Origins, Evolution, and Diversification of Zooplankton

Abstract

Fossil plankton are difficult to identify but have formed a major component of most marine ecosystems throughout geological time. The earliest fossil heterotrophs include planktic forms, and subsequent adaptive innovations quickly appeared in the plankton; these include metazoans and animals with hard parts. Movement into the plankton occurred sporadically throughout geological history and seems to have been independent of any biological or environmental forcing mechanism. Subsequent radiations and extinctions in the cohort of plankton closely reflect events in the benthos. The diversity of zooplankton rose quickly during the early Paleozoic era, but low plankton diversity characterized the late Paleozoic. Significant radiations during early Mesozoic times led to an overall increase in diversity through the Phanerozoic eon. As the composition of the zooplankton has changed, so has their effect on biogeochemical cycles.

The fossil record and palaeoenvironmental significance of marine arthropod zooplankton

“…This 399 has important potential implications for the evolutionary and ecological success of 400 many arthropod lineages, especially for groups where the larval stages and adults 401 have distinct ecologies, such as trilobites, barnacles and crabs. Neoteny of planktonic 402 larval stages has been considered to be a long established route into the plankton 403 (Rigby and Milsom, 2000). This could be the case, for example, for some trilobites 404 that had a planktonic larval stage (protaspid; Fig.…”

Lipids and life strategy of Arctic Calanus

“…Diatoms and copepods have evolved during a period of global cooling, largely since the K-T extinction event 65 million years ago, when polar ice caps were formed, and marine production in high latitudes became seasonally pulsed (Rigby & Milsom 2000). Kattner et al (2007) hypothesize that the present composition of the polar herbivore community in the Arctic, mainly consisting of the three Calanus species, as well as the development of highly efficient lipid synthesis of wax ester in these animals, is a consequence of the variations in climate observed over the past centuries and millennia.…”

Remarkable preservation of microbial mats in Neoproterozoic siliciclastic settings: Implications for Ediacaran taphonomic models

“…This elevated preservation potential is likely to have been further enhanced by the lack of zooplankton (e.g. Butterfield, 1997;Rigby & Milsom, 2000) or motile benthic scavengers and deposit feeders (e.g. Seilacher, 1999;Bottjer et al, 2000).…”