Animal-parasite: species and names
Every living organism adapts tosurrounding conditions and looking for the easiest ways for their existence. In the process of evolution, a species such as an animal parasite was formed. Parasitism is very developed in nature. He emerged from the usual symbiosis, when one living organism began to exist at the expense of another. Now from a huge number of animal species more than 6% refers to parasites. They can both cause great harm to the host's body, and to exist almost imperceptibly for him.
How did parasitism arise?
In a variety of relationships with each other allalive organisms. And not all of them lead to someone's death. In the course of evolution, relations have been developed that are useful to both sides or do no harm to them. What are the phenomena of symbiosis in nature?
- Mutualism is a form of relationships in which organisms can not exist without each other. For example, termites and their symbiotic flagella, living in their intestines.
- The protocol is beneficial for both parties, but it is not necessary. An example is the relationship of the fishes of the family of the Guban and moray eels, which they purify from parasites.
- Lodging is a kind of symbiosis, when one kind of animal uses another as shelter or asylum, without harming it. For example, the fish adhered to move with sharks.
- Nahlebnichestvo - a relationship in which one species eats the remains of the food of another. For example, ringed worms or jackals.
- But the most common relationship is competition, when the species compete with each other.
- From the previous type of relations appeared such,When one animal uses another for its own purposes, badly harming it at the same time. This predation is the eating of one individual by another and parasitism proper. These types of symbiosis are beneficial only to one side, and another organism suffers in one way or another.
Features of parasitism
Such relationships between different species, withwhich one organism exists at the expense of another, arose a very long time. Over the years of evolution, some species of animals have so adapted to parasitize that they can not live without the protection of the host. The animal parasite uses other organisms to obtain food, as places for the development of larvae, and very often - and as a permanent place of residence.
What animals are parasites?
The list of such organisms is quite large, but basically they all belong to several classes. Most often parasitize on others such animals:
- Protozoa that are so small that they can be confused with bacteria. These are the causative agents of toxoplasmosis, leishmaniasis, giardiasis, pyroplasmosis and other diseases in animals and humans.
- Flat and round worms are the mostcommon animal parasites. Examples of their names can be found everywhere. After all, they cause various helminthiases and are adapted to life only within the body of another animal or person. These include ascarids, various nematodes, pinworms, chains and many others.
"There are a lot of parasites among arthropods." Basically, they use the host to feed, for example, fleas and lice, but some live inside the body.
- Vertebrate animals are parasitessome cyclostomes, for example, lampreys, and bats. But their symbiosis is more like predation. In addition, nesting parasitism is common among some birds. It manifests itself in the fact that, for example, a cuckoo does not build nests, but lay its eggs to other birds.
Types of parasitism
Not all animal parasites use the host's body throughout their entire life. On this basis, they are distinguished by their types:
1. Temporary parasites - these are those that the entire development cycle is in the external environment. They use the host's body only to quench hunger. These insects are parasites of humans and animals: bedbugs, mosquitoes, horseflies, gadflies and others. Most often they are bloodsucking, and after eating, leave the host's body alone.
2. The stationary parasites live in the host organism throughout the course of their entire life. But such relationships are also periodic and permanent. Periodic parasitism is when the organism uses the host only in one stage of its development. For example, the gadfly parasitizes only as a larva, and the helminths - in most cases - in the sexually mature stage. An animal-parasite, which spends its entire life in the host's body, is called permanent. These are lice, scabies and some others.
Types of parasites in the place of life
Different species can parasitize both outside the host's body, on its skin and fur coat, and inside its body. On these grounds, two types are distinguished:
1. The most unpleasant for the owner are outdoor animal parasites. Their list is very impressive, and most of the warm-blooded animals, including humans, are familiar with most. Most of them are carriers of dangerous infectious diseases. These are various mites, fleas, lice, mosquitoes and others. They all also fall into several groups. Some of them only temporarily sit down on the host to take food, for example, mosquitoes. Others permanently live on the skin - lice, gnawing passages in the upper layer of the epidermis - itchy itch or sand flea, or choose as a residence different body cavities: nose, ear, eye or mouth. This, for example, larva of the gadfly.
2. Internal parasites, which permanently or temporarily reside in various organs of another animal, are also very numerous. But they are not so noticeable, although they can cause irreparable damage to the host's body. They can migrate inside the body and settle not only in the intestines, but also in muscles, blood cells and even in the brain. Thus, various protozoa and worms parasitize.
What are the hosts?
Most often distinguish two groups, whichthe organisms used by parasites are divided. These are obligatory and optional. Mandatory owners are those who are accustomed to parasites, and it is their organisms that are the most favorable environment for their life. The optional species are used by parasites for lack of the best. In addition, most parasitic organisms undergo several stages in their development. And often for each stage of his development he needs another master. For example, a malarial plasmodium uses a female mosquito and a human body. Biologists found that the intermediate host, in which the larva develops, is eaten by predators, and thus the parasite continues to develop. Larvae can enter the permanent host and through water or land.
Evolution of parasites
In the process of adapting to life within anotherorganism, parasitic species have acquired some features. Most of them atrophied organs of movement, and developed different suckers, hooks to hold on the body of the host. Blood-sucking species have special enzymes that dilute the blood of the victim and increase its inflow to the skin. Some parasites have lost their digestive functions and can, for example, suck food throughout the body, like some helminths. But those organisms that live inside the host had to develop protective mechanisms. For example, helminths produce anti- enzymes in order not to be digested by gastric juice. The organism of the parasite is simplified, but the function of reproduction in most cases is increased. And their larvae have special protective mechanisms that help them survive in an unfavorable environment.
What harm does the parasite inflict on the host?
Not always a symbiosis leads to the death of oneorganism. In most cases, it is beneficial for the parasite to have its owner survive. But the poisoning by products of exchange or destruction of tissues most often leads to illness and death of the individual. Insects, parasites of animals, do the least harm. But the constant itch from the presence of ticks or lice, damage to the coat or feathers in birds leads to a decrease in working capacity and greater availability of the individual to predators.
Animals-parasites of plants
Some species parasitize not only the livingorganisms, but also on plants. They suck nutrients out of them. Most often this leads to the death of the plant. To such types of parasites belong many nematodes living in the roots, as well as a large number of insects: aphids, mites, mollusks, butterflies and many others. They can parasitize on leaves and stems, attaching to them or moving from place to place.
