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A May 2016 study based on scaling laws estimated that 1 trillion species (overwhelmingly microbes) are on Earth currently with only one-thousandth of one percent described, [28] [29] though this has been controversial and a 2019 study of varied environmental samples of 16S ribosomal RNA estimated that there exist 0.8-1.6 million species of ...
More than 99 percent of all species, amounting to over five billion species, [7] that ever lived on Earth are estimated to be extinct. [8] [9] Estimates on the number of Earth's current species range from 10 million to 14 million, [10] of which about 1.2 million have been documented and over 86 percent have not yet been described. [11]
Many of the constants have been derived from reaction of so-called benzhydrylium ions as the electrophiles: [10] and a diverse collection of π-nucleophiles: . Typical E values are +6.2 for R = chlorine, +5.90 for R = hydrogen, 0 for R = methoxy and −7.02 for R = dimethylamine.
[2] [3] Estimates on the number of Earth's current species range from 10 million to 14 million, [4] with about 1.2 million or 14% documented, the rest not yet described. [5] However, a 2016 report estimates an additional 1 trillion microbial species, with only 0.001% described. [6]
The list of organisms by chromosome count describes ploidy or numbers of chromosomes in the cells of various plants, animals, protists, and other living organisms.This number, along with the visual appearance of the chromosome, is known as the karyotype, [1] [2] [3] and can be found by looking at the chromosomes through a microscope.
[6] [7] When inbreeding effects are included, estimates of MVP for many species are in the thousands. Based on a meta-analysis of reported values in the literature for many species, Traill et al. reported concerning vertebrates "a cross-species frequency distribution of MVP with a median of 4169 individuals (95% CI = 3577–5129)."
In 1962, Edwards and Pearson (the latter of HSAB theory) introduced the phrase alpha effect for this anomaly. He offered the suggestion that the effect was caused by a transition state (TS) stabilization effect: on entering the TS the free electron pair on the nucleophile moves away from the nucleus, causing a partial positive charge which can be stabilized by an adjacent lone pair as for ...
For many years, exobiologists have proposed the existence of a shadow biosphere, a postulated microbial biosphere of Earth that uses radically different biochemical and molecular processes than currently known life.