish is a coral reef predator which preys on coral polyps by climbing onto them, extruding its stomach over them, and releasing digestive enzymes to absorb the liquefied tissue. An individual adult of this species can eat up to six square meters of living reef in a single year. Geological evidence suggests that the Crown-of-Thorns Starfish has been part of the Great Barrier Reef's ecology for "at least several thousand years", but there is no geological evidence for Crown of Thorns outbreaks. The first known outbreak occurred during the 1960s. Large outbreaks of these starfish can devastate reefs. In 2000, an outbreak contributed to a loss of 66% of live coral cover on sampled reefs in a study by the CRC Reefs Research Centre. Although large outbreaks of these starfish are believed to occur in natural cycles, human activity in and around the Great Barrier Reef can worsen the effects. Reduction of water quality associated with agriculture can cause the crown-of-thorns starfish larvae to thrive. Fertilizer runoff from farming increases the amount of phytoplankton available for the Crown of Thorns Starfish larvae to consume. A study by the Australian Institute of Marine Science showed that a doubling of the chlorophyll in the water leads to a tenfold increase in the crown-of-thorns starfish larvae's survival rate. Overfishing of its natural predators, such as the Giant Triton, is also considered to contribute to an increase in the number of Crown of Thorns Starfish. The CRC Reef Research Centre defines an outbreak as when there are more than 30 adult starfish in an area of one hectare. There have been three large outbreaks of COTS on the reef since observation began, between 1962 and 1976; 1978 and 1991; 1993 and 2005, and a fourth began in 2009. Investigation is being undertaken into mimicking a chemical scent released by the COTS' natural predator, the giant triton snail.
The starfishes "Acodontaster conspicuus", "Acodontaster hodgsoni", "Odontaster meridionalis" and "Perknaster fuscus" feed on the sponges, while "Odontaster validus" mostly scavenges, and "D. brucei" and the gastropod "Trophonella longstaffi" both feed on the bivalve "L. hodgsoni". "D. brucei" primarily feeds on molluscs, but does not seem to eat sponges as do many other starfish. It is sometimes preyed on by the sea anemone "Urticinopsis antarctica". Developing embryos of this species are brooded by the female until they have developed into juvenile starfish.
Reefs are affected by severe weather events, such as cyclones, from predation by crown of thorns starfish and from competition for habitat with other foundation species such as seaweed. Seaweed can take over coral habitat when the water contains excess nutrients (nitrogen and phosphorus) or when fishing stocks are too low and herbivorous fish do not keep the seaweed at bay by eating it. 
After the credits, Big Bird pretends to be a statue. He encourages the viewers to visit their local museum, and comments on how staying perfectly still is tiring and wonders how statues can do it.The title song from "Don't Eat the Pictures" begins with Cookie Monster and his human friend, Bob McGrath in front of "Still Life with Ham", a painting by Philippe Rousseau which Cookie Monster tries to devour. Bob holds Cookie Monster back and reminds him that he promised not to eat anything in the museum. Then Cookie Monster breaks into song, with angelic choral accompaniment, about paintings, statues, and mummies, and how he understands how important it is to not devour them.
Eating disorders are also symbolic with the sociology of food. They represent how control (or lack thereof) someone can have over themselves about one of the things they need to live. Eating disorders do not limit themselves to anorexia. These disorders include bulimia and binge eating as well. Some people often use food a comfort, or even a reward. Or in other cases they see food as a negative thing to avoid, even though they need it for survival. The relationships with food that people carry is a very large subject that is very complex. From a sociological standpoint, media has a lot to do with this. Not only does this have to with the sociology of food, but it has to do with how the media represents society as a whole. Both men and women, but majority women, see the representation on the media, leading them to wanting to feel attractive. A lot of the time, this comes down the person’s relationship with food. When someone has a disorder like anorexia nervousa or bulimia, they have an intense fear of gaining weight, or just the “fatness” they feel they would get by consuming food. With bulimia, the fear is there, with the overcoming urge to binge. These disorders display the psychological relationships that people could have with food, and view it as a negative thing. They focus on the material look of themselves as opposed to needing food for energy and nourishment. This has a lot to do with overwhelming sexuality in the media. Girls, young women, and even men see how they “should” look according to the media, making them turn to desperate measures with these eating disorders.