Predation is a type of ecological interaction where one of the species kills and feeds on the other.
- The organism that kills and feeds on the dead organism is called the predator, whereas the organism that gets killed is called the prey.
- Predation is different from scavenging on dead organisms, but predators also scavenge as a part of their feeding behavior.
- Predatory organisms can either hunt as solitary hunters or group hunters where a group of species looks for prey together.
- The interaction is positive for the predator as it obtains energy for survival and reproduction, whereas detrimental for the prey.
- The most common form of predation is observed between two species from two different trophic levels in the food chain, but there are some exceptions.
- Even though predation is often associated with carnivorous animals, there are plants and insects that indulge in predatory activities.
- Predation is an essential interaction as it plays an important role in maintaining the population size in different communities which also promotes biodiversity.
- Predators are highly specialized organisms with acute senses required to catch the prey. These animals actively search for or pursue prey for long periods of time. Once detected, they assess whether to attack it before finding a good time to kill the prey.
- The solitary hunters like tiger pursue and attack the prey alone, whereas a wolf pack might attack prey as a group and share the resources.
- The prey also develops different antipredator adaptations like camouflage, mimicry, and alarm calls to protect themselves from the predators.
- In a complex environment where multiple predators feed on the same prey, competition might arise between such predators.
Types of Predation
Predation is classified into different types on the basis of the prey and the relationship between the predator and the prey.
- Carnivory is the most common type of predation where the predator kills the prey and feeds on its flesh.
- The predators involved in carnivory are often large animals like tier, shark, and wolf that feed on smaller animals like rabbits and deer.
- Carnivory is common in higher animals, and the predators or carnivores exist in different sizes and feed on different groups of smaller animals.
- This type of predation can be further classified depending on their feeding habits. Obligate carnivores are animals that exclusively feed on animal’s flesh for their survival. Facultative carnivores are animals that can feed on meat, but the flesh is not required for survival.
- Wolves are carnivorous animals that hunt and feed on large herbivores like deer, elk, and sheep. These also feed on smaller animals like rodents, hares, and beavers.
- These usually hunt in packs, and the predation is facilitated by different adaptations like strong jaws, heightened senses, and powerful bodies.
- The wolf pack consists of female wolves that care and defend the pups and male wolves involved in foraging and providing food.
- The wolves communicate with each other by facial expression and scent marking. The territory of wolf packs depends on the availability of prey and defenses against neighboring packs.
- Herbivory is a type of predation where the predators feed on autotrophs like plants and algae.
- Herbivory is not usually considered a type of predation as the predatory interaction is often associated with carnivorous animals.
- Like in all other forms of predations, the predators and prey in herbivorous interaction develop different forms of adaptation.
- Many herbivores have adaptations that enable them to determine which plants contain high-quality nutrients and fewer defensive features.
- Even though predation is supposed to harm the prey, some plants might get benefitted from the interaction. The herbivores feed on plant fruits and result in the dispersal of seeds to newer areas.
- The giraffe is a herbivore that feeds on the leaves of different plants and grass. Acacia trees are one of the common food sources for giraffes.
- Giraffes have adaptive strategies like long necks that allow them to reach leaves and fruits present high up in the trees.
- These are known to eat hundreds of pounds of leaves in a week. Since they mostly feed on leaves and bud the proportion of grass in their diet is quite low.
- The prey plants like acacia plants also develop defense mechanisms like the release of toxic substances in their leaves and ethylene gas which signals the surrounding trees to produce the toxins.
- Parasitism is also a form of predation where the parasite consumes nutrients from the host resulting in a decrease in fitness of the host and even death.
- In extreme cases, the parasites produce different forms of the disease at which point the parasites are called pathogens.
- Even though parasites usually do not kill their hosts, a distinct group of parasites termed parasitoids are known to feed on the host and eventually cause them to die.
- The parasitic organism is much smaller than the host in most cases which is different from the size of predators and prey in predation.
- Tapeworm is one of the common parasites in human beings and cattle which is found in the digestive tract of the hosts.
- The organism reaches the intestine through contaminated food and drinks where it attached itself to the intestinal wall.
- The attached head of the organism has different structures like hooks and suckers, which allows the organism to obtain nutrients from the digestive walls.
- The parasitic interaction might result in a lack of nutrition and other digestive disorders in the host.
- A tapeworm doesn’t usually kill the host, but these can live within the host for as many as 30 years resulting in prolonged parasitism.
- Mutualism is a type of interaction between two species where both species are benefitted from the interaction.
- One of the species provides the other with some resource or service, and the other also reciprocates with a benefit.
- Mutualism doesn’t result in the death of any species as both the species obtain the benefits.
- Mutualism, unlike other predatory interactions, require that involved species have similar functional and ecological features.
Example- Gut microorganism in humans
- Different parts of the human body consist of a group of beneficial microorganisms that exist in a mutual interaction with the host.
- Gut microflora is one of the most prominent and largest microflora in human beings. These microorganisms colonize all the parts of the digestive tract.
- The microorganisms produce different digestive enzymes that help in the digestion of food in human beings. Besides, these also protect the host from pathogenic microorganisms.
- In turn, the host provides them with nutrients and living space. The mutualistic relationship can last for years.
- Cannibalism is also a type of predatory interaction where an organism of a species feeds on the other organism of the same species.
- It is a common ecological interaction in animals and has been observed in about 1500 different species.
- Cannibalism is usually observed in environments that are poor in nutrients which lead to the species feeding on each other.
- Cannibalism is an important event that helps to maintain species populations so that the food and other resources are more readily available to the competing population.
- Cannibalism is particularly common in the aquatic ecosystem, with about 90% of the organisms involved in the cannibalistic activity.
Example- Black widow spider
- A form of cannibalism is observed in spiders where the female spider eats the male spider after coupling.
- It is a form of sexual cannibalism that is mostly facultative as this occurs only in dire situations.
- There are various theories regarding this interaction, but the most accepted explains that the female spider kills the male spider to obtain energy and nutrition to provide for the offspring.
References and Sources
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- <1% – https://www.independent.co.uk/life-style/health-and-families/features/tapeworms-cestodes-humans-symptoms-causes-treatment-avoid-infection-larvae-a6729991.html
- <1% – https://quizlet.com/40298337/adaptive-strategies-flash-cards/
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- <1% – https://en.wikipedia.org/wiki/Predator
- <1% – https://en.wikipedia.org/wiki/Cannibalism
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