Taxa: In biology, a taxon (back-formation from taxonomy; plural taxa) is a group of one or more populations of an organism or organisms seen by taxonomists to form a unit.
- Flora: It is all the plant life present in a particular region or time, generally the naturally occurring (indigenous) native plants. Sometimes bacteria and fungi are also referredto as flora.
- Fauna: It is all of the animal life present in a particular region or time.
- Invertebrate: They are species of animal that neither possess nor develop a vertebral column (commonly known as a backbone or spine), derived from the notochord. The IUCN estimates that 66,178 extant vertebrate species have been described which means that over 95% of the described animal species in the world are invertebrates; Estimated number of described species (approx. 1,300,000- Insects (1,000,00), Arachnids (102,248), Molluscs (85,000), Crustaceans (47,000) and others (71,002)(The World Conservation Union 2004).
- Vertebrate: They comprise all species of animals within the subphylum Vertebrata (chordates with backbones), including all fishes, amphibians, reptiles, birds and mammals. Vertebrates represent the overwhelming majority of the Phylum Chordata, with currently about 69,963 species described. The IUCN estimates that 1,305,075 extant invertebrate species have been described which means that less than 5% of the described animal species in the world are vertebrates. Estimated number of described species (66,178) – Fishes (>32,000), Amphibians (7,302), Reptiles (10, 711), Birds (10, 425) and Mammals (5, 513) (The World Conservation Union 2004; Nelson 2016).
In Nepal, a total of 173 threatened species are recorded. Whereas Flora (6) and Fauna (168) : Invertebrate (4), Fishes (42), Amphibians (10), Reptiles (30), Birds (37) and Mammals (44).