BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Algal Phototaxis and the Evolution of Multicellularity - Raymond G
 oldstein (University of Cambridge)
DTSTART:20231023T100000Z
DTEND:20231023T110000Z
UID:TALK206128@talks.cam.ac.uk
DESCRIPTION:A fundamental issue in biology is the nature of evolutionary t
 ransitions from unicellular to multicellular organisms. Volvocine algae&nb
 sp\;are&nbsp\;\nmodels for this transition\, as they span from the unicell
 ular biflagellate&nbsp\;Chlamydomonas&nbsp\;to multicellular species of&nb
 sp\;Volvox&nbsp\;with up to&nbsp\;\n50\,000&nbsp\;Chlamydomonas-like cells
  on the surface of a spherical extracellular matrix. The mechanism of phot
 otaxis in&nbsp\;these species is&nbsp\;\nof particular interest since they
  lack a nervous system and intercellular connections\; steering is a conse
 quence of&nbsp\;the response of individual&nbsp\;\ncells to light. In this
  talk I will describe experimental and theoretical work on the mechanism o
 f phototaxis&nbsp\;in three members of the Volvocine&nbsp\;\nalgae\, spann
 ing 3 orders of magnitude in cell number. We find that there is an evoluti
 onarily&nbsp\;conserved dynamics\, with a tuning between&nbsp\;\nthe time 
 scales for an adaptive flagellar response to changing light levels illumin
 ating&nbsp\;the photoreceptors and the spinning frequencies of the&nbsp\;\
 nmicroorganisms. The implication of these results for the evolution of mul
 ticellularity&nbsp\;are discussed.
LOCATION:Seminar Room 1\, Newton Institute
END:VEVENT
END:VCALENDAR