Species diversity

Species diversity is a measure of the number and frequency of species in a community. Biodiversity is most commonly described in terms of species diversity, and particularly in terms of species richness (the number of species in a given habitat). In the ocean, there is a plenty of information on marine mammals (seals, whales, dolphins, porpoises) and fish, while only recently are scientists beginning to understand the extreme diversity present in micro-organisms such as bacteria and phytoplankton.

This is the common definition for Species diversity, other definitions can be discussed in the article