| Popis: |
An overview of marine invertebrate biodiversity is complicated because there are two distinct marine domains, the open ocean and the seafloor, which are affected by different ecological processes. The physical characteristics of the world ocean are described here both from the viewpoint of a benthic scientist who studies the animals that live on the seabed and a pelagic scientist who studies the organisms that float or swim freely in the water. The pelagic sections include some consideration of single-celled organisms, including examples capable of photosynthesis, because excluding them would be artificial. The processes that produce modern marine diversity patterns are described and the unique features that make marine diversity different from terrestrial diversity are listed. By convention, both pelagic and benthic fauna are not categorized by a functional ecological approach but by the type of equipment used to sample the organisms, which largely depends on their size. The different size classes are listed and examples given of the organisms included in each group. A major limitation in understanding marine invertebrate biodiversity is the inadequate state of taxonomic knowledge of marine organisms, particularly the small and deep-sea taxa. The implications of our ignorance for estimating regional or global diversity are discussed. Open ocean pelagic biogeography patterns are described and examples given of species with commonly occurring patterns. Benthic diversity patterns are divided into large and small scale. The large-scale patterns include latitudinal and bathymetric gradients. The change in both diversity and the dominant faunal groups over evolutionary time from the Cambrian to the present is followed. Finally, the unusual hydrothermal and cold seep fauna that have been recently discovered are described. |
