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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]
Normal probability plots are made of raw data, residuals from model fits, and estimated parameters. A normal probability plot. In a normal probability plot (also called a "normal plot"), the sorted data are plotted vs. values selected to make the resulting image look close to a straight line if the data are approximately normally distributed.
The simplest case of a normal distribution is known as the standard normal distribution or unit normal distribution. This is a special case when μ = 0 {\textstyle \mu =0} and σ 2 = 1 {\textstyle \sigma ^{2}=1} , and it is described by this probability density function (or density): φ ( z ) = e − z 2 2 2 π . {\displaystyle \varphi (z ...
No longer regarded as a major extinction but rather a series of lesser events due to bolide impacts, eruptions of flood basalts, climate change and disruptions to oceanic systems [16] Pliensbachian-Toarcian extinction (Toarcian turnover) 186-178 Ma: Formation of the Karoo-Ferrar Igneous Provinces [17] Triassic: Triassic–Jurassic extinction ...
For example, in an article published in 2004, Otso Ovaskainen and Ilkka Hanski explained with an empirical example that when factors such as Allee effect or Rescue effect were included in modeling the extinction threshold, there were unexpected extinctions in a high number of species. A more complex model came up with different results, and in ...
[47] [48] For example, coral reefs—which are biodiversity hotspots—will be lost by the year 2100 if global warming continues at the current rate. [49] [50] Still, it is the general habitat destruction (often for expansion of agriculture), not climate change, that is currently the bigger driver of biodiversity loss.
The surviving populations are in continual decline in 43% of those that are threatened. Since the mid-1980s the actual rates of extinction have exceeded 211 times rates measured from the fossil record. [148] However, "The current amphibian extinction rate may range from 25,039 to 45,474 times the background extinction rate for amphibians."
Red list categories of the IUCN Demonstrator against biodiversity loss, at Extinction Rebellion (2018).. The current rate of global biodiversity loss is estimated to be 100 to 1000 times higher than the (naturally occurring) background extinction rate, faster than at any other time in human history, [25] [26] and is expected to grow in the upcoming years.