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Extinctions are a normal part of the evolutionary process, and the background extinction rate is a measurement of "how often" they naturally occur. Normal extinction rates are often used as a comparison to present day extinction rates, to illustrate the higher frequency of extinction today than in all periods of non-extinction events before it. [1]
Operant extinction differs from forgetting in that the latter refers to a decrease in the strength of a behavior over time when it has not been emitted. [6] For example, a child who climbs under his desk, a response which has been reinforced by attention, is subsequently ignored until the attention-seeking behavior no longer
More significantly, the current rate of global species extinctions is estimated as 100 to 1,000 times "background" rates (the average extinction rates in the evolutionary time scale of planet Earth), [71] [72] faster than at any other time in human history, [73] [74] while future rates are likely 10,000 times higher. [72]
This is much faster than the expected “background” extinction rate, or the rate at which species would naturally die off without outside influence — in the absence of human beings, these 73 ...
Humans are the main cause of the current mass extinction, called the Holocene extinction, driving extinctions to 100 to 1000 times the normal background rate. [ 120 ] [ 121 ] Though most experts agree that human beings have accelerated the rate of species extinction, some scholars have postulated without humans, the biodiversity of the Earth ...
"Behavioral sink" is a term invented by ethologist John B. Calhoun to describe a collapse in behavior that can result from overpopulation.The term and concept derive from a series of over-population experiments Calhoun conducted on Norway rats between 1958 and 1962. [1]
For example, if λ is 0.6 and μ 0.55 (both measured in rates per species per million years), the initial rate of species production would be 1.2 (2λ); but if they were 0.15 and 0.1 respectively, the initial rate would only be 0.3, even though the overall diversification rate is the same in both cases, 0.05. it can be seen that the initial ...
There are also several instances of predators and scavengers dying out or becoming rarer following the disappearance of species which represented their source of food: for example, the coextinction of the Haast's eagle with the moa, or the near-extinction of the California condor after the extinctions of its primary food, the dead carcasses of ...