origin of multicellular plants

On Wed, 17 Mar 2004 15:57:11 +0000 (UTC), [email hidden]

(Daniel Sch?tz) said:

Dear NG,

in zoology there are a lot of evolution models for the
origin of multicellularity. But is there any model for the
origin of multicellularity in botany, too? What? How does
it think about? I've you do know, please contact me or
write in this NG.

All models of multicellularity stem from models in the
Protista. There are numerous algae (brown, red, and green)
with true multicellularity. In particular, the green algae
represent the origin of the multicellular plants (they
share chlorophyll-b, cellulose cell walls, starch storage).
The charophyceans in particular seem to be the origin of
the plants.

Green algae include single celled forms, forms made of two
cells or small clumps of cells, long filaments, sheets, and
globular clusters. Look up the "Volvocine series" in google
for examples of what is traditionally considered one model
for the evolution of multicellularity. Check out

Kirk D. (1999) "Evolution of multicellularity in the
volvocine algae", Current Opinion in Plant Biology, 2 :
496-501

Abstract: Recent studies reveal that relationships among the
volvocine algae are more complex than was previously
believed. Nevertheless, this group still appears to provide
an unrivaled opportunity to analyze an evolutionary pathway
leading from unicellularity (Chlamydomonas) to
multicellularity with division of labor (Volvox).
Significant progress in this regard was made in the past
year when two genes playing key roles in Volvox cellular
differentiation were cloned, and clues were uncovered
regarding their mechanisms of action.

I can't find a free copy of this on the web.

For some general thoughts on the subject, not restricted to
plants, see

PNAS paper by Pfieffer and Bonhoeffer, "An evolutionary
scenario for the transition to undifferentiated
multicellularity" at genetics.med.harvard.edu~dsegrOpen ↗
e/Pfeiffer_Bonhoeffer_PNAS_2003_multicell.pdf

Heredity paper by Michod and Roze, "Cooperation and conflict
in the evolution of multicellularity" at eebweb.ariz-eebweb.ariz-Open ↗
ona.edu/Michod/Downloads/Cooperation%20and%20conflict%20Her-
edity%20paper.pdf

On Wed, 17 Mar 2004 15:57:11 +0000 (UTC), [email hidden]

(Daniel Sch?tz) said:

Dear NG,

in zoology there are a lot of evolution models for the
origin of multicellularity. But is there any model for the
origin of multicellularity in botany, too? What? How does
it think about? I've you do know, please contact me or
write in this NG.

Yours sincerely

Daniel

For starters read _First Signals: The evolution of
multicellular development_ by John Tyler Bonner. Find it on
amazon.com

dunk