Types of Aquatic Organisms - Freshwater Ecology: Concepts and Environmental Applications - page 115

FIGURE 7.2 Eichhornia azurea with different morphology of floating versus submersed
leaves within the same plant (courtesy of Steve Hamilton).
Thus, a large sample of individuals from different environmental condi-
tions is often useful to ensure correct identifications. Generally, systema-
tists that specialize in a specific group of organisms have clearly defined the
characteristics used to differentiate among distinct species.
The lack of a single system to define species that works well across all
taxonomic groups leads to a utilitarian species definition for those who are
not taxonomists: A species may be considered distinct if the majority of the
systematists studying the group of organisms agree that it is a distinct
species. This approach allows aquatic ecologists to use systematic data
without information about sexual reproduction of the species they are
studying or other complex methods of analysis. The taxonomic identity
can be communicated within the bounds of the best current scheme of
identification, providing a solid basis for ecological information. A reliable
scientific name can be used effectively in searching for biological informa-
tion on a species.