Title: A
twelve-step program for evolving multicellularity and
a division of labor
Author(s): Kirk DL
Source: BIOESSAYS 27
(3): 299-310 MAR 2005
Abstract: The volvocine algae
provide an unrivalled opportunity to explore details of an evolutionary pathway
leading from a unicellular ancestor to multicellular
organisms with a division of labor between different cell types. Members of
this monophyletic group of green flagellates range in complexity from
unicellular Chlamydomonas through a series of extant
organisms of intermediate size and complexity to Volvox,
a genus of spherical organisms that have thousands of cells and a germ-soma
division of labor. It is estimated that these organisms all shared a common
ancestor about 50 +/- 20 MYA. Here we outline twelve important ways in which
the developmental repertoire of an ancestral unicell
similar to modern C. reinhardtii was modified to
produce first a small colonial organism like Gonium that was capable of
swimming directionally, then a sequence of larger organisms (such as Pandorina, Eudorina and Pleodorina) in which there was an increasing
tendency to differentiate two cell types, and eventually Volvox
carteri with its complete germ-soma division of labor.
Title: The
occurrence of a bloom-forming green alga Pleodorina
indica (Volvocales) in the
downstream reach of the River Malse (
Author(s): Znachor P, Jezberova J
Source: HYDROBIOLOGIA
541: 221-228
Abstract: In
mid-August 2003 a massive bloom of the green alga Pleodorina
indica (Iyengar) Nozaki (Volvocales) occurred in the downstream reach of the River Malse in the