J1++The+Nature+of+Predation

__**The Nature of Predation:**__ Predation is the defined as the consumption of the whole or part of another creature, which is termed "prey". This leads rise to three types of predators: //True Predators:// These are predators that kill their prey soon after engaging them. //Grazers:// These creatures kill their prey over a period of time and only eat bits and pieces. //Parasites:// These predators live in close proximity or within a single creature, referred to as the "host", often living in the tissue and feeding gradually on the flesh of the host.

__**Carnivores and Herbivores**__: Creatures can be divided into three generalizations, herbivore or carnivore, or, if they tread the line between the two, omnivore. Though they differ in prey types, both of the creatures they use as sustenance defend themselves through structural devices, or physical impediments to being eaten. This could be a poison in the case of some frogs and plants, a tough outer carapace in the case of a snail or pangolin, or even a large array of spines, such as the porcupine or lionfish (which has the added bonus of combining poison with razor sharp spines.) For herbivores, their prey tends to avoid death through chemical defenses such as poisons, which carnivores' prey avoid this through behavioral tics, like running, hiding or fighting back. //Herbivores:// Herbivores are defined as animals that consume plant matter for sustenance. For herbivores, their prey tends to avoid death through chemical defenses such as poisons. This can manifest itself as spines coated poisons, or even a milky coating, such as on some types of ferns. //Predators:// Predators are animals that consume other animal matter for sustenance. //Omnivores:// Omnivores eat a combination of plant and animal matter.

__**Generalists and Specialists:**__ Aside from being defined by what types of matter they eat, they can also be defined by the broadness of their diet. These types are called generalists or specialists. Larger animals tend to be less selective in their choice of prey, thus large mammals tend to eat many types of creatures. //Generalists:// Generalists are the easiest to define, they are animals that eat any animals they come across, with little to no reservations in terms of the prey they elect to consume. //Specialists:// Specialists are much more selective than generalists. They elect one or two types of plant species with similar chemical defenses that they have evolved to cope with in their digestive system. They are also defined as monophagous, meaning they consume only one type of prey, or oligophagous, which means eating a few types of prey. They can also be called polyphagous, which means they eat many times of plants but avoid the poisonous parts.

__**The Impact of Predators on Prey Population Size:**__ Whether or not predators or parasites control the population depends on a number of factors. i) Predators may only be a small factor in controlling the population, and the disappearance of one predator can have little to no effect on the population of its prey. In many cases there are more severe factors in the mortality of creatures. ii) Predators are only there to consume excess prey in order to balance the ecosystem. For instance, in Wytham Wood, England, there was an increase in predation of great tits after an increase in sparrowhawks, their predators. However, despite these norms, there are, in fact, instances in which predators have devastated populations of prey animals. This often occurs when a predator is introduced to a new ecosystem and can thrive, such as the introduction of northern pike to Sabattus Lake in Maine. There were no other predators (other than humans, through fishing) to control the spread of these dangerous fish, and in turn they consumed a large chunk of the native bass population.

The Lotka-Volterra model is a way of examining the dynamics of the predator-prey relationship. It makes three assumptions. i) There is one predator and one prey species in the interaction. ii) Prey numbers decrease if predators rise and vice versa. iii)Predator numbers increase when prey increases, and decrease when prey numbers fall. This shows that there is a clear cycle in this relationship, and that when predators increase, prey falls, which leads to predators dying off and prey rising. It is a timeless cycle.
 * __Predator-Prey Model:__**