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The Red List Index (sampled approach) (SRLI) has been developed in order to determine the threat status and also trends of lesser-known and less charismatic species groups. It is a collaboration between IUCN members and is coordinated through the Institute of Zoology (IoZ), the research division of the Zoological Society of London (ZSL).
This is a list of extinction events, both mass and minor: [1] ... It does not represent all marine species, just those that are readily fossilized.
As these data are derived at the genus level, one can anticipate that the number of species extinctions is a higher percentage than shown here. Many of the extinction events appear to be somewhat extended in time. In at least some cases this is the result of a paleontological artifact known as the Signor-Lipps effect (Signor & Lipps 1982).
Background extinction rates are typically measured in order to give a specific classification to a species and this is obtained over a certain period of time. There are three different ways to calculate background extinction rate. [5] The first is simply the number of species that normally go extinct over a given period of time.
A 2008 study, published in the journal Nature, established a relationship between the speed of mass extinction events and changes in sea level and sediment. [142] The study suggests changes in ocean environments related to sea level exert a driving influence on rates of extinction, and generally determine the composition of life in the oceans ...
The following list is incomplete by necessity, since the majority of extinctions are thought to be undocumented, and for many others there isn't a definitive, widely accepted last, or most recent record. According to the species-area theory, the present rate of extinction may be up to 140,000 species per year. [1]
Diversification rates can be estimated time-series data on fossil occurrences. With perfect data, this would be an easy task; one could just count the number of speciation and extinction events in a given time interval, and then use these data to calculate per-lineage rates of speciation and extinction per unit time.
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.