|
Overpopulation is a scenario in which the population of a living species exceeds the carrying capacity of its ecological niche. While this term is most often used with reference to human beings, in its general form it includes overpopulation in any animal or vegetal species. Carrying capacity is the population level that can be supported for an organism, given the quantity of food, habitat, water and other life infrastructure present. ...
Two lichenes species on a rock, in two different ecological niches In ecology, a niche is a term describing the relational position of a species or population in an ecosystem. ...
Map of countries by population —showing the population of the China and India in the billions. ...
Overpopulation is not a function of the number or density of the individuals, but rather the number of individuals compared to the resources they need to survive. In other words, it is a ratio: population over resources. These resources include primarily drinking water and food, which also imply essential nutrients of the appropriate type, and suitable food sources for the species.
Besides the issue of overpopulation in wild species, human beings have introduced a different problem: that of artificially constructed populations (domestic pets, cattle, agriculture, etc.)
Wild animal overpopulation
In the wilderness, the problem of animal overpopulation is solved by predators. Predators tend to look for signs of weakness in their prey, and therefore usually first eat the old or sick animals. This has the side effects of insuring a strong stock among the survivors, and controlling the population. This snapping turtle is trying to make a meal of a Canada goose, but the goose is too wary. ...
In the absence of predators, animal species are bound by the resources they can find in their environment, but this does not necessarily control overpopulation. In fact, an abundant supply of resources can produce a population boom that ends up with more individuals than the environment can support. In this case, starvation, thirst and sometimes violent competition for scarce resources may effect a sharp reduction in population in a very short lapse (a population crash). Lemmings, as well as other less popular species of rodents, are known to have such cycles of rapid population growth and subsequent decrease. Genera Dicrostonyx Lemmus Synaptomys Myopus * Incomplete listing: see vole Lemmings are small rodents, usually found in or near the Arctic. ...
Suborders Sciuromorpha Castorimorpha Myomorpha Anomaluromorpha Hystricomorpha Rodentia is an order of mammals also known as rodents. ...
Some animal species seem to have a measure of self-control, by which individuals refrain from mating when they find themselves in a crowded environment. This voluntary abstinence may be induced by stress or by pheromones. Fanning honeybee exposes Nasonov gland (white-at tip of abdomen) releasing pheromone to entice swarm into an empty hive A pheromone is any chemical or set of chemicals produced by a living organism that transmits a message to other members of the same species. ...
In an ideal setting, when animal populations grow, so do the number of predators that feed on that particular animal. Animals that have birth defects or weak genes (such as the runt of the litter) also die off, unable to compete over food with stronger, healthier animals. A congenital disorder is a medical condition or defect that is present at or before birth (for example, congenital heart disease). ...
This stylistic schematic diagram shows a gene in relation to the double helix structure of DNA and to a chromosome (right). ...
In reality, an animal that is not native to an environment may have advantages over the native ones, such being unsuitable for the local predators. If left uncontrolled, such an animal can quickly overpopulate and ultimately destroy its environment.
Examples of animal overpopulation caused by introduction of a foreign species abound.
- In the Argentine Patagonia, for example, European species such as the trout and the deer were introduced into the local streams and forests, respectively, and quickly became a plague, competing with and sometimes driving away the local species of fish and ruminants.
- In Australia, when rabbits were introduced (unwillingly) by European immigrants, they bred out of control and ate the plants that other native animals needed to survive. Farmers hunted the rabbits to reduce their population and prevent the damage the rabbits did to the crops. They also brought cats to guard against rabbits and rats. These cats created another problem, since they became predators of local species.
In orange the area most commonly defined as Patagonia. ...
Rainbow trout, Oncorhynchus mykiss Biwa trout, Oncorhynchus masou subsp Trout is the common name given to a number of species of freshwater fish belonging to the salmon family, Salmonidae. ...
Subfamilies Odocoilinae Cervinae Hydropotinae Muntiacinae A deer is a ruminant mammal belonging to the family Cervidae. ...
Families Antilocapridae Bovidae Cervidae Giraffidae Moschidae Tragulidae A ruminant is any hooved animal that digests its food in two steps, first by eating the raw material and regurgitating a semi-digested form known as cud, then eating the cud, a process called ruminating. ...
Pet overpopulation A different overpopulation concern pertains to the population growth of domestic cats and dogs. In the United States alone, between 3 and 4 million cats and dogs are euthanized each year for lack of homes to adopt them, according to the Humane Society of the United States.[1] As a result, most humane societies, animal shelters and rescue groups urge pet owners to have their pets spayed or neutered to prevent the births of unwanted and accidental litters. Trinomial name Felis silvestris catus (Linnaeus, 1758) The cat (or domestic cat, house cat) is a small domesticated carnivorous mammal. ...
Trinomial name Canis lupus familiaris The dog is a mammal in the order Carnivora. ...
A humane society is a group that aims to stop animal and human suffering due to cruelty or other reasons. ...
Dog at a no-kill animal shelter in Washington, Iowa An animal shelter is a facility that houses homeless, lost or abandoned animals; primarily dogs and cats. ...
A rescue group or rescue organization takes unwanted or abused pets and attempts to find new, caring homes for them. ...
Spaying and neutering are the respective processes of female and male animal sterilization, in order to keep them from producing offspring. ...
Pet overpopulation can be an ecological concern as well as a concern over animal welfare, with overpopulation occurring when there are more domestic cats and dogs than there are people wanting them as pets, independent of ecological carrying capacity. It is also a financial problem: Capturing, impounding and eventual euthanasia costs taxpayers and private agencies millions of dollars each year, according to the American Veterinary Medical Association.[2] Euthanasia (Greek, good death) is the practice of killing in a painless or minimally painful way for merciful reasons, usually to end suffering. ...
Although the term overpopulation is a generic term, true overpopulation means that there are actually more pets available than there are homes available. If one examines the numbers of homes which are seeking pets (as an example) and finds that 100 of those homes want pets which are, say, 1yr old and of a pure breed under 25 pounds, then to say that overpopulation exists simply because not all of the animals in a shelter will meet the desired criteria (1yr old/purebred under 25lb) is not exactly overpopulation. The fact that some shelters elect to kill animals is not necessarily indicative of overpopulation, as there is no standard for shelters reporting, tabulating, counting or categorizing their numbers/stats nationwide; in fact, it is not even known exactly how many animal shelters exist in the United States.
Overpopulation, then, is often used generically to refer to those pets that are not finding homes for reasons such as breed, temperament, age, health, or size. It does not necessarily mean there is no owner who desires a pet, but that there is no owner found which necessarily wants that particular animal at that time.
Sources and external links |
Feeds |
Contact