Complexity



C

Chupacabra

Guest
The question that perplexes me - why does evolution progress
from the simple to the complex? The simple bacteria and
other "primitive" forms of live are by no means less
"viable" then more complex forms -- animals and humans. Many
of these "primitive" species remain the same for the
hundreds of millions of years, survive perfectly in their
enviroments and don't need to evolve into the complex forms.
Indeed, complex forms are often more fragile and susceptible
to the environment perturbations than primitive ones. So how
natural selection alone can explain the general vector of
evolution - from simple and primitive to more complex forms?
Or could there exist some another force apart from the
natural selection -- to "push" evolution in the direction of
complexity, developed nervous system, self-awareness etc.???
 
On Thu, 15 Apr 2004 03:57:36 +0000 (UTC), [email protected]
(chupacabra) wrote:

>The question that perplexes me - why does evolution
>progress from the simple to the complex? The simple
>bacteria and other "primitive" forms of live are by no
>means less "viable" then more complex forms -- animals and
>humans. Many of these "primitive" species remain the same
>for the hundreds of millions of years, survive perfectly in
>their enviroments and don't need to evolve into the complex
>forms. Indeed, complex forms are often more fragile and
>susceptible to the environment perturbations than primitive
>ones. So how natural selection alone can explain the
>general vector of evolution - from simple and primitive to
>more complex forms? Or could there exist some another force
>apart from the natural selection -- to "push" evolution in
>the direction of complexity, developed nervous system, self-
>awareness etc.???

The general idea now is that there is no "progression" of
evolution towards more and more complex forms. It is
necessarily true that the original life forms were
relatively simple. It is also true that we are rather
complex. So if you look at evolution from the original form
to us, it does seem like an increase in complexity. However,
most living things are microorganisms and if you look at
evolution from the original to a modern bacterium, you get a
different impression.

Another way to look at it is as a random walk process.
Evolution tends to spread out organisms in all directions.
However, it started with simple things and there is a lower
bound to how simple an organism can be and still be alive.
So there is necessarily an increase in average complexity
with time. Still, most things remain simple.
 
chupacabra <[email protected]> wrote or quoted:

> The question that perplexes me - why does evolution
> progress from the simple to the complex? The simple
> bacteria and other "primitive" forms of live are by no
> means less "viable" then more complex forms -- animals and
> humans. Many of these "primitive" species remain the same
> for the hundreds of millions of years, survive perfectly
> in their enviroments and don't need to evolve into the
> complex forms. [...]

The bacteria are disadvantaged - since they can't easily
cooperate with one another, and build large structures - and
such cooperation seems to pay off.

They have been (literally) overshadowed - and relegated to
the nooks and crannies of the world. These days much of the
work gets done by macroscopic organisms - such as trees.

Once bacteria ruled the world - but now they in the middle
of a period of decline. Their decline seems likely to
continue - as much of the world's chemical processing gets
taken over by machines - who will have stolen the bacteria's
enzymatic secrets from their genomes.
--
__________
|im |yler http://timtyler.org/ [email protected] Remove
lock to reply.
 
"chupacabra" <[email protected]> wrote in message
news:[email protected]...
> The question that perplexes me - why does evolution
> progress from the simple to the complex? The simple
> bacteria and other "primitive" forms of live are by no
> means less "viable" then more complex forms -- animals and
> humans. Many of these "primitive" species remain the same
> for the hundreds of millions of years, survive perfectly
> in their enviroments and don't need to evolve into the
> complex forms. Indeed, complex forms are often more
> fragile and susceptible to the environment perturbations
> than primitive ones. So how natural selection alone can
> explain the general vector of evolution - from simple and
> primitive to more complex forms? Or could there exist some
> another force apart from the natural selection -- to
> "push" evolution in the direction of complexity, developed
> nervous system, self-awareness etc.???
>

When a niche space is thoroughly exploited by a large clade
or group of large clades of simple creatures what else can
happen, but that species with more complex structures will
be favored in order to exploit a new niche space?

The first niche spaces to be exploited in the early history
of life were those that could support simple organisms.
Therefore there were *always* more available niche spaces
for more complex species than less.

There is no *general vector* of evolution that determines
that complexity will be favored. There is simply the drive
to exploit available habitat in order to avoid competition
from existing and diversified forms. Sometimes this will
actually require the organim becomes more simple, as in the
loss of limb structures in the evolution of marine mammals
from terrestrial mammals. It does seem like the more
successfull pathway for the organism, however, is the
development of new functions.

How large do you think the niche space is, or how many niche
spaces do you think there are, for sentient beings on this
planet? Will the next sentient being have to develop some
new structure or function (say telepathy) in order to out
compete us, or find a new niche space?

Frank
 
On Thu, 15 Apr 2004 03:57:36 +0000 (UTC), [email protected] (chupacabra) wrote:

>The question that perplexes me - why does evolution
>progress from the simple to the complex? The simple
>bacteria and other "primitive" forms of live are by no
>means less "viable" then more complex forms -- animals and
>humans. Many of these "primitive" species remain the same
>for the hundreds of millions of years, survive perfectly in
>their enviroments and don't need to evolve into the complex
>forms. Indeed, complex forms are often more fragile and
>susceptible to the environment perturbations than primitive
>ones. So how natural selection alone can explain the
>general vector of evolution - from simple and primitive to
>more complex forms? Or could there exist some another force
>apart from the natural selection -- to "push" evolution in
>the direction of complexity, developed nervous system, self-
>awareness etc.???

The "drive" towards complexity is due to increased,
successful reproduction in new niches. You said it: "Many of
these 'primitive' species remain the same for hundreds of
millions of years, survive perfectly in their environments
and don't need to evolve into the complex forms." The "ones"
that change and reproduce in new environments, do. Yes, when
the environment changes and kills some of the complex forms,
those complex forms that change and can reproduce in the new
environment, do. Change and reproduction "push" evolution.
 
[email protected] (chupacabra) wrote in message news:<[email protected]>...
> The question that perplexes me - why does evolution
> progress from the simple to the complex?

It is a misunderstanding to say that there is such a thing
as progress in evolution. Evolution is a diversification
process so that all existing species are the leaves on a
branching tree of ancestry. There is no objective sense in
which you can say that any given species is more highly
evolved than another. You can say that some species are
older than others (crocodiles compared with finches, for
example), but this may or may not correspond to the relative
complexity of the species (are finches more complex than
crocodiles?).

> The simple bacteria and other "primitive" forms of live
> are by no means less "viable" then more complex forms --
> animals and humans. Many of these "primitive" species
> remain the same for the hundreds of millions of years,
> survive perfectly in their enviroments and don't need to
> evolve into the complex forms. Indeed, complex forms are
> often more fragile and susceptible to the environment
> perturbations than primitive ones.

Each species has to fit into a niche. Bacteria occupy a
certain niche while more complex organisms occupy others.
One is not better than another, although some environmental
niches may be more enduring.

> So how natural selection alone can explain the general
> vector of evolution - from simple and primitive to more
> complex forms? Or could there exist some another force
> apart from the natural selection -- to "push" evolution in
> the direction of complexity, developed nervous system, self-
> awareness etc.???

There is no drive towards greater complexity. Evolution
often produces simpler variants from more complex variants,
and in terms of raw numbers of organisms, there are vastly
more individuals at the simple end (single celled organisms)
than at the complex end, but while there is a lower bound on
how simple things can be, there is no upper bound.
Increasing the diversity of species must therefore increase
the average complexity (because it can grow upwards but not
downwards), but the distribution will still be heavily
skewed towards the simple end.

Another way of thinking about it is that each species has to
fit a niche and there are more niches (i.e., ways of earning
a living) to be exploited as complexity goes up, so up it
goes. End of story.

There is nothing inevitable about self-awareness,
intelligence, language, morality or any of the other human
traits that people tend to value so much. These traits just
allow us to exploit a particular niche that evolution found
for us. We earn a living by having these properties but at
the cost of having an expensive brain which would not
necessarily be worth the trouble for other species. It
consumes a lot of energy and other nutrients, takes a long
time to develop, and so on. In short, it may not be the most
efficient way to get by in all environments.

And if you really look at the relationship between
reproductive success and properties like intelligence in
humans, you'll find that thoughtful types have fewer
children and usually later in life. This is neither good nor
bad as far as I can see, but it suggests that the link
between general intelligence and human evolution is less
clear than many would have us think. It is unsurprising that
the intellectual elite value intelligence and so tend to
assume it is somehow the 'pinnacle' of evolution, but even
if natural selection did favour intelligence (not obvious),
we have no grounds for considering it more special than any
other specific trait of any other species. It is just a
trait that allows us to exploit a niche, just as flippers
allow dolphins to exploit their niche. Dolphins can't think
like us and we can't swim like them. Who's better? Of course
the values of a society always reflect those of its rulers
(i.e., the intellectual elite), so if you try telling anyone
that intelligence has no particular claim to 'specialness',
you're likely to encounter pretty serious resistance, but I
see no alternative.

H.

---
Like-minds don't notice shared mistakes. Talk to
someone else.
 
<< The question that perplexes me - why does evolution
progress from the simple to the complex? The simple bacteria
and other "primitive" forms of live are by no means less
"viable" then more complex forms -- animals and humans. Many
of these "primitive" species remain the same for the
hundreds of millions of years, survive perfectly in their
enviroments and don't need to evolve into the complex forms.
Indeed, complex forms are often more fragile and susceptible
to the environment perturbations than primitive ones. So how
natural selection alone can explain the general vector of
evolution - from simple and primitive to more complex forms?
Or could there exist some another force apart from the
natural selection -- to "push" evolution in the direction of
complexity, developed nervous system, self-awareness etc.???
>>

I suggest two things.

1. life becomes more complex because life IS an energy
moderator (keeping within the temp range that allows for
liquid water, highest enzyme reactions, etc.) Thus energy
moderation with modification through descent.

And complexity is the way to better modify that energy
moderating system - better adapt life to its environment.

2. As to speeds of change - I suggest this model

As environmental fitness increases, stabilizing selection
increases, and directional and diversifying selection
decreases, and vice versa.

Thus when adapted well - little change is forced. When not
adapted, big change is selected for.
 
I found myself trying to tease out what exactly you mean by
complexity, which I've found is where most conversations of
this sort go awry. "More complex =~ larger" is loosely
implied here, as is "more complex =~ more differentiable
cell types" and as also is "more complex =~ more
interactions". Rather than wager more likely misguided
guesses, I figured I'd ask you if you could espouse a bit on
your question. (This of course is the penultimate problem,
well at least IMO. Complexity is about an umbrella a term as
I can think of, and each of these implied meanings I've
guessed at above has an entire school of evolutionary
thinking).

"chupacabra" <[email protected]> wrote in message
news:[email protected]...
> The question that perplexes me - why does evolution
> progress from the simple to the complex? The simple
> bacteria and other "primitive" forms of live are by no
> means less "viable" then more complex forms -- animals and
> humans. Many of these "primitive" species remain the same
> for the hundreds of millions of years, survive perfectly
> in their enviroments and don't need to evolve into the
> complex forms. Indeed, complex forms are often more
> fragile and susceptible to the environment perturbations
> than primitive ones. So how natural selection alone can
> explain the general vector of evolution - from simple and
> primitive to more complex forms? Or could there exist some
> another force apart from the natural selection -- to
> "push" evolution in the direction of complexity, developed
> nervous system, self-awareness etc.???
 
On Thu, 15 Apr 2004 03:57:36 +0000 (UTC), [email protected]
(chupacabra) wrote:

The question that perplexes me - why does evolution progress
from the simple to the complex? The simple bacteria and
other "primitive" forms of live are by no means less
"viable" then more complex forms -- animals and humans. Many
of these "primitive" species remain the same for the
hundreds of millions of years, survive perfectly in their
enviroments and don't need to evolve into the complex forms.
Indeed, complex forms are often more fragile and susceptible
to the environment perturbations than primitive ones. So how
natural selection alone can explain the general vector of
evolution - from simple and primitive to more complex forms?
Or could there exist some another force apart from the
natural selection -- to "push" evolution in the direction of
complexity, developed nervous system, self-awareness etc.???

RN: The general idea now is that there is no "progression"
of evolution towards more and more complex forms. It is
necessarily true that the original life forms were
relatively simple. It is also true that we are rather
complex. So if you look at evolution from the original form
to us, it does seem like an increase in complexity.

However, most living things are microorganisms and if you
look at evolution from the original to a modern bacterium,
you get a different impression.

Another way to look at it is as a random walk process.
Evolution tends to spread out organisms in all directions.
However, it started with simple things and there is a lower
bound to how simple an organism can be and still be alive.
So there is necessarily an increase in average complexity
with time. Still, most things remain simple.

MR:I think the "general idea" there has been no progression
towards more complex forms is misleading. Looking at the
Archeon, Proterozoic, Paleozoic, Mesozoic and Cenozoic
eras there is certainly evidence of more diversity..even
with the mass extinctions which have occurred. And I
think in some important ways there have been a
progression from more simple forms to complex forms. I
realize bacteria have always been the Kings of the earth
but it seems rather narrow to exclude all other life and
just compare modern bacteria to ancient bacteria in terms
of complexity.

The first cells formed in the Archeon eon and were
prokaryotic. Given the absence of free oxygen they must have
secured energy through anaerobic pathways. Then during the
Proterozoic eon oxygen began to accumulate. This ultimately
stopped the further chemical origin of living cells. Aerobic
respiration became the dominant energy releasing pathway.
This led to the rise of multicelled eukaryotes and their
invasion of far flung environments.

It seems to me going from anaerobic pathways to aerobic
respiration and from cells without a nucleus to multicelled
eukaryotes represented a progression in complexity.

Michael Ragland
 
"r norman" <rsn_@_comcast.net> wrote in message
>
> Another way to look at it is as a random walk process.
> Evolution tends to spread out organisms in all directions.
> However, it started with simple things and there is a
> lower bound to how simple an organism can be and still be
> alive. So there is necessarily an increase in average
> complexity with time. Still, most things remain simple.
>
This was Sephen Gould's argument. The problem is that a
"random walk" could only produce something that looked
random - big agglomerations of cells maybe, but to
exquisitely structured into a co-operative organism. It
is true that some simple solutions to the problems of
living still work. However for a substantial subset of
organisms the more complex form offers an advantage. For
instance, jawed mouths are more complex than jawless
mouths and look longer to evolve. However the jawed
fishes have radiated to fill a huge variety of niches,
and even spread to the land, whilst the jawless solution
is only viable in a few specialised niches, such as the
parasitic hagfish and lampreys.
 
r norman <rsn_@_comcast.net> wrote or quoted:

> The general idea now is that there is no "progression" of
> evolution towards more and more complex forms. [...]

Not /even/ Gould believed that! ;-)

> It is necessarily true that the original life forms were
> relatively simple. It is also true that we are rather
> complex. So if you look at evolution from the original
> form to us, it does seem like an increase in complexity.
> However, most living things are microorganisms and if you
> look at evolution from the original to a modern bacterium,
> you get a different impression.
>
> Another way to look at it is as a random walk process.
> Evolution tends to spread out organisms in all directions.
> However, it started with simple things and there is a
> lower bound to how simple an organism can be and still be
> alive. So there is necessarily an increase in average
> complexity with time. Still, most things remain simple.

That is what Gould argued in his book on the subject.

...but I don't think he convinced very many people.

I - for example - think his idea is complete nonsense.

IMO, Dawkins destroys Gould's argument thus:

``Notwithstanding Gould?s just scepticism over the tendency
to label each era by its newest arrivals, there really is a
good possibility that major innovations in embryological
technique open up new vistas of evolutionary possibility and
that these constitute genuinely progressive improvements
(Dawkins 1989; Maynard Smith & Szathm?ry 1995). The origin
of the chromosome, of the bounded cell, of organized

multicellularity, of gastrulation, of molluscan torsion,
of segmentation ? each of these may have constituted a
watershed event in the history of life. Not just in the
normal Darwinian sense of assisting individuals to survive
and reproduce, but watershed in the sense of boosting
evolution itself in ways that seem entitled to the label
progressive. It may well be that after, say, the invention
of multicellularity, or the invention of metamerism,
evolution was never the same again. In this sense there
may be a one-way ratchet of progressive innovation in
evolution.''

...and concludes:

``For this reason over the long term, and because of the
cumulative character of coevolutionary arms races over the
shorter term, Gould?s attempt to reduce all progress to a
trivial, baseball-style artefact constitutes a surprising
impoverishment, an uncharacteristic slight, an unwonted
demeaning of the richness of evolutionary processes.''

- http://www.world-of-
dawkins.com/Dawkins/Work/Reviews/1997-06fullhouse.shtml

I think Gould's point here is toast.

...and this is before we have made much mention of the
specific effects of arms races between large-brained
organisms trying to outwit each other.

Gould isn't here to defend himself...

...though I know he would argue that looking at large-
brained organisms would be anthropomorphic...

...so does anyone else care to argue that evoultion has no
large-scale direction, or trend favouring the accumulation
of technology, (and thus complexity)?

On the face of it, it is hard to look at the world at
the moment and not have it scream "PROGRESS" at you on
all channels.

Gould only managed it at all because he was a paleontologist
- and not a technologist - but even then his proofreader
should have told him he was talking complete nonsense.
--
__________
|im |yler http://timtyler.org/ [email protected] Remove
lock to reply.
 
Frank Reichenbacher <[email protected]> wrote or quoted:

> There is no *general vector* of evolution that determines
> that complexity will be favored.

Two effects seem to fit this bill - at least on a
large scale:

* The progressive accumulation of technology - e.g.
photosynthesis, haemoglobin, etc;

* Co-evolutionary arms races between large-brained
organisms;

The first one it the fundamental one. The second one does
directly produce complexity - but it really relies on the
first one to explain why it is ultimately favoured.

The fact that nature is constantly learning new tricks -
but rarely forgets old ones that were any use gives
evolution an unmistakable progressive character - a
direction, if you will.

Some would go even further - and say that evolution has a
"goal" - or at least is behaving as though it has one - by
consitently heading in a specific direction.
--
__________
|im |yler http://timtyler.org/ [email protected] Remove
lock to reply.
 
<< Another way to look at it is as a random walk process.
Evolution tends to spread out organisms in all directions.
However, it started with simple things and there is a lower
bound to how simple an organism can be and still be alive.
So there is necessarily an increase in average complexity
with time. Still, most things remain simple.
>>

If I am correct this is the Gould idea that he suggests as
seen by a drunk leaving a bar. But this 'falls down' when
you look at the option Gould never mentions. The drunk lays
down and does not move at all . And this from a co-creator
of punctuated equilibrium! Tom Hendricks, Musea zine ed.
http://musea.digitalchainsaw.com"

Musea GUARANTEES every musician, painter, writer, etc. a
REVIEW - a tough review - a fair review.

Contact me for our policy. Samples:
http://musea.digitalchainsaw.com/reviews1.html
 
in article [email protected], chupacabra at
[email protected] wrote on 4/14/04 8:57 PM:

> The question that perplexes me - why does evolution
> progress from the simple to the complex? The simple
> bacteria and other "primitive" forms of live are by no
> means less "viable" then more complex forms -- animals and
> humans. Many of these "primitive" species remain the same
> for the hundreds of millions of years, survive perfectly
> in their enviroments and don't need to evolve into the
> complex forms. Indeed, complex forms are often more
> fragile and susceptible to the environment perturbations
> than primitive ones. So how natural selection alone can
> explain the general vector of evolution - from simple and
> primitive to more complex forms? Or could there exist some
> another force apart from the natural selection -- to
> "push" evolution in the direction of complexity, developed
> nervous system, self-awareness etc.???

I already see a large number of responses and my personal
response has pretty well been represented if you stitch
together bits from the set of other responses; but I just
can't resist putting in my 2 cents on a subject that
interests me so much.

Evolution has produced increasingly complex organisms
BECAUSE IT CAN. I do not mean this to be sarcastic or devoid
of meaning. As I see it, life originated because there was a
sufficiently potent energy gradient across space that life
could effectively dissipate. The energy rich side of the
gradient fuels living processes and the cold of the upper
atmosphere, especially on the dark side of the planet, draws
out the energy after its quality has been degraded to yield
the work of constructing and maintaining the living systems.
The constructive emergence of dissipative systems like this
involves an increase in complexity, by definition, and it
seems to be generically true that such systems continue to
increase in complexity unless they run into constraints. The
two sources of constraint that jump into my mind are the
degree of potential represented by the gradient (it takes a
more potent gradient to support development of a more
complex system) and the material limitations of the system.
Life is clearly far less constrained in the latter way
compared to say the diversity of dissipative structures able
to form in the earth's atmosphere. As pointed out by others,
you can easily imagine some of the ecological factors that
provide mechanisms of increasing species complexity. For
example, the origin of simple organisms creates niches
(potentials) that can be best filled by the emergence of
more complex organisms, which creates new niches, and so on.
It also takes more fuel (and a greater cold sink) to support
the evolution of more species rich and complex food webs
than to support smaller food webs. I would predict that the
most complex organisms would be particularly vulnerable to
extinction if the sun suddenly became dimmer.

Guy
 
"chupacabra" <[email protected]> wrote in message
news:[email protected]...
> The question that perplexes me - why does evolution
> progress from the simple to the complex?

Perhaps for you personally, it might be a philosophically
pioneering move to start perceiving this your perplexity as
a part of a perfectly profound and, according to fundamental
laws of fundamental physics and neuropsychobiology, fully
legitimate, philosophical feeling! Whether or not you are
now being told about this feeling for the 'premiere fois',
it is necessary to recognize it in order to achieve an
exceptionally pleasing take on, or philosophically omni-
inventorial overview (including of "first causes") of what
is going on.

As part of preparing oneself to be *entirely*
philosophically and intellectually realistic, one has to
consistently incorporate a dimension of absolute mystery
into such a philosophical overview. But that is not all!
What has to be deliberately intellectually incorporated is a
"Tolerance Principled" acceptance of (and 'analytical
approach affecting' attitude towards) an
ultimate/fundamental uncertainty (about what is going on)
RIGHT ALONGSIDE the _complete certainty_ that we exist
['have a probability score very close to 1' :)] as part of
the self-patterning - into variously complex classes of self-
knots (as suggested by the quantum-'mechanical' String/M-
theory) - of What Is.

And, don't trust people (whose reply posts pre-date mine;)
to have an as realistically reasoned and tightly science-
aligned philosophical spine as mine! ;-|

This because they have not found - or have even refused
to follow ;-< - my philosophical way around the fact that
we tend to be, and _have evolved_ to tend to be,
"AEVASIVE". %-}

------------------------------------------------------------
------------
AEVASIVE _is_ complex yet simple set of science-aligned
philosophical insights _thus compactly conceptualized_.

What I mean by AEVASIVE I mean with a pragmatic implicitness
and a "fuzzsilly" logic no more _imprecise and silly_ than
is for strategic reasons 'accEPTable'.

[This strategy is part of a "light-making" (both
illuminating and relief-achieving) anthropocentric approach
at grasping What Is going - and approach that centrally
includes a explanatory terminological theme that suits being
described as "SEPTIC humored"]

By EPT I insinuate (refer to) an in a sense effectively
philosophy terminating explanatory platform terminology
that I contrived as part of an only semi-confused campaign
of self-edutainment (now extended into an Internet-based
philanthropically oriented organization for the promotion
of EPT and EPT-aligned ideas - namely EAIMC Internetional
Ptd Lty. %-)]
------------------------------------------------------------
----------------
-

Most generally, Evolution is (even if it might - for all I
care - be interspersed by local slippages into _devolution_)
best and preeminently definable NOT JUST as a "filling up of
niches" - which in turn may be seen as
projections/realizations of potentials of a (quasi-Platonic)
biological configuration space - but as a patterning process
that on the whole for a while produces: "increasingly
complex patterns on decreasing numbers of occassions in
decreasing numbers of places".

P
 
in article [email protected], chupacabra at
[email protected] wrote on 15/4/04 3:57 PM:

> The question that perplexes me - why does evolution
> progress from the simple to the complex? The simple
> bacteria and other "primitive" forms of live are by no
> means less "viable" then more complex forms -- animals and
> humans. Many of these "primitive" species remain the same
> for the hundreds of millions of years, survive perfectly
> in their enviroments and don't need to evolve into the
> complex forms. Indeed, complex forms are often more
> fragile and susceptible to the environment perturbations
> than primitive ones. So how natural selection alone can
> explain the general vector of evolution - from simple and
> primitive to more complex forms? Or could there exist some
> another force apart from the natural selection -- to
> "push" evolution in the direction of complexity, developed
> nervous system, self-awareness etc.??

My theory is explained here

ed-evolution.co.nz/selfishH/selfish_helper.ssi

I have since I wrote this paper added some more aspects
but they have not been published either in journals or to
the web as et

--

Phillip Smith phills@(buggger).co.nz replace bugger with
ihug http://www.applied-evolution.co.nz

"he who is smeared with blubber has the kindest heart" -- a
Greenland Eskimo adage
 
IRR <[email protected]> wrote or quoted:

> I found myself trying to tease out what exactly you mean
> by complexity, which I've found is where most
> conversations of this sort go awry. "More complex =~
> larger" is loosely implied here, as is "more complex =~
> more differentiable cell types" and as also is "more
> complex =~ more interactions". Rather than wager more
> likely misguided guesses, I figured I'd ask you if you
> could espouse a bit on your question. (This of course is
> the penultimate problem, well at least IMO. Complexity is
> about an umbrella a term as I can think of, and each of
> these implied meanings I've guessed at above has an entire
> school of evolutionary thinking).

There are several ways of defining biological complexity.

Common metrics involve things like counting the number of
different cell types an organism produces - and estimating
the "kolmogorov complexity" of its genome.

Though the definitions may differ in detail, they tend to be
correlated - and in discussions like this it tends not to
matter very much which one you use.
--
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TomHendricks474 wrote:
> << Another way to look at it is as a random walk process.
> Evolution tends to spread out organisms in all directions.
> However, it started with simple things and there is a
> lower bound to how simple an organism can be and still be
> alive. So there is necessarily an increase in average
> complexity with time. Still, most things remain simple.
> >>
>
>
> If I am correct this is the Gould idea that he suggests as
> seen by a drunk leaving a bar. But this 'falls down' when
> you look at the option Gould never mentions. The drunk
> lays down and does not move at all .

And then he dies. It's called no evolution, and leads to
extinction.

Goulds' point is simply that if you start of simple, then
the only direction to go is towards complexity. If you're at
the bottom, the only way to go is up...

Bob

--
Bob O'Hara

Dept. of Mathematics and Statistics
P.O. Box 4 (Yliopistonkatu 5) FIN-00014 University of
Helsinki Finland Telephone: +358-9-191 23743 Mobile:
+358 50 599 0540 Fax: +358-9-191 22 779 WWW:
http://www.RNI.Helsinki.FI/~boh/ Journal of Negative
Results - EEB: http://www.jnr-eeb.org
 
On Thu, 15 Apr 2004 23:44:55 +0000 (UTC), "Malcolm"
<[email protected]> wrote:

>
>"r norman" <rsn_@_comcast.net> wrote in message
>>
>> Another way to look at it is as a random walk process.
>> Evolution tends to spread out organisms in all
>> directions. However, it started with simple things and
>> there is a lower bound to how simple an organism can be
>> and still be alive. So there is necessarily an increase
>> in average complexity with time. Still, most things
>> remain simple.
>>
>This was Sephen Gould's argument. The problem is that a
>"random walk" could only produce something that looked
>random - big agglomerations of cells maybe, but to
>exquisitely structured into a co-operative organism. It is
>true that some simple solutions to the problems of living
>still work. However for a substantial subset of organisms
>the more complex form offers an advantage. For instance,
>jawed mouths are more complex than jawless mouths and look
>longer to evolve. However the jawed fishes have radiated to
>fill a huge variety of niches, and even spread to the land,
>whilst the jawless solution is only viable in a few
>specialised niches, such as the parasitic hagfish and
>lampreys.
>
>
A number of people have commented on my statement about
evolution as a random walk with no specific tendency to
evolve towards more complexity. Here is a better description
of what I was trying to explain.

Imagine an abstract "phenotype landscape" spread out, each
point representing one possible type of organism. Imagine it
organized by "complexity", something we can't really define
or measure but we know it when we see it. On one side are
the simple things, on the far end are the most complex.
There is a wall on the simple end -- too simple and you
can't sustain life. We don't know (or haven't reached) a
wall on the complex end. In the beginning, you start with a
bunch of cells all bunched along the wall at the simple end.
Evolution is a random walk. There is no specific tendency to
get more complex nor is there any specific tendency to get
less complex. There is only a tendency to change, to move
from where you are to another location. The changes are
random in direction; a "drunkard's walk". Over time,
organisms tend to fill the landscape, spreading out over
everything. As time goes on, organisms spread farther and
farther into the complex region. The leading edge always
gets more and more complex. The average always gets more and
more complex.

Still, the mechanism of evolution in no way demonstrates a
tendency to produce complexity. The mechanism of evolution
is to produce and select for change. The "move towards
complexity" is simply a product of the diffusion process
(the random walk) and the boundary conditions (a barrier at
the simple end) and the initial condition (start
concentrated at the simple end).

The existence today of a huge variety of less complex
organisms (most genomic variability lies in the prokaryotes)
shows that there are enormous numbers of habitats and niches
where simple shows a high degree of fitness. On the other
hand, there are enormous numbers of niches where complex
shows higher fitness. We rather large terrestrial organisms
tend to focus on the latter, completely overlooking the
former. If we were microscopic aquatic organisms, we might
have a different perspective.
 
Malcolm <[email protected]> wrote or quoted:
> "r norman" <rsn_@_comcast.net> wrote in message

> > Another way to look at it is as a random walk process.
> > Evolution tends to spread out organisms in all
> > directions. However, it started with simple things and
> > there is a lower bound to how simple an organism can be
> > and still be alive. So there is necessarily an increase
> > in average complexity with time. Still, most things
> > remain simple.
>
> This was Sephen Gould's argument. The problem is that a
> "random walk" could only produce something that looked
> random - big agglomerations of cells maybe, but to
> exquisitely structured into a co-operative organism.

Gould's argument was that *complexity* followed a
random walk.

This criticism doesn't apply to that claim.

It /would/ apply to the claim that evolution - or genomes -
followed a random walk - but Gould never made those
assertions in the first place.
--
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