7 - Types of Aquatic Organisms

Abstract

This chapter provides basic taxonomic principles, introduces different ways to classify organisms, outlines how they survive and their habitats, and introduces some essential terminology related to habitat and species interactions. Traditional taxonomic schemes have distinguished among organisms using behavior, metabolic characteristics, and morphology. Recently, molecular techniques have been used. Bacteria and Archaea are two groups with the greatest amount of metabolic diversity. Organisms can also be classified by their mode of obtaining nutrition and by the habitat they inhabit in addition to their evolutionary relatedness. Organisms can be classified by their direct interactions (competition, mutualism, exploitation, commensalism, amensalism, and neutralism) with other organisms. Freshwater habitats contain representatives of many of the groups of organisms on Earth. All major phyla of invertebrates, with the exception of the Echinodermata, have some freshwater species. As with vertebrates, many plants in aquatic systems have been well characterized.