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In many cases, the values given for "Described" species are an estimate only (sometimes a mean of reported figures in the literature) since for many of the larger groups in particular, comprehensive lists of valid species names do not currently exist. For fossil species, exact or even approximate numbers are harder to find; Raup, 1986 [15 ...
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]
Over 1.5 million living animal species have been described—of which around 1 million are insects—but it has been estimated there are over 7 million in total. Animals range in size from 8.5 millionths of a metre to 33.6 metres (110 ft) long and have complex interactions with each other and their environments, forming intricate food webs .
there is no easy way to tell whether related geographic or temporal forms belong to the same or different species. Species gaps can be verified only locally and at a point of time. One is forced to admit that Darwin's insight is correct: any local reality or integrity of species is greatly reduced over large geographic ranges and time periods. [19]
The order Primates consists of 505 extant species belonging to 81 genera. This does not include hybrid species or extinct prehistoric species. Modern molecular studies indicate that the 81 genera can be grouped into 16 families; these families are divided between two named suborders and are grouped in those suborders into named clades, and some of these families are subdivided into named ...
It is estimated that more than 99% of all species that ever existed on Earth, amounting to over five billion species, [3] are extinct. [4] [5] Earth is the only celestial body known to harbor life forms. No form of extraterrestrial life has yet been discovered. [6]
Over 1.5 million living animal species have been described, of which around 1.05 million are insects, over 85,000 are molluscs, and around 65,000 are vertebrates. It has been estimated there are as many as 7.77 million animal species on Earth. Animal body lengths range from 8.5 μm (0.00033 in) to 33.6 m (110 ft).
A few polyploid species as for example D. glochidiatus (2n = 4x = 44) and D. montanus (2n = 6x = 66) also exist. [30] [30] 34 Cabbage (Brassica oleracea) 18 Broccoli, cabbage, kale, kohlrabi, brussels sprouts, and cauliflower are all the same species and have the same chromosome number. [22]: 49 [22]: 49 35 Citrus (Citrus) 18