Biological Evolutionary Lineages in Marine Habitats of the Phanerozoic

General characteristics of marine habitats are hard to imagine. High unpredictable three-dimensional dynamics, reduced influences of gravity, or prevalent microbial primary production are far from terrestrial experiences. Without static barriers are oceans separated into different habitats by hydrodynamics and variable combinations of essential environmental factors, e.g. light or nutrients. Photosynthetic primary production is restricted to irradiated surface zones. Additional chemoautotrophic primary production is concentrated on scattered benthic hydrothermal vents. Biomass production of plankton is characterised by short-term events of high irregular dynamics. Several microorganisms can compensate irregularities of environmental conditions by switching between photoautotrophic and heterotrophic metabolism (mixotrophy). In oceans is embodied energy dominantly stored in consumers by fast transfers within food webs up to the largest vertebrates. Survival of animals beyond photic zones is only possible by consumption of dead or living organic matter. Resulting interactions within animal food webs stimulated the evolution of basic life forms and survival strategies of metazoa from sessile sponges to octopuses or fast-moving sharks and bonefishes. Sessile and reef building animals—for example corals—provide a huge variety of structured habitats for mobile animals. Still limited is knowledge about bioluminescent organisms in dark pelagic zones and ecological processes in the deep sea. However, macroevolution in oceans demonstrates limits of eco-morphological differentiation within a specific set of physical framework conditions, proved by repeated returns of terrestrial vertebrate life forms—reptilians, birds and mammals into functional gaps of aquatic ecosystems.