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The Devils Hole pupfish (Cyprinodon diabolis) is a critically endangered species of the family Cyprinodontidae (pupfishes) found only in Devils Hole, a water-filled cavern in the US state of Nevada. It was first described as a species in 1930 and is most closely related to C. nevadensis and the Death Valley pupfish ( C. salinus ).
The Devils Hole pupfish reached a 25-year high spring count of 191 fish. For years, the fish’s population dwindled, hitting an “all-time low of 35 in 2013,” the National Park Service said in ...
Thomas Robert Malthus, after whom Malthusianism is named. Malthusianism is a theory that population growth is potentially exponential, according to the Malthusian growth model, while the growth of the food supply or other resources is linear, which eventually reduces living standards to the point of triggering a population decline.
Malthus wrote that all life forms, including humans, have a propensity to exponential population growth when resources are abundant but that actual growth is limited by available resources: "Through the animal and vegetable kingdoms, nature has scattered the seeds of life abroad with the most profuse and liberal hand. ...
Before the mid-1990s, scientists counted between 200 and 250 Devils Hole pupfish each spring. But over the course of about 20 years, the fish's population count dropped to an average of about 90 ...
Devils Hole is a geologic formation located in a detached unit of Death Valley National Park and surrounded by the Ash Meadows National Wildlife Refuge, in Nye County, Nevada, in the Southwestern United States. Devils Hole is habitat for the only naturally occurring population of the endangered Devils Hole pupfish (Cyprinodon diabolis).
Malthus also notes that the checks on the human population are more complicated than those on animals and plants. [25] Malthus explains, for example, that a human check on population growth is the conscious decision not to reproduce because of financial burden. [25] Malthus then explains that the main check on population growth is food.
He describes the struggle resulting from population growth: "It is the doctrine of Malthus applied with manifold force to the whole animal and vegetable kingdoms." He discusses checks to such increase including complex ecological interdependencies, and notes that competition is most severe between closely related forms "which fill nearly the ...