Life cycle

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Fig. 1. Standard dimorphic or trimorphic reproductive cycle in benthic, medium- to large-sized foraminifera according to Goldstein, 1999. Schizogeny, eventually repeated several times, may be widespread in larger foraminifera from oligotrophic habitats. Planktic foraminifera seem to have no dimorphic life cycle. Life cycles are linked in various ways to seasonal cycles. Example: Heterostegina depressa d'Orbigny, equatorial sections, Gulf of Aqaba, Red Sea (from Hottinger, 1977); (Hottinger, 2006; fig. 5 [1] CC/BY-NC-SA)

Definition

  • according to Hottinger (2006):

LIFE CYCLE- most eucariotic, free-living cells reproduce asexually but shift from time to time to sexual reproduction in order to avoid degeneration (Muller's ratchet, 1964). In many foraminifera the alternation of sexually and asexually produced generations is documented in the morphology of the shell by dimorphism or trimorphism. In foraminifera, there are many different types of life-cycles (Lee et alii, 1991; Goldstein, 1999). They differ in particular by the position of the nuclear reduction division (abbreviated R!) within the cycle. Planktic foraminifera are interpreted as reproducing exclusively by sexual processes.

See also

References

Hottinger (1977), Foraminifères operculiniformes. Mémoires du Muséum National d'Histoire Naturelle, Paris, (Série C, Sciences de la terre), t. XL, 159 p. + 66 pls.

Goldstein (1999), Foraminifera, a biological overview. In: Sen Gupta B.K. (ed.), Modern Foraminifera, Kluwer Academic Publishers, Dortrecht, p. 37-55.

Hottinger (2006), Illustrated glossary of terms used in foraminiferal research. Carnets de Géologie, Memoir 2, ISSN 1634-0744

Lee, Faber, Anderson & Pawlowski (1991), Life cycle in Foraminifera. In: Lee J.J & O.R. Anderson (eds.): Biology of the Foraminifera, Academic Press, London, p. 285–343.

Muller (1964), The relation of recombination to mutational advance, Mutation Research, Amsterdam, vol. 1, N° 1, p. 2-9.

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