Biodiversity is a system in constant evolution, from a viewpoint of species, as well as from viewpoint of an individual organism. Species Diversity is types of Diversity. This refers to the variety of species. It relates to the number of species in a defined area. The diversity of species can be measured through its richness, abundance, and types. Some areas are richer in species than others. Areas rich in species diversity are called hotspots of diversity.
A species can be defined as a group or population of related organisms that reproduce by interbreeding within the group. Members of a species do not normally reproduce with members of any other species. Members of an exact species possess regular characteristics that distinguish them from other species and this remains constant regardless of geographic location. Human beings, for example, belong to a single species — Homo sapiens and can effectively breed with different human populations around the world because they all belong to the same species.
Examples include all the species on Earth, ranging from plants such as bacteria, viruses, fungi, algae, bryophytes, pteridophytes, gymnosperms, angiosperms and all the species of animals including unicellular protozoans to mammals.