Prey

Prey	Music Home >> Music Genres >> Undetermined Music



< < < < < > > > > > More Info on Prey Similar Undetermined Music Search Artistopia

Biography

In ecology , predation describes a biological interaction where a predator (an organism that is hunting) feeds on its prey (the organism that is attacked).Begon, M., Townsend, C., Harper, J. (1996). Ecology: Individuals, populations and communities (Third edition). Blackwell Science, London. ISBN 0-86542-845-X, ISBN 0-632-03801-2, ISBN 0-632-04393-8. Predators may or may not kill their prey prior to feeding on them, but the act of predation often results in the death of its prey and the eventual absorption of the prey's tissue through consumption. Other categories of heterotroph|consumption are herbivory (eating parts of plants) and detritivore|detritivory , the consumption of dead organic material ( detritus ). All these consumption categories fall under the rubric of consumer-resource systems .Getz, W. (2011). Biomass transformation webs provide a unified approach to consumer–resource modelling. Ecology Letters,doi: 10.1111/j.1461-0248.2010.01566.x. It can often be difficult to separate various types of List of feeding behaviours|feeding behaviors . For example, some parasitic species prey on a host organism and then lay their eggs on it for their offspring to feed on it while it continues to live or on its decaying corpse after it has died. The key characteristic of predation however is the predator's direct impact on the prey population. On the other hand, detritivores simply eat dead organic material arising from the decay of dead individuals and have no direct impact on the "donor" organism(s).

Selective pressure s imposed on one another often leads to an evolutionary arms race between prey and predator, resulting in various antipredator adaptation s. Ways of classifying predation surveyed here include grouping by trophic level or diet, by specialization, and by the nature of the predator's interaction with prey.

Functional classification

Classification of predators by the extent to which they feed on and interact with their prey is one way ecologists may wish to categorize the different types of predation. Instead of focusing on what they eat, this system classifies predators by the way in which they eat, and the general nature of the interaction between predator and prey species. Two factors are considered here: How close the predator and prey are physically (in the latter two cases the term prey may be replaced with host (biology)|host ). Additionally, whether or not the prey are directly killed by the predator is considered, with true predation and parasitoidism involving certain death.

True predation

A true predator can commonly be known as one which kills and eats another organism. Whereas other types of predator all harm their prey in some way, this form certainly kills them. Predators may hunt actively for prey, or sit and wait for prey to approach within striking distance, as in ambush predator s. Some predators kill large prey and dismember or chew it prior to eating it, such as a jaguar or a human ; others may eat their (usually much smaller) prey whole, as does a bottlenose dolphin swallowing a fish, or a snake , duck or stork swallowing a frog . Some animals that kill both large and small prey for their size (domestic cat s and dog s are prime examples) may do either depending upon the circumstances; either would devour a large insect whole but dismember a rabbit. Some predation entails venom which subdues a prey creature before the predator ingests the prey by killing, which the box jellyfish does, or disabling it, found in the behavior of the cone shell . In some cases the venom, as in rattlesnake s and some spider s, contributes to the digestion of the prey item even before the predator begins eating. In other cases, the prey organism may die in the mouth or digestive system of the predator. Baleen whale s, for example, eat millions of microscopic plankton at once, the prey being broken down well after entering the whale. Seed predation and egg predation are other forms of true predation, as seed s and egg (biology)|egg s represent potential organisms. Predators of this classification need not eat prey entirely, for example some predators cannot digest bone s, while others can. Some may eat only part of an organism, as in grazing (see below), but still consistently cause its direct death.

Grazing

Grazing organisms may also kill their prey species, but this is seldom the case. While some herbivores like zooplankton live on unicellular phytoplankton and have no choice but to kill their prey, many only eat a small part of the plant. Grazing livestock may pull some grass out at the roots, but most is simply grazed upon, allowing the plant to regrow once again. Kelp is frequently grazed in subtidal kelp forests, but regrows at the base of the blade continuously to cope with browsing pressure. Animals may also be 'grazed' upon; female mosquito s land on hosts briefly to gain sufficient protein s for the development of their offspring. Starfish may be grazed on, being capable of regenerating lost arms.

Parasitism

Parasites can at times be difficult to distinguish from grazers. Their feeding behavior is similar in many ways, however they are noted for their close association, with their host species. While a grazing species such as an elephant may travel many kilometers in a single day, grazing on many plants in the process, parasites form very close associations with their hosts, usually having only one or at most a few in their lifetime. This close living arrangement may be described by the term symbiosis , 'living together,' but unlike Mutualism (biology)|mutualism the association significantly reduces the fitness (biology)|fitness of the host. Parasitic organisms range from the macroscopic mistletoe , a parasitic plant , to microscopic internal parasites such as cholera . Some species however have more loose associations with their hosts. Lepidoptera ( butterfly and moth ) larvae may feed parasitically on only a single plant, or they may graze on several nearby plants. It is therefore wise to treat this classification system as a continuum rather than four isolated forms.

Parasitoidism

Parasitoids are organisms living in or on their host and feeding directly upon it, eventually leading to its death. They are much like parasites in their close symbiotic relationship with their host or hosts. Like the previous two classifications parasitoid predators do not kill their hosts instantly. However, unlike parasites, they are very similar to true predators in that the fate of their prey is quite inevitably death. A well known example of a parasitoids are the ichneumon wasp s, solitary insects living a free life as an adult, then laying eggs on or in another species such as a caterpillar. Its larva(e) feed on the growing host causing it little harm at first, but soon devouring the internal organs until finally destroying the nervous system resulting in prey death. By this stage the young wasp(s) are developed sufficiently to move to the next stage in their life cycle. Though limited mainly to the insect order Hymenoptera , Diptera and Coleoptera parasitoids make up as much as 10% of all insect species. Charles Godfray|Godfray, H.C.J. (1994). . Princeton University Press, Princeton. ISBN 0-691-03325-0, ISBN 0-691-00047-6. P. 20.

Degree of specialization

Among predators there is a large degree of specialization. Many predators specialize in hunting only one species of prey. Others are more opportunistic and will kill and eat almost anything (examples: human s, leopard s, and dog s). The specialists are usually particularly well suited to capturing their preferred prey. The prey in turn, are often equally suited to escape that predator. This is called an evolutionary arms race and tends to keep the populations of both species in equilibrium. Some predators specialize in certain classes of prey, not just single species. Some will switch to other prey (with varying degrees of success) when the preferred target is extremely scarce, and they may also resort to scavenger|scavenging or a herbivorous diet if possible.

Trophic level

Predators are often another organism's prey, and likewise prey are often predators. Though blue jay s prey on insect s, they may in turn be prey for cat s and snake s, which, in the latter's case, may themselves be the prey of hawk s. One way of classifying predators is by trophic level . Organisms which feed on autotroph s, the producers of the trophic pyramid , are known as herbivore s or primary consumers ; those that feed on heterotroph s such as animals are known as secondary consumers . Secondary consumers are a type of carnivore , but there are also tertiary consumers eating these carnivores, quartary consumers eating them, and so forth. Because only a fraction of energy is passed on to the next level, this hierarchy of predation must end somewhere, and very seldom goes higher than five or six levels, and may go only as high as three trophic levels (for example, a lion that preys upon large herbivores such as wildebeest which in turn eat grass es). A predator at the top of any food chain (that is, one that is preyed upon by no organism) is called an apex predator ; examples include the orca , sperm whale , anaconda , Komodo dragon , tiger , lion , Tiger shark , Nile crocodile , and most eagle s -- and even omnivorous humans and grizzly bear s. An apex predator in one environment may not retain this position as a top predator if introduced to another habitat, such as a dog among American alligator|alligator s or a snapping turtle among jaguar s; a predatory species introduced into an area where it faces no predators, such as a domestic cat or a dog in some insular environments, can become an apex predator by default.

Many organisms (of which humans are prime examples) eat from multiple levels of the food chain and thus make this classification problematic. A carnivore may eat both secondary and tertiary consumers, and its prey may itself be difficult to classify for similar reasons. Organisms showing both carnivory and herbivory are known as omnivore s. Even herbivores such as the giant panda may supplement their diet with meat. scavenger|Scavenging of carrion provides a significant part of the diet of some of the most fearsome predators. Carnivorous plant s would be very difficult to fit into this classification, producing their own food but also digesting anything that they may trap. Organisms which eat detritivore s or parasite s would also be difficult to classify by such a scheme.

Predation as competition

An alternative view offered by Richard Dawkins is of predation as a form of Competition (biology)|competition : the gene s of both the predator and prey are competing for the body (or ' survival machine ') of the prey organism.Dawkins, R. (1976). The Selfish Gene . Oxford University Press. ISBN 0-19-286092-5. This is best understood in the context of the gene centered view of evolution . Another manner in which predation and competition are connected is throughout intraguild predation . Intraguild predators are those that kill and eat other predators of different species at the same trophic level, and thus that are potential competitors.

Ecological role

Predators may increase the biodiversity of communities by preventing a single species from becoming dominant. Such predators are known as keystone species and may have a profound influence on the balance of organisms in a particular ecosystem . Introduction or removal of this predator, or changes in its population density, can have drastic cascading effects on the equilibrium of many other populations in the ecosystem. For example, grazers of a grassland may prevent a single dominant species from taking over.Botkin, D. and E. Keller (2003). Enrivonmental Science: Earth as a living planet . John Wiley & Sons. ISBN 0-471-38914-5. P.2.

The elimination of wolves from Yellowstone National Park had profound impacts on the trophic pyramid . Without predation, herbivores began to over-graze many woody browse species, affecting the area's plant populations. Additionally, wolves often kept animals from grazing in riparian areas, which protected beavers from having their food sources encroached upon. The removal of wolves had a direct effect on beaver populations, as their habitat became territory for grazing.William J. Ripple and Robert L. Beschta. "Wolves and the Ecology of Fear: Can Predation Risk Structure Ecosystems? " 2004.
Furthermore, predation keeps hydrological features such as creeks and streams in normal working order. Increased browsing on willows lenr and conifers along Blacktail Creek due to a lack of predation resulted in channel incision because those species helped slow the water down and hold the soil in place.

Adaptations and behavior

The act of predation can be broken down into a maximum of four stages: Detection of prey, attack, capture and finally consumption.Alcock, J. (1998). Animal Behavior: An Evolutionary Approach (6th edition). Sunderland, Mass.: Sinauer Associates, Inc. ISBN 0-87893-009-4. The relationship between predator and prey is one which is typically beneficial to the predator, and detrimental to the prey species. Sometimes, however, predation has indirect benefits to the prey species, though the individuals preyed upon themselves do not benefit.Dawkins, R. (2004). ''The Ancestor's Tale . Boston: Houghton Mifflin. ISBN 0-618-00583-8. This means that, at each applicable stage, predator and prey species are in an evolutionary arms race to maximize their respective abilities to obtain food or avoid being eaten. This interaction has resulted in a vast array of adaptation s in both groups.

One adaptation helping both predators and prey avoid detection is camouflage , a form of crypsis where species have an appearance which helps them blend into the background. Camouflage consists of not only color, but also shape and pattern. The background upon which the organism is seen can be both its environment (e.g. the praying mantis to the right resembling dead leaves) or other organisms (e.g. zebra s' stripes blend in with each other in a herd, making it difficult for lion s to focus on a single target). The more convincing camouflage is, the more likely it is that the organism will go unseen.

Mimic ry is a related phenomenon where an organism has a similar appearance to another species. One such example is the drone fly , which looks a lot like a bee , yet is completely harmless as it cannot sting at all. Another example of batesian mimicry is the Automeris io|io moth , ( Automeris io ), which has markings on its wings which resemble an owl 's eyes. When an insectivorous predator disturbs the moth, it reveals its hind wings, temporarily startling the predator and giving it time to escape. Predators may also use mimicry to lure their prey, however. Female firefly|fireflies of the genus Photuris (genus)|Photuris , for example, copy the light signals of other species, thereby attracting male fireflies which are then captured and eaten (see aggressive mimicry ).

Predator

While successful predation results in a gain of Biological thermodynamics|energy , hunting invariably involves energetic costs as well. When hunger is not an issue, most predators will generally not seek to attack prey since the costs outweigh the benefits. For instance, a large predatory fish like a shark that is well fed in an aquarium will typically ignore the smaller fish swimming around it (while the prey fish take advantage of the fact that the apex predator is apparently uninterested). Surplus killing represents a deviation from this type of behaviour. The treatment of consumption in terms of cost-benefit analysis is known as optimal foraging theory , and has been quite successful in the study of ethology|animal behavior . Costs and benefits are generally considered in energy gain per unit time, though other factors are also important, such as essential nutrient s that have no caloric value but are necessary for survival and health.

Social predation offers the possibility of predators to kill creatures larger than those that members of the species could overpower singly. Lion s, hyena s, wolf|wolves , dhole s, African wild dog s, and piranha s can kill large herbivores that single animals of the same species could never dispatch. Social predation allows some animals to organize hunting|hunts of creatures that would easily escape a single predator; thus chimpanzee s can prey upon colobus monkey s, and Harris's Hawk s can cut off all possible escapes for a doomed rabbit. Extreme specialization of roles is evident in some hunting that requires co-operation between predators of very different species: human s with the aid of falcon s or dog s, or fishing with cormorant s or dogs. Social predation is often very complex behavior, and not all social creatures (for example, domestic cat s) perform it. Even without complex intelligence but instinct alone, some ant species can destroy much-larger creatures.

Size-selective predation involves predators preferring prey of a certain size. Large prey may prove troublesome for a predator, while small prey might prove hard to find and in any case provide less of a reward. This has led to a correlation between the size of predators and their prey. Size may also act as a refuge (ecology)|refuge for large prey, for example adult elephants are generally safe from predation by lions, but juveniles are vulnerable.

It has been observed that well-fed predator animals in a lax captivity (for instance, pet or farm animals) will usually differentiate between putative prey animals who are familiar co-inhabitants in the same human area from wild ones outside the area. This interaction can range from peaceful coexistence to close companionship; motivation to ignore the predatory instinct may result from mutual advantage or fear of reprisal from human masters who have made clear that harming co-inhabitants will not be tolerated. Pet cat s and pet mouse|mice , for example, may live together in the same human residence without incident as companions. Pet cats and pet dog s under human mastership often depend on each other for warmth, companionship, and even protection, particularly in rural areas.

Antipredator adaptations

Antipredator adaptations have evolved in prey populations due to the selective pressures of predation over long periods of time.

Aggression

Predatory animals often use their usual methods of attacking prey to inflict or to threaten grievous injury to their own predators. The electric eel uses the same electrical current to kill prey and to defend itself against animals ( anaconda s, caiman s, jaguar s, egret s, cougar s, giant otter s, humans, and dogs) that ordinarily prey upon fish similar to an electric eel in size; the electric eel thus remains an apex predator in a predator-rich environment. A predator small enough to be prey for others, the domestic cat uses its formidable teeth and claws as weapons against animals that might confuse a cat with easier prey. Many non-predatory prey animals, such as a zebra , can give a strong kick that can maim or kill, while others charge with tusks or horns.

Mobbing behavior

Mobbing behavior occurs when members of a species drive away their predator by co-operation (evolution)|cooperatively attacking or harassing it. Most frequently seen in bird s, mobbing is also seen in other social animals. For example, nesting gull colonies are widely seen to attack intruders, including humans. Costs of mobbing behavior include the risk of engaging with predators, as well as energy expended in the process, but it can aid the survival of members of a species.

While mobbing has convergent evolution|evolved independently in many species, it tends to be present only in those whose young are frequently preyed on, especially birds. It may complement crypsis|cryptic behavior in the offspring themselves, such as camouflage and hiding. Mobbing calls may be made prior to or during engagement in harassment.

Mobbing can be an interspecies activity: it is common for birds to respond to mobbing calls of a different species. Many birds will show up at the sight of mobbing and watch and call, but not participate. It should also be noted that some species can be on both ends of a mobbing attack. Crows are frequently mobbed by smaller songbirds as they prey on eggs and young from these birds' nests, but these same crows will cooperate with smaller birds to drive away hawks or larger mammalian predators. On occasion, birds will mob animals that pose no threat.

Advertising unprofitability

A Thomson's Gazelle seeing a predator approach may start to run away, but then slow down and stot . Stotting is jumping into the air with the legs straight and stiff, and the white rear fully visible. Stotting is maladaptive for outrunning predators; evidence suggests that stotting animal communication|signal s an unprofitable chase. For example, cheetahs abandon more hunts when the gazelle stots, and in the event they do give chase, they are far less likely to make a kill.

Aposematism , where organisms are brightly colored as a warning to predators, is the antithesis of camouflage. Some organisms pose a threat to their predators—for example they may be poison ous, or able to harm them physically. Aposematic coloring involves bright, easily recognizable and unique colors and patterns. Upon being harmed ( e.g. , stung) by their prey, the appearance in such an organism will be memory|remembered as something to avoid. While that particular prey organism may be killed, the coloring benefits the prey species as a whole.

Domestic cats, animals similar in size to such prey species as rabbits, make a hissing sound reminiscent of a snake, advertising that they can put up formidable defenses for their size. Such can deter confrontations harmful to both the cat and to an animal in search of small animals as prey.

Chemical defense

Some organisms have evolved chemical weapons which are effective deterrents against predation. It is most common in insects , but the skunk is a particularly dramatic mammal ian example. Other examples include the Bombardier beetle which can accurately shoot a predator with a stream of boiling poison, the Ornate moth which excretes a frothy alkaloid mixture, and the Pacific beetle cockroach sprays a quinone mixture from modified spiracle s.

Terrain Fear Factor

The "terrain fear factor" is an idea which assesses the risks associated with predator/prey encounters. This idea suggests that prey will change their usual habits to adjust to the terrain and its effect on the species' predation. For example, a species may forage in a terrain with a lower predation risk as opposed to one with high predation risk.

Population dynamics

It is fairly clear that predators tend to lower the survival and fecundity of their prey, but on a higher level of organization, population s of predator and prey species also interact. It is obvious that predators depend on prey for survival, and this is reflected in predator populations being affected by changes in prey populations. It is not so obvious, however, that predators affect prey populations. Eating a prey organism may simply make room for another if the prey population is approaching its carrying capacity .

The population dynamics of predator-prey interactions can be modelled using the Lotka–Volterra equation s. These provide a mathematical model for the cycling of predator and prey populations. Predators tend to select young, weak, and ill individuals.Genovart M, Negre N, Tavecchia G, Bistuer A, Parpal L, Oro D. (2010). PLoS One. 19;5(3):e9774. PMID 20333305

Evolution of predation

Predation appears to have become a major selection pressure shortly before the Cambrian period—around —as evidenced by the almost simultaneous development of calcification in animals and algae, and predation-avoiding burrowing. However, predators had been grazing on micro-organisms since at least .

Humans and predation

As predators

Humans are omnivorous and use tools to exploit their environments; from snare s, clubs, spear s, fishing gear , firearm s to boats and motor vehicles. Humans even use other predatory species, (such as dogs, cormorant s, and falcon s) in hunting and fishing; some people even enlist such non-predatory beasts, like horses, camels, and elephants in getting approaches to prey.

Humans have reshaped huge expanses of the world as ranges and farms for the raising of livestock, poultry, and fish farming|fish to be eaten as meat. However, it can be debated whether or not harvesting livestock fits strictly in the definition of predation.

Human raising and eating of livestock is part of agriculture , and involves the feeding of and caring for animals, followed by their being slaughtered with an appropriate tool, cutting up, and cooking. In many cultures, animals are hunted or farmed by specialists (such as ranchers or fishermen ), brought to a marketplace, and sold in pieces to the people who actually consume the meat.

As prey

A lone naked human is at a physical disadvantage to other comparable apex predators in areas such as speed, bone density, weight, and physical strength. Humans also lack innate weaponry such as claws. Without crafted weapons, society , or cleverness, a lone human can easily be defeated by fit predatory animals, such as wild dogs, big cats and bears. There are even recorded instances of lone humans being preyed upon by large carnivores (see Man-eater ). However humans are not solitary creatures; they are social animals with highly developed social behaviors. Further humans and their ancestors (such as Homo erectus ) have been using stone tools and weapons for well over a million years. Anatomically modern humans have been apex predators since they first evolved, and many species of carnivorous megafauna actively avoid interacting with humans; the primary environmental competitor for a human is other humans. The one subspecies of carnivorous megafauna that does interact frequently with humans in predatory roles is the domestic dog , but usually as a partner in predation especially if they hunt together. Cannibalism has occurred in various places, among various cultures, and for various reasons. At least a few people, such as the Donner party , are said to have resorted to it in desperation.

In conservation

Predators are an important consideration in matters relating to Wildlife conservation|conservation . Introduced species|Introduced predators may prove too much for populations which have not coevolved with them, leading to possible extinction . This will depend largely on how well the prey species can adapt to the new species, and or not the predator can turn to alternative food sources when prey populations fall to minimal levels. If a predator can use an alternative prey instead, it may shift its diet towards that species, while still eating the last remaining prey organisms. On the other hand the prey species may be able to survive if the predator has no alternative prey—in this case its population will necessarily crash following the decline in prey, allowing some small proportion of prey to survive. Introduction of an alternative prey may well lead to the extinction of prey, as this constraint is removed.
Predators are often the species endangered themselves, especially apex predators who are often in competition with humans. Interspecific competition|Competition for prey from other species could prove the end of a predator—if their ecological niche overlaps completely with that of another the competitive exclusion principle requires only one can survive. Loss of prey species may lead to coextinction of their predator. In addition, because predators are found in higher trophic levels, they are less abundant and much more vulnerable to extinction.

Biological pest control

Predators may be put to use in conservation efforts to control introduced species. Although the aim in this situation is to remove the introduced species entirely, keeping its abundance down is often the only possibility. Predators from its natural range may be introduced to control populations, though in some cases this has little effect, and may even cause unforeseen problems. Besides their use in conservation biology , predators are also important for controlling Pest (organism)|pest s in agriculture . Natural predators are an environmentally friendly and sustainable way of reducing damage to crops, and are one alternative to the use of chemical agents such as pesticide s.

Copyright Citations

This article is licensed under the GNU License
Click here for original article: Prey


1. The Bad Seeds 2. Jacques Brel 3. Jose Carreras 4. Richard Chamberlain 5. Fecal Matter 6. Mirella Freni 7. Girls Against Boys 8. GVSB 9. Scott Joplin 10. Killing Joke 11. Kosher 12. Mandrill 13. Mansun 14. Wynton Marsalis 15. Mimic 16. Moose 17. Natural 18. Nectar 19. Paradise Lost 20. Pigface 21. Platypus 22. Primal Fear 23. Venom 24. Zoviet France 25. Sanctity

Undetermined Music Artists