, the Amazonian rain forest exhibits the greatest biodiversity on earth with the following estimated species counts: invertebrates (> 1,25,000), plants (> 40,000), fishes (3,000), birds (1,300), mammals (427), and amphibians (427). Assigning these to the labels commonly used in this context—(a) plants, (b) invertebrates, (c) fishes, (d) mammals, and (e) birds—the descending order by population size is (b) > (a) > (c) > (e) > (d).