Predator–Prey Relationships | santemontreal.info
A predator is an organism that eats another organism. The prey is Some examples of predator and prey are lion and zebra, bear and fish, and fox and rabbit. This paper will examine the different relationships between predator and prey; examples of prey, and the influence between predators and prey concerning. Predation is a biological interaction where one organism, the predator, kills and eats another and includes a wide variety of feeding methods; and some relationships that result in the prey's death are not generally called predation.
For a more detailed approach, Lima and Dill provides a readable synthesis of behavioral trade-offs involved in predator-prey interactions, one that is broadened in ecological scope in Lima and, written later, Chase, et al. Dawkins and Krebs provides an introduction to the evolution of the predator-prey arms race, while Abrams provides a critical approach to the arms race using a largely theoretical background for the predator-prey interaction, especially in terms of its evolutionary stability.
The evolution of predator-prey interactions: Annual Review of Ecology and Systematics Abrams supports his arguments with a strong theoretical background beginning with early Lokta-Volterra models and advancing through gaps in current models. Barbosa Pedro, and Ignacio Castellanos, eds. Ecology of predator-prey interactions. It examines several important arguments about the relevance of predation in changing interactions between competitors.
Dawkins, Richard, and John R. Arms races between and within species. This warning coloration in turn saves the organisms life as well as helps the predator to avoid a distasteful, maybe even toxic meal.
Defense mechanisms vary drastically, and change according to different circumstances. The ability of an organism to survive depends solely on how well it can use it"s defense mechanisms to prolong it"s life.
The next topic of discussion is the relationship between predators and their prey. Predators and prey effect each other from day to day interactions to the evolution of each other. Predator and prey populations move in cycles, the number of predators will influence the number of prey and the number of prey available will influence the population of predators.
Predators and their prey also influence the evolution of each other. Michael Brooke points out that natural selection should favor traits that help a species survive. A general example would be the increase in speed of potential prey.
These evolutionary traits are usually followed with an evolution in the predator. Using the increase of maximum speed as an example, evolution will favor predators that are fast enough to continue to catch the prey. This will lead to the evolution of a faster predator.
Brooke compares the evolutionary process to an arms race, for both sides have to keep advancing in order to stay alive. In an ideal cycle, the predators and prey will establish stable populations. Predators play a crucial role in the population of the prey.
The importance of predators can be seen in the Kaibab Plateau in Arizona Boughey, At the beginning of this century, 4, deer inhabitedacres of land. Over the next 40 years, mountain lion were removed from the area. At the same time, over 7, coyote were removed. When the predators were removed, the population jumped up todeer by Boughey, Without predators, the prey could not establish a stable population and the land supported a much smaller number than the estimated carrying capacity of 30, Boughey, The example can work in reverse; an increased number of predators feeding on a limited number of prey can lead to the extinction of the predators.
This is the case with the ancient trilobites, these marine anthropods died million years ago in the Permian age Carr, According to Carr, over 60 families of this animal have been found in fossil records. This highly successful creature became extinct due to changes in the prey population. During the Permian period, glaciation took place that changed the availability of the trilobites food source, algae. One may conclude that the prey population dwindled and the trilobites could no longer support themselves.
Parasites feed off of their prey just as predators do Ricklefs,but it is in the interest of the parasite to keep it"s host alive. In some cases, the parasite will act so efficiently that it will lead to the death of it"s host, but most parasites can achieve a balance with their hosts. Even though parasites might not lead directly to the death of it"s host, it can effect the host in a variety of other ways.
A host could become weaker and not be able to compete for food or reproduce, or the parasite could make it"s host less desirable to mate with, as is the case with Drosophila nigrospiracula the Sanoran desert fruit fly. Michal Polak et al. The mites feed off of animal dung and rotting plant tissue Polak et al. But Polak et al. This suggests that females are selective when choosing their mates.
With females choosing not to mate with males that are infected with the mites, the evolution of the species is being affected. Males that exhibit resistance to mites are favored, so these characteristics will be passed onto the offspring, leading to the development of mite resistant Drosophila nigrospiracula.
There are several theories on what basis the mites affect the males. Based on the research compiled by Polak et al. Whatever the case, parasites have an effect on their prey.
In a similar scenario, the parasitic relationship between cuckoos and other birds, the development of resistance to a parasite leads to the evolution of the parasite. This polymorphism is known as coevolution. Nitecki uses grass as a simple example of this phenomenon Grass evolves a resistance to a strain of rust by making a single gene substitution, and the rust counters this step with it"s own single gene substitution Nitecki, He adds that many parasites are host specific, so they are keyed into their host and can adjust to the appropriate changes when necessary.
This is why parasites are a continual problem, not just an irritant that is rendered extinct by one simply change in the host"s evolution. This helps explain why the cuckoo continues to successfully lay it"s eggs in the nests of Meadow Pipits, Reed Warblers, Pied Wagtails, and Dunnocks Brooke, According to Brookethe host birds usually are deceived by the cuckoo"s egg and then raise the cuckoo chick instead of their own.
By examining the cuckoo, it is easy to see how evolution has perfected the parasitic process. According to Brookethe cuckoo will watch it"s prey as it builds its nest, wait until both parents are away from the nest, then enter the nest to remove one of the original eggs and lay it"s own.
Each species of cuckoo has evolved to specifically target one of the four possible birds. According to Brooke, the Great Reed Warbler-Cuckoo will lay an egg that is similar in size and color to the hosts, and the cuckoo has perfected the intrusion to a science, spending about 10 seconds in the nest of it"s host. The next step of parasitism comes once the cuckoo has hatched. The process that the chick goes through is described by Brooke ; the chick hatches before the rest of the clutch due to it"s shorter incubation period and then pushes the other eggs out of the nest.
The host family will not abandon the chick, while the exact reason is not known, there are several theories. According to Brookethe parents have nothing to compare the chick with or do not decide that it is too late to raise a new clutch and will raise their adopted chick.
Brooke describes some of the tests carried out in his research concerning the factors that influence the rejection rate of cuckoo eggs.
Most birds will not reject eggs that are similar too their eggs, but larger eggs are have a higher rate of rejection. But if the host birds see the cuckoo in the nest, then the rate of rejection is much increased Brooke,which explains why cuckoos have evolved such a fast predatory process. Brooke shows an example of the evolutionary process at work when he examines the Dunnock"s relationship with the cuckoo The Dunnock-Cuckoo has not developed an egg that mimics the Dunnock egg because Dunnocks accept eggs of any size and color.
Therefore, Dunnocks have not yet developed any defenses against the cuckoo, so the cuckoo has no need to develop any traits to aid in parasitism. Brooke showed other examples of evolution by testing isolated species of hosts. These birds were not as discriminating, implying that they lacked the evolutionary advancements of detecting and rejecting parasitic eggs. The cuckoo and their hosts are clear examples of how both the predators and they prey affect the evolution of each other.
Many animals exhibit group behavior; worker bees serve the queen bee and wolves follow an established ranking system. But when members of the same species endanger each other for individual protection, the member of the species that faces death is being used as prey by the member of the species surviving. Robert Heisohn describes this relationship in lions when territorial disputes occur. The leader lion will be meters ahead of the laggards when approaching an invading lion Heinsohn, The leader will face severe injury and even death while the laggards reduce their risk by staying behind Heinsohn, Similar behavior has been observed in many species of birds.
The advent of agricultural societies defined by the growing of field crops eventually brought cities and full-time division of labor. Societies became much larger, each identifying itself with a specific geographic region over which the state claimed ownership.
Social stratification also appeared, sometimes in the form of a rigid, intergenerational caste system. At the head of the state was a divine king, whose family shared in his coercive authority as well as his privilege and prestige. At the same time, however, levels of interpersonal violence excluding warfare, i.
The result then was the establishment of an empire, with a central state systematically siphoning wealth from peripheral colonies. Often people from conquered lands were imported to the capital as slaves. This simple schema runs the risk of oversimplification; indeed, recent research has uncovered surprising exceptions at each stage along the way—including hunters and gatherers who were mostly sedentary, and early cities that were egalitarian and showed no evidence of stratification.
The path of social complexification and stratification often meandered and doubled back. Nevertheless, the essential trend persisted: A relatively small elite group took charge and gained wealth and power. The masses, meanwhile, were held in a condition of relative poverty, their labor organized and controlled by overlords. Among social scientists, there have been two schools of thought with regard to the origin of stratification and complexity; Joseph Tainter, in The Collapse of Complex Societiessummarizes these schools of thought clearly.
The state, in this view, is based on divided interests, on domination and exploitation, on coercion, and is primarily a stage for power struggles.
Tainter, who regards the development of complexity as a problem-solving strategy adopted by society as a whole, suggests that a synthesis of conflict and integrationist views is needed, but leans toward the integrationist position.
The most interesting recent work related to this question has come from cultural evolution theorists including Peter Turchin—who suggests that near-constant warfare was the mechanism that led from one stage of social organization to the next. In essence, he persuasively argues that internal complexity based on cooperation enabled societies to compete more effectively with one another under conditions of frequent bloody conflict. In developing the predation metaphor, I have so far compared human society to a wild ecosystem.
However, once humans had left hunting and gathering behind, they no longer inhabited an entirely wild ecosystem. Increasingly, they were domesticating plants and animals and altering landscapes to support domesticated species. Humans domesticating an animal species must have had to organize their own thinking and behavior in order to tame, feed, and selectively breed their animal captives.
Once we domesticated prey animals, did we replicate that thinking, and those behaviors, within human society? Domestication began before, or concurrent with, the development of stratification and complexity—not after it though the process has continued to the present.
Museletter # Human Predators, Human Prey - Richard Heinberg
Thus it is extremely unlikely that human slavery served as a model or inspiration for animal domestication; however, the reverse is entirely possible. However, candidate areas are problematic. In the case of Pre-Colombian America, domesticated animals consisted primarily of dogs and turkeys in North America; and guinea pigs, llamas, and alpacas in South America.
Slavery was institutionalized among at least some indigenous peoples of the Americas: Some captives were ritually sacrificed in ceremonies that sometimes involve ritual torture and cannibalism.
Many groups permitted captives to gradually become integrated into the tribe. Slaves were not bought and sold, but could be traded or exchanged with other tribes. The hypothesis appears difficult to test in this way. But indirect evidence supports it.
Echoing the earlier work of ecologist Paul Shepardanthropologist Tim Ingold at the University of Aberdeen in Scotland, in his book The Perception of the Environmentargues that foraging peoples regarded animals as their equals, while pastoralists tended to treat their domesticated animals as property to be mastered and controlled. Archaeologist Guillermo Algaze at the University of California in San Diego finds that the first city-states in Mesopotamia were built on the principle of transferring methods of control from animals to fellow humans: At the other end of the spectrum are modern citizens exposed in childhood to universal compulsory education —which, with its bells, routines, inculcation of behavioral norms, segregation of children by age, and ranking by achievement, results in adults prepared for life in an orderly, stratified, scheduled, and routinized society.
Predation could be said to foster its own psychology. Predators non-human and human do not appear to view their prey with much compassion; predation is a game to be played and enjoyed.Difference between Predation and Parasitism
If orcas and cougars could speak, they might echo the typical words of the professional bill collector: For a family living on a farm, daily proximity with livestock entails getting to know individual animals, a few of which may earn sympathy and respect especially from children.
Many keepers of livestock genuinely care for their animals, treating them when they are sick and making sure that, when the animals are finally killed for food, the killing occurs with minimal pain and suffering.
But when any animal comes to be seen as food, empathy is often attenuated—as it is in many slaughterhouses and fishing trawlers. Some domesticates became workers horses, oxen, mules or pets ; the latter provided affection, companionship, amusement, and beauty. Today, many people lavish extraordinary care on their pets as ancient Egyptians did with their catswhile society heaps attention and riches on elite musicians, actors, artists, athletes, models, and authors. Cooperative complex institutions such as cooperative businesses are numerous and successful.
Further, some industrial societies feature much lower levels of wealth inequality than do others. This is a point to which we will return toward the end of the essay.