Dancing to the rhythms of geological time: the biorhythm capabilities of Polychaeta in a geological context

P J W Olive, C P Kyriacou, Kim Last,

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

Errant polychaete worms in the Orders Eunicida (family Eunicidae) and Phyllodocida (families Nereidae and Polynoidae) exhibit a highly developed biorhythmic capability. The Pacific palolo worms are well known for a precisely timed annual breeding event in which mass spawning occurs at a particular time of day, on one day per year, that day having a fixed relationship to the lunar period. Nereidae and Polynoidae exhibit photoperiodic responses that determine the breeding season by regulation of oocyte growth. Nereis virens shows short-term cycles of foraging activity; automated recording of these patterns has revealed four distinct behaviour rhythm phenotypes: circadian, tidal, lunidian and arrhythmic, the last phenotype being expressed during the photoperiod induced growth diapause. The Eunicids and Phyllodocids are represented in the fossil record by scolecodonts, their fossilised jaws. There was a major radiation of these polychaetes during the Ordovician and the earliest suggested polychaete fossils are from the Cambrian. The simultaneous expression of tidal and circadian rhythmicity is characteristic of intertidal animals and it is likely that this complex behavioural repertoire was found in the ancestors of modem terrestrial forms, such as tetrapods and arthropods, prior to their emergence onto land during the Carboniferous and Silurian periods at least 400 Ma. The period of the earth's rotation, and hence day length and tidal period, has long been known to be increasing, and additionally the moon to be retreating from the earth, due to the phenomenon of tidal friction caused by the gravitational interactions between the moon and the earth These changes are significant over a geological time scale. Consequently, the length of day was substantially less (and the number of days in a year more) than at present in the Cambrian and Ordovician periods. Recent theoretical analysis of the period of the earth's rotation suggests that the day length prior to a critical period (t(crit)) around 1800 Ma may have been stable, with a length of only 4 h. At that time a period of more rapid change in the dynamics of the rotation was initiated. The implications of this theory for the evolution of the biological clock are discussed.
Original languageEnglish
Pages (from-to)197-206
Number of pages10
JournalINVERTEBR REPROD DEV
Volume48
Issue number1-3
Publication statusPublished - 2005

    Fingerprint

Keywords

  • ARENICOLA-MARINA
  • HARMOTHOE-IMBRICATA L
  • Zoology
  • Reproductive Biology
  • SEASONAL REPRODUCTION
  • NEREIS NEANTHES VIRENS
  • ENVIRONMENTAL-TEMPERATURE
  • EUNICE-VIRIDIS POLYCHAETA
  • BENTHIC POLYCHAETE
  • EARTH-MOON SYSTEM
  • LOCOMOTOR-ACTIVITY
  • CIRCADIAN-RHYTHMS

Cite this