1. INTRODUCTION
5
must be some way to characterize and compare these forms quantitatively.... Fig. a.ja-n. A phylogenetic overview of
Comparing the shapes of organisms without looking at the finer biological
seaweeds, . sp onge~, and corals: A.. didetails might seem a rather academical exercise however in palaeontology in agrammatic drawings of stromatolites:
c
.. d
. . . '. . .
(a) Baicaliform (b) Gymnosoleniform
many cases only a fossilize macroscopic rorrn is available without any finer () T
·C ' (ft H ff
6)'
c ungussllorm a er 0 man, i97 ;
structures for further study.
B. red seaweeds (Rhodophyta), coralline
In this book we want to show that in addition to field (in vivo) and laboalgae: (d) and (e) (growth forms of
ratory (in vitro) approaches, there is another option for the study of growth
Lithothamnion calcareum), red seaand form in marine sessile organisms. That is by using simulation modw~eds (Rhodophyta): if) Chondrus
els (the "in silica" option). Development of practical simulation models of CrlSpUS; C. ?rown ~eaweeds (Phaeo.
.
.
.
phyta): (g) Dictyota dichotoma: D. green
the growth and development of manne sessile organisms is now both posseaweeds (Chlorophyta): (h) C~dium tosible and important. It is possible because their growth process is relatively mentosum (all seaweeds after Newton
simple and with the enormous progress that has been made toward under- 1931); E. sponges: (i) demosponge Halstanding the basic developmental mechanisms of model organisms, we might
iclona oculata (after Bowerbank 1876),
expect to find some basic mechanisms for the development of all organisms.
~) hexactinellids Rhabdocalyp!us ~olIn add ition it seems feasible to capture some vital features of the marine lis (after Schulze 1887); F. cmdanans:
.
' .
.
(k) hydrozoan Halecium halecinum (afenvironment WIth mathematical models.
t H' k 868) (I) lcifi d h d
.
. . .
.
.
.
.
er mc s 1 , ca CI e y rozoan
Using the III silico option for studying growth of manne sessile organMillepora alcicornis (afterAgassiz 1880),
isms is important because, while marine ecosystems are valuable sources of (m) octocoral Rhipidigordia flabellum
known and undiscovered resources, they are also increasingly degraded and
(after Agassiz 1880), (n) scleractinian
endangered. We have only begun to appreciate the aesthetic and ecologi(~tony coral) Porites furcata (afterAgascal value of these systems. New chemical and biological products, some of SIZ 1880)
significant medical or commercial value, are being isolated from marine organisms daily. Some sessile marine organisms produce long-term records of
their interactions with their environment, recorded in their accreting layers of growth. Very-long lived organisms with stable skeletons, such as stony
corals and coralline algae, can provide bioarchives of conditions over the
preceding hundreds or thousands of years. Most importantly, simulation
models can help us better understand the beautiful and intricate ecology of
marine ecosystems by allowing us to focus on the most promising hypotheses in much less time than growth experiments would require and without
disturbing the living system.
The best example of simplicity of a sessile growth form is probably from
the stromatolites. Stromatolites are relatively well studied, since these structures belong to the oldest known fossils. A stromatolite (see Pig.r .aa) grows
by the deposition of material on top of the previous growth stages, which
remain unchanged. This growth process closely resembles a physical deposition process. Some authors (Grotzinger and Rothman 1996) even argue
that it is not possible to distinguish whether the form emerged from a biotic
or an abiotic growth process. Stromatolites represent a transition between
these two. In a number of other cases, such as the Tungussiform, Bacaliform,
and Gymnosoleniform stromatolites shown in Fig.1.3, branching forms develop which at least superficially resemble other marine sessile organisms.
Although branching patterns may emerge in layered physical deposition pro -
cesses, for example in the growth of ammonium chloride crystals (Brener et
al. 1992), there are clearly biological processes at work in the growth of
umbrella-shaped stromatolites which orient themselves toward sunlight.
A similar transition case between abiotic and biotic growth is found in
the growth patterns of many other bacterial colonies (Matsuyama and Matsushita 1993, Ben-Jacob 1993 and 1997). For example, a colony of Paenibacillus
dendritiformis can closely resemble growth patterns found in electro deposition, electric discharge patterns, air bubbles pressed between glass plates
5
must be some way to characterize and compare these forms quantitatively.... Fig. a.ja-n. A phylogenetic overview of
Comparing the shapes of organisms without looking at the finer biological
seaweeds, . sp onge~, and corals: A.. didetails might seem a rather academical exercise however in palaeontology in agrammatic drawings of stromatolites:
c
.. d
. . . '. . .
(a) Baicaliform (b) Gymnosoleniform
many cases only a fossilize macroscopic rorrn is available without any finer () T
·C ' (ft H ff
6)'
c ungussllorm a er 0 man, i97 ;
structures for further study.
B. red seaweeds (Rhodophyta), coralline
In this book we want to show that in addition to field (in vivo) and laboalgae: (d) and (e) (growth forms of
ratory (in vitro) approaches, there is another option for the study of growth
Lithothamnion calcareum), red seaand form in marine sessile organisms. That is by using simulation modw~eds (Rhodophyta): if) Chondrus
els (the "in silica" option). Development of practical simulation models of CrlSpUS; C. ?rown ~eaweeds (Phaeo.
.
.
.
phyta): (g) Dictyota dichotoma: D. green
the growth and development of manne sessile organisms is now both posseaweeds (Chlorophyta): (h) C~dium tosible and important. It is possible because their growth process is relatively mentosum (all seaweeds after Newton
simple and with the enormous progress that has been made toward under- 1931); E. sponges: (i) demosponge Halstanding the basic developmental mechanisms of model organisms, we might
iclona oculata (after Bowerbank 1876),
expect to find some basic mechanisms for the development of all organisms.
~) hexactinellids Rhabdocalyp!us ~olIn add ition it seems feasible to capture some vital features of the marine lis (after Schulze 1887); F. cmdanans:
.
' .
.
(k) hydrozoan Halecium halecinum (afenvironment WIth mathematical models.
t H' k 868) (I) lcifi d h d
.
. . .
.
.
.
.
er mc s 1 , ca CI e y rozoan
Using the III silico option for studying growth of manne sessile organMillepora alcicornis (afterAgassiz 1880),
isms is important because, while marine ecosystems are valuable sources of (m) octocoral Rhipidigordia flabellum
known and undiscovered resources, they are also increasingly degraded and
(after Agassiz 1880), (n) scleractinian
endangered. We have only begun to appreciate the aesthetic and ecologi(~tony coral) Porites furcata (afterAgascal value of these systems. New chemical and biological products, some of SIZ 1880)
significant medical or commercial value, are being isolated from marine organisms daily. Some sessile marine organisms produce long-term records of
their interactions with their environment, recorded in their accreting layers of growth. Very-long lived organisms with stable skeletons, such as stony
corals and coralline algae, can provide bioarchives of conditions over the
preceding hundreds or thousands of years. Most importantly, simulation
models can help us better understand the beautiful and intricate ecology of
marine ecosystems by allowing us to focus on the most promising hypotheses in much less time than growth experiments would require and without
disturbing the living system.
The best example of simplicity of a sessile growth form is probably from
the stromatolites. Stromatolites are relatively well studied, since these structures belong to the oldest known fossils. A stromatolite (see Pig.r .aa) grows
by the deposition of material on top of the previous growth stages, which
remain unchanged. This growth process closely resembles a physical deposition process. Some authors (Grotzinger and Rothman 1996) even argue
that it is not possible to distinguish whether the form emerged from a biotic
or an abiotic growth process. Stromatolites represent a transition between
these two. In a number of other cases, such as the Tungussiform, Bacaliform,
and Gymnosoleniform stromatolites shown in Fig.1.3, branching forms develop which at least superficially resemble other marine sessile organisms.
Although branching patterns may emerge in layered physical deposition pro -
cesses, for example in the growth of ammonium chloride crystals (Brener et
al. 1992), there are clearly biological processes at work in the growth of
umbrella-shaped stromatolites which orient themselves toward sunlight.
A similar transition case between abiotic and biotic growth is found in
the growth patterns of many other bacterial colonies (Matsuyama and Matsushita 1993, Ben-Jacob 1993 and 1997). For example, a colony of Paenibacillus
dendritiformis can closely resemble growth patterns found in electro deposition, electric discharge patterns, air bubbles pressed between glass plates