page_title: Community (ecology)
section_title: Predation
hierarchical_section_title: Community (ecology) / Interspecific interactions / Predation
caption_attribution_description: English: A generalised graph of a predator-prey population density cycle. The blue curve represents the predator, the orange curve the prey.
context_page_description: In ecology, a community is a group or association of populations of two or more different species occupying the same geographical area at the same time, also known as a biocoenosis. The term community has a variety of uses. In its simplest form it refers to groups of organisms in a specific place or time, for example, "the fish community of Lake Ontario before industrialization".
  Community ecology or synecology is the study of the interactions between species in communities on many spatial and temporal scales, including the distribution, structure, abundance, demography, and interactions between coexisting populations. The primary focus of community ecology is on the interactions between populations as determined by specific genotypic and phenotypic characteristics.
  Community ecology also takes into account abiotic factors e.g. annual temperature or soil pH. These non-living factors can influence the way species interact with each other. Abiotic factors filter the species that are present in the community, and therefore community structure. For example, the difference in plants present in the desert compared to the tropical rainforest is dictated by the annual precipitation.
context_section_description: Predation is hunting another species for food. This is a positive–negative interaction, the predator species benefits while the prey species is harmed. Some predators kill their prey before eating them, also known as kill and consume. For example, a hawk catching and killing a mouse.
  Other predators are parasites that feed on prey while alive, for example a vampire bat feeding on a cow. Parasitism can however lead to death of the host organism over time. 
  Another example is the feeding on plants of herbivores, for example a cow grazing.
  Predation may affect the population size of predators and prey and the number of species coexisting in a community.
  Predation can be specialist, for example the least weasel predates solely on the field vole. Or generalist, e.g. polar bear primarily eats seals but can switch diet to birds when seal population is low.  
  Species can be solitary or group predators. Advantage of hunting in a group means bigger prey can be taken, however the food source has to be shared. Wolves are group predators, whilst tigers are solitary. 
  Predation is density dependant, often leading to population cycles. When prey is abundant predator species increases, thus eating more prey species and causing the prey population to decline. Due to lack of food the predator population declines. Due to lack of predation the prey population increases. See Lotka–Volterra equations for more details on this. A well-known example of this is  lynx- hare population cycles seen in the north.  
  Predation can result in coevolution –  evolutionary arms race, prey adapts to avoid predator, predator evolves. For example, a prey species develops a toxin that will kill its predator, predator evolves resistance to the toxin making it no longer lethal.
caption: A generalised graph of a predator-prey population density cycle
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