Taxonomic Aids And Diversity

Earth's vast biodiversity is emphasised in NCERT Class 11, Chapter 1 (The Living World), which notes that the number of species already described is well over a million, with animals, especially insects, forming the largest share. To answer this quantitatively, we apply the given proportion: 70 percent of the total 1.7 million described species are animals. Calculating, 0.70 multiplied by 1.7 million equals 1.19 million species, so approximately 1.19 million described animal species exist. The value of about 0.51 million is incorrect, as that represents the remaining 30 percent of non-animal species, obtained from 0.30 times 1.7 million. The figure of 1.70 million is wrong because that is the grand total of all described species, not the animal fraction alone. The value of 0.70 million mistakenly treats the percentage itself as an absolute count rather than applying it to the total. This overwhelming dominance reflects the extraordinary diversity of insects within the phylum Arthropoda, which alone account for more species than all other animal groups combined. A data-range sanity check confirms the result: 1.19 million is a sensible majority of 1.7 million and is fully consistent with the stated 70 percent share, validating the calculation.