Morphological Parameters in Evolution

[Thunderbird]

This is a continuation From Re: Natural Selection vs evolution

 

 

Originally Posted by Thunderbird

If you agree with the first part of my post {and I’m not sure if you do} which addresses physical forms being inherently inevitable, than why not intelligent reptiles? What would make this morphological niche any different than wings that evolved in separate species.

 

Reason

I don't reject the notion of intelligent reptiles per se, I rejected the notion that if there hadn't been a devastating collision 65 million years ago, we would be blogging along side our humanoid reptilian dinosaur counterparts.

 

 

Thunderbird

 

I didn’t mean along side of us, but instead of us. Let me be specific on this, we as a species are not in any way inevitable.

 

What I do see from studying the fossil record and the geometry of body plans is that certain morphological traits will be optimum in exploiting the terrestrial environments while others will be left behind as time progress.

535 million years ago there existed many more basic phyla level planes than today. The environment and more importantly the static physical laws acted as a precise filter and sculptor to shape the optimum forms to, walk, run, swim, fly, etc.

 

Thunderbird

 

These sorts of adaptations are clearly advantages. Flight over fleet, brain over brawn.

The cycle of Genetic sampling driven by adaptation would eventually form into a basin of attraction around lager brains and reasoning. It seems reasonable that once this became a exploitable niche it would develop expediently in a very short time just as every other evolutionary advance. Our own sudden dominants over our bigger, faster and much more teether brethren is solid proof of this.

 

 

 

Reason

Maybe I don't completely agree with your initial assertion. Although I'm not an expert, I am open to ideas. While I understand the influence of morphology, I'm not convinced of the concept of inevitability when it comes to the evolutionary process. Inevitability seems clear when tracing backwards, but it is difficult, if not impossible, to predict an evolutionary outcome for any particular species. For example, if there were were no animal species on this planet with the capability of flight, why would we assume that it is inevitable that some species will develop that capability as it evolves? What are some examples of inevitable traits in plants and animals that we have yet to observe?

 

Thunderbird

 

I don’t have a crystal ball but consider that vertebrates have only been here for aprox 500 million years and the planet has at least another couple billion years to live. The penguins my evolve to the proportional forms of whales. Some sea going reptiles 100 million yrs ago Looked uncannily like dolphins. Dinos grew hair. Consider the photosynthetic process. Chlorophyll is not ever been replaced by any other process even given billions of years of trail and error, why? Maybe it is as chemical inevitability just as the periodic table of elements. I see morphology the same way as coded within the DNA as probabilities just waiting to meet with inevitability inherent in the same system.

Thirty years ago scientist described life as some kind cosmic accident, I don’t see this, life to me is an obvious part of the system and has its place even if were not evolved enough to see it. Conciseness also seems to me as an inevitable out come just as the periodic table of element, and seems to be a continual process of quantum refinement of energy.

 

Thunderbird

 

Although these reptiles would first need to follow a similar morphological path as an arboreal dwelling- bipedal-grasping-hunting and in social-migrating, tool making etc. The brain would form around these inherent terrestrial basins of attractions, as would the optimum body plan for this particular linear niche.

Reason

Your first sentence here reflects exactly what I'm saying. Why would you assume that it is inevitable that reptiles, or any other particular species, are likely to follow a similar morphological path as humans? The data doesn't support this as brain development in reptiles has remained relatively static for millions of years, even with diversification. From the standpoint of natural selection, advanced brain functioning in reptiles hasn't proven to be necessary.

 

Thunderbird

 

Necessity is the mother of invention we may find ourselves extinct leaving open a evolutionary niche for the next intelligent species. Remember given enough time evolution tends to fill any available vacuum, if higher conciseness is advantages the vacuum should be filled given enuogh time

.

 

Thunderbird

 

I’ll go one step further and farther and use these extrapolations and pose that if we were to some day meet with civilizations from other worlds we would all have almost identically formed hands.

 

Reason

This is pure speculation, and a bit egocentric don't you think? Besides, my understanding is that current theory holds that bipedalism had a greater bearing on human evolution than our opposable thumbs

.

 

 

 

Thunderbird

 

The reason I chose the hand as a universal feature of intelligents is because the brain formed in conjunction with it.

Austolopithacus walked upright and contained a small brain. The geometry of the hand is the optimum tool for manipulating

the terrestrial environment as a builder and tool maker.

[Buffy]

No morphological trait is "inherently superior": traits have advantage within the context of a specific environment.

 

Traits also may or may not go away if they are no longer and advantage, and they only really get forced out if they become a disadvantage, usually due to a change in the environment!

 

Do you want to clarify what point you're trying to make here?

 

Any event, once it has occurred, can be made to appear inevitable by a competent historian, :doh:

Buffy

[Thunderbird]

No morphological trait is "inherently superior": traits have advantage within the context of a specific environment.

 

Traits also may or may not go away if they are no longer and advantage, and they only really get forced out if they become a disadvantage, usually due to a change in the environment!

 

Do you want to clarify what point you're trying to make here?

 

Any event, once it has occurred, can be made to appear inevitable by a competent historian,

Buffy

 

Hi Buffy, I apologize for asking a question to yours, but this is the best way I know to get on the same page here.

Do you believe the periodic table is inevitable out come the physical laws that govern star formation? How about planets, water, the mineral kingdom, the cell, the DNA molecule

Do you believe life is an inevitability given the right conditions?

 

Where is the point of where form and function and physical laws part ways?

 

In 1981, a highly speculative and controversial account of morphogenesis was offered by Rupert Sheldrake which has been at times associated with Jung's concepts of the collective unconscious and of the archetype. 69) Sheldrake's hypothesis of formative causation postulates the existence of morphogenetic fields as presently unrecognized causal agents responsible for producing all of the forms, or patterns of structural organization, of matter and of living organisms. These fields are held to be actual physical fields, although they are non-energetic and non-local - they are distributed without diminishment throughout space and time. Sheldrake proposed that the forms of molecules, crystals, cells, complex organs such as eyes, etc., the overall structures of all living creatures, and even the structure of entire societies are all established by a process of morphic resonance by which a seed structure is guided to its final form by resonating with a particular pre-existing morphogenetic field. Each aspect of form is associated with a unique morphogenetic field; thus Sheldrake's hypothesis involves unfathomably many of these fields which may grow or diminish in strength in relation to the degree of morphic resonance within the particular field. New structures may appear through the action of a morphogenetic field, giving it an inherently creative aspect as well. The morphogenetic fields, then, act as a collective memory by which previously established patterns guide the emergence of new forms and by which novel occurrences of form proliferate

[Buffy]

Hi Buffy, I apologize for asking a question to yours, but this is the best way I know to get on the same page here.

No problem! Its the best way to define problems, find solutions and learn!

Do you believe the periodic table is inevitable out come the physical laws that govern star formation?

First, they definitely are not an "outcome of the physical laws that govern star formation." I really don't see how that has anything to do with it, so I'll have to ask you back, why do you see a link?

 

Now the Periodic Table has the structure it does because of the fundamental physical constants of nature: The relative strengths of the electroweak and gravitational forces, the properties of quarks and leptons, etc. If any of the intrinsic values of these elements were different, the Periodic Table could be quite different.

 

Now the basic elements of the standard model are--relatively speaking--fairly simple, and their properties and the structure of their direct consequences--like the structure of the Periodic Table--are based on mathematics which dictates the pattern in a fairly straight-forward way.

 

But when you start talking about much more complex objects:

How about planets, water, the mineral kingdom, the cell, the DNA molecule

...you get into a situation where the highly complex interactions of individually complex structures with a lot of potential variability thrown in and random effects causing wide divergences in various terms, then there is less and less of an "intrinsically right" solution.

 

Like all complex mathematical functions, there will be patterns that repeat: see the thread 13916 for an interesting discussion concerning the fact that the Fibonacci number sequence readily manifests itself in spiral shapes of all kinds throughout nature from sunflowers to galaxies. But this is just *math*. Is it intrinsic, well, sort of, its the way that math works: it has patterns, but this is hardly magical.

 

There is a mathematical principle that is important: simplicity is much easier to maintain than complexity. Why do we have two eyes, hands, feet, etc. Well, to a certain extent, its luck, but its also harder to create and maintain a structure that has 3, 4, 5, etc, identical elements.

 

Why are eyes spherical? because when you blow up any membrane, its spherical, unless it sits in a structure that puts external pressure on it. Its harder--although not impossible--to generate a membrane that maintains an hourglass shape.

 

Are these patterns and shapes "intrinsic?" Well, sort of, but does that "intrinsicity" have meaning? Not really: its just math!

 

Do you believe life is an inevitability given the right conditions?

"Inevitable" in what sense? I'd argue that its not: it may be "highly likely" but that doesn't mean that you couldn't have a Universe with all the same properties as ours that never evolved any life!

 

Where is the point of where form and function and physical laws part ways?

All physical laws have form, and while I'd argue they have no "purpose"--that starts to imply "intent" of a "creator" which is unnecessary to justify the way things are--they "function" in many ways, and those functions have implications for the exact properties that are observed in the Universe.

 

So, given that, am I getting any closer to the concepts you're trying to convey here?

 

I must admit I'm still quite unclear on what you are trying to demonstrate....

 

The very purpose of existence is to reconcile the glowing opinion we have of ourselves with the appalling things that other people think about us,

Buffy

[Thunderbird]

No problem! Its the best way to define problems, find solutions and learn!

 

First, they definitely are not an "outcome of the physical laws that govern star formation." I really don't see how that has anything to do with it, so I'll have to ask you back, why do you see a link?

 

Stars create elements.

 

 

 

 

 

Like all complex mathematical functions, there will be patterns that repeat: see the thread 13916 for an interesting discussion concerning the fact that the Fibonacci number sequence readily manifests itself in spiral shapes of all kinds throughout nature from sunflowers to galaxies. But this is just *math*. Is it intrinsic, well, sort of, its the way that math works: it has patterns, but this is hardly magical.

 

I'm the one who introduced the math of the Fibonacci to that thread to

address the fact that it is an intrinsic and a universal organizing principle. This is my point, to look at Morphology in ways that address laws of physical constraints. but I never said "magical" someone else used that Word.

 

 

 

 

Are these patterns and shapes "intrinsic?" Well, sort of, but does that "intrinsicity" have meaning? Not really: its just math!

 

It is math but, never just.

 

"Inevitable" in what sense? I'd argue that its not: it may be "highly likely" but that doesn't mean that you couldn't have a Universe with all the same properties as ours that never evolved any life!

Life is a property of the universe.:)

 

All physical laws have form, and while I'd argue they have no "purpose"--that starts to imply "intent" of a "creator" which is unnecessary to justify the way things are--they "function" in many ways, and those functions have implications for the exact properties that are observed in the Universe.

"Purpose" "intent" "creator" is in quote's why? I have not used these words, and certainly not implying creationism. This is a dissusion on science.

[Thunderbird]

 

So, given that, am I getting any closer to the concepts you're trying to convey here?

 

I must admit I'm still quite unclear on what you are trying to demonstrate....

 

This may help:)

 

Chaos and Complexity

 

One of the themes straddling both biological and physical sciences is the quest for a mathematical model of phenomena of emergence (spontaneous creation of order), and in particular adaptation, and a physical justification of their dynamics (which seems to violate physical laws).

 

The physicist Sadi Carnot, one of the founding fathers of Thermodynamics, realized that the statistical behavior of a complex system can be predicted if its parts were all identical and their interactions weak. At the beginning of the century, another French physicist, Henri Poincare`, realizing that the behavior of a complex system can become unpredictable if it consists of few parts that interact strongly, invented "chaos" theory. A system is said to exhibit the property of chaos if a slight change in the initial conditions results in large-scale differences in the result. Later, Bernard Derrida will show that a system goes through a transition from order to chaos if the strength of the interactions among its parts is gradually increased. But then very "disordered" systems spontaneously "crystallize" into a higher degree of order.

First of all, the subject is "complexity", because a system must be complex enough for any property to "emerge" out of it. Complexity can be formally defined as nonlinearity.

 

The world is mostly nonlinear. The science of nonlinear dynamics was originally christened "chaos theory" because from nonlinear equations unpredictable solutions emerge.

 

A very useful abstraction to describe the evolution of a system in time is that of a "phase space". Our ordinary space has only three dimensions (width, height, depth) but in theory we can think of spaces with any number of dimensions. A useful abstraction is that of a space with six dimensions, three of which are the usual spatial dimentions. The other three are the components of velocity along those spatial dimensions. In ordinary 3-dimensional space, a "point" can only represent the position of a system. In 6-dimensional phase space, a point represents both the position and the motion of the system. The evolution of a system is represented by some sort of shape in phase space.

 

The shapes that chaotic systems produce in phase space are called "strange attractors" because the system will tend towards the kinds of state described by the points in the phase space that lie within them.

 

The program then becomes that of applying the theory of nonlinear dynamic systems to Biology.

 

Inevitably, this implies that the processes that govern human development are the same that act on the simplest organisms (and even some nonliving systems). They are processes of emergent order and complexity, of how structure arises from the interaction of many independent units. The same processes recurr at every level, from morphology to behavior.

 

Darwin's vision of natural selection as a creator of order is probably not sufficient to explain all the spontaneous order exhibited by both living and dead matter. At every level of science (including the brain and life) the spontaneous emergence of order, or self-organization of complex systems, is a common theme.

 

Koestler and Salthe have shown how complexity entails hierarchical organization. Von Bertalanffi's general systems theory, Haken's synergetics, and Prigogine's non-equilibrium Thermodynamics belong to the class of mathematical disciplines that are trying to extend Physics to dynamic systems.

 

These theories have in common the fact that they deal with self-organization (how collections of parts can produce structures) and attempt at providing a unifying view of the universe at different levels of organization (from living organisms to physical systems to societies).

[freeztar]

Hey TB, I see what you are getting at, but it is a false assumption. It's just as likely that the hominid morphology would not develop, but in this case it did. It was advantageous for human ancestors to develop a hominid morphology to adapt to the environment at that time and place. Given a different environment, we may all still be walking around on all fours.

[Thunderbird]

Hey TB, I see what you are getting at, but it is a false assumption. It's just as likely that the hominid morphology would not develop, but in this case it did. It was advantageous for human ancestors to develop a hominid morphology to adapt to the environment at that time and place. Given a different environment, we may all still be walking around on all fours.

 

This is true in our own earth's history, but what I'm proposing is general morphological parameters set by Physics and unencumbered by time. Our own history is just a small sample of what evolution could create given enough time. To assume that there are no archetypal forms is also an assumption, don't you agree? DNA sampling is not a closed system, it is subject to physical laws that are very stable. It would seem logical that this stability factor would create a set range of possible forms.

[freeztar]

This is true in our own earth's history, but what I'm proposing is general morphological parameters set by Physics and unencumbered by time. Our own history is just a small sample of what evolution could create given enough time. To assume that there are no archetypal forms is also an assumption, don't you agree?

 

Yes, I agree. It is an assumption either way.

 

DNA sampling is not a closed system, it is subject to physical laws that are very stable. It would seem logical that this stability factor would create a set range of possible forms.

 

Perhaps, but I don't think there's any way to determine that.

[Buffy]

First, they definitely are not an "outcome of the physical laws that govern star formation." I really don't see how that has anything to do with it, so I'll have to ask you back, why do you see a link?

Stars create elements.

Yeah, but that's like saying because refrigerators create ice, then they *define* the properties of ice. That's definitely putting the cart before the horse.

 

But what is it about it that you find interesting?

I'm the one who introduced the math of the Fibonacci to that thread to address the fact that it is an intrinsic and a universal organizing principle. This is my point, to look at Morphology in ways that address laws of physical constraints. but I never said "magical" someone else used that Word.

Glad its not "magical" that you're looking for then!

 

The point where I'm perceiving that we differ--and I may be wrong because I just don't understand what point you're trying to make--is that Fibonacci is so simple, it shows up all over the place. But that does not mean that two examples--say galaxies and hurricanes--are at all *related*.

 

Do you see a relationship here? And if so, what is the significance?

Are these patterns and shapes "intrinsic?" Well, sort of, but does that "intrinsicity" have meaning? Not really: its just math!

It is math but, never just.

What more is there than math that you see?

"Inevitable" in what sense? I'd argue that its not: it may be "highly likely" but that doesn't mean that you couldn't have a Universe with all the same properties as ours that never evolved any life!

Life is a property of the universe.:singer:

Its a property of *our* universe, but if your goal is to say that its "inevitable" given an infinite amount of time is a fallacy of probability: It may be highly improbable, but there is always a possibility that in an infinitely long instance of a specific universe, that tails will never occur in *every* coin flip forever. As a result, if this is your definition of "inevitability" then its not mathematically complete....

 

Life is a "property" of our universe, it is a definite "probability" in universes that share our own universe's physical parameters, but it is not by definition "inevitable," even given an "infinite" amount of time!

 

I'm pretty well versed in Chaos and Complexity, but I'm also painfully aware of the desire of the human mind to see common patterns and incorrectly infer linkages between them: that's a human trait that is extremely useful, but unfortunately sometimes highly misleading....

 

Keep going: I'm probably still missing something in what you're saying....

 

There is nothing in the dark that isn't there when the lights are on, :)

Buffy

[Thunderbird]

Yes, I agree. It is an assumption either way.

 

 

 

Perhaps, but I don't think there's any way to determine that.

 

 

 

 

There might be ways to measure it. :)

Causality must admit, dance with, court, marry and (pro)create with chance. Nigel Reading

.:singer:

[freeztar]

Well, if you think of a way, let us know. :)

[Thunderbird]

 

Life is a "property" of our universe, it is a definite "probability" in universes that share our own universe's physical parameters, but it is not by definition "inevitable," even given an "infinite" amount of time!

 

I'm pretty well versed in Chaos and Complexity, but I'm also painfully aware of the desire of the human mind to see common patterns and incorrectly infer linkages between them: that's a human trait that is extremely useful, but unfortunately sometimes highly misleading....

 

Keep going: I'm probably still missing something in what you're saying....

 

 

Here this is some great information on what I'm speaking about.

The whirlpool is robust or homoeostatic. It is called a stable attractor (Kauffman 1995, p. 187) because it is a stable form into which a dynamic system is attracted. Imagine a whirlpool around the drain in your tub. Interrupt the whirlpool by putting your hand in it and the water continues to drain, but not as a whirlpool. Remove your hand and the whirlpool reforms. Besides the whirlpool and the serpentine form, there are many other forms that a stream could assume but most of them are unstable. Whatever form the stream is placed into, it slides spontaneously into one of its few stable attractors and remains there.

 

 

 

A living creature

 

 

In biology we can trace the evolution of a dynamic system. Evidence comes both from the fossil record and from existing plants and animals. Because it only exists while energy flows through it a living creature is a dynamic system1. Like the evolution of a mountain stream, the evolution of a living creature leads to forms which represent principles of organization. This is proven by convergence in evolution. The snake is an example. Not all snakes are related because, at different times, several different groups of reptiles evolved the snake-form (Zug 1993, p. 119). It is an adaptation for penetrating through narrow apertures. A snake-like body-form also evolved independently in earthworms, in fish (the eel) and in mammals (the ferret). Thus the snake body-form is a principle of organization which has been rediscovered again and again by evolution. The wing is another example. It evolved independently in insects, reptiles, birds, and mammals. Holland (1995, pp. 27-8; 1998, pp. 229-31) discussed a further example, the principle of the camera-eye, which was discovered independently in the evolution of vertebrates and of squids and octopuses.

 

Holland is perhaps the foremost authority on the mathematics of self-organization and emergence. He warned against teleology. Different organisms do not evolve along convergent lines in order to attain the same end-point. Evolution is by chance.

 

Convergence refers to the similarity of agents occupying similar niches. With some knowledge of the niche, we can say something of the form of the agent that will occupy it (Holland, 1995, p. 169).

 

That is to say, given the air as an ecological niche, we can predict that many of the life-forms which colonize that niche will develop wings. Wings, therefore, are a pre-existing (predictable) principle.

 

In a dynamic system a principle of organization is not a static form like a triangle. Rather it is a dynamic, an ordered way for energy to flow. The whirlpool orders the energy of a stream, the snake- form organizes sinuous movement, the wing-form organizes flight, and the camera-eye organizes light to form an image.

 

The snake, the wing, the camera-eye, and many other examples of convergence prove that evolution fulfills pre-existing principles of organization. That the same possibilities are realized again and again at different times also proves that the total number of such principles is limited. Principles of organization are specific, unchanging, and limited in number.

 

You may object that there is no principle of organization, only an interaction between components the outcome of which is determined by their properties and by inherent constraints. Thus in the evolution of birds the properties of bone, muscle, feather, air and gravity interacted according to inherent constraints and the wing emerged from these interactions. But this objection misses the point. Insects and birds evolved independently. In the insect different components with different properties interacted under different constraints to evolve the same structure, the wing. The number of ways in which such components might interact is very large. Most of the structures formed, however, would not be functional. The few structures which could potentially function in movement represent the pre- existing principles of organization. These include wings, legs, the snake-form, tail-and-fin, and several others.

 

 

 

The brain

 

 

The brain is a dynamic system because it too only exists while energy flows through it. Like every other part of the body, the brain is self-organized. I explained earlier that the brain 's self-organization is directed both by the properties of the component parts (what fits with what) and by information from the environment. But self-organization is also directed by the inherent tendency of a dynamic system to adopt organized forms.

Maxson J. McDowell

[Thunderbird]

Well, if you think of a way, let us know. :)

This is some good info.on the subject enjoy.:singer:

D'Arcy Thompson:

ON GROWTH AND FORM

 

In this 1917 classic, D'Arcy Thompson provides a mathematical analysis of biological processes, especially growth and form. D'Arcy believes that natural selection has a limited function in evolution: it removes the "unfit", but it does not account for significant progress. D'Arcy believes that new structures arise because of mathematical and physical properties of living matter, just like the shape of nonliving matter. Form is a mathematical problem, and growth is a physical problem. The form of an object is the resultant of forces. By simply observing the object, we can deduce the forces that have acted or are acting on it. This is easily proved of a gas or a liquid, whose shape is due to the forces that "contain it", buit it is also true of solid objects like rocks and car bodies, whose shapes are due to forces that were applied to them. D'Arcy believes that living organisms also owe their form to a combination of internal forces of molecular cohesion, electrical or chemical interaction with adjacent matter, and global forces like gravity. The formative power of natural forces expresses itself in different ways depending on the "scale" of the organism. Mammals live in a world that is dominated by gravity. Bacteria live in a world where gravity is hardly visible but chemical and electrical properties are significant. D'Arcy investigates what physical forces would be responsible for the surface-tension that holds together and shapes the membrane of a cell, and then analogously for cell aggregates, i.e. tissues, and then skeletons. While his formulas have not stood up to experimental data, the underlying principle is still powerful: D'Arcy believes that genetic information alone does not fully specify form. Form is due to the action of the environment (natural forces) and to mathematical laws. D'Arcy was fascinated by the geometric shapes of shells and sponges and believed that their geometry could not be explained on the basis of genetics but would be explained in terms of mathematical relationships.

[freeztar]

This is some good info.on the subject enjoy.:)

 

Indeed. Although, I enjoyed the quote to Buffy more. Can you add a link to these please?

 

The first quoted article (to Buffy) deals with convergent evolution and homoplasy.

 

On a macro-scale, it would be feasible to determine the present day homoplasies (someone might have already done it?). The problem is that you cannot predict the future. If we had no knowledge of the pre-historic existence of dinosaurs, would we, in this present day, even consider their enormous forms a possibility in the world we live in? I doubt it. On a "micro"-scopic level you encounter a whole new realm of morphologies. For example, the wings of bats and birds serve the same purpose, but vary greatly in morphology and use.

 

In other words, convergent evolution does not predict morphologies, it explains them.

[HydrogenBond]

What I believe is the laws of nature form evolving patterns. If we start with a cloud of hydrogen gas and a star forms, we get higher atoms. If oxygen is able to form, we get water, etc. Every new star will do the same thing, in a general way, although the proportions have variability.

 

Knowing that the DNA is a molecule and this molecule is both very stable and is the basis for the genetic patterns of life it seems likely it is analogous to the star in the sense that it inevitably moves toward higher life. This doesn't correlate to existing theory, which takes the DNA out of chemistry and gives it no sense of direction beyond something random.

 

One way to look at it is the DNA contains potential. The human genetics contains enough potential to generate a very high life form. The genetics of worms has less potential and can only generate a worm. When male and female gamete cells combine the genes will shuffle to form one complete DNA. Depending on how they shuffle will determine the genetic potential that is given to the combined DNA. If the evolution is suppose to occur they will shuffle into a state of higher potential. The DNA is a chemical that follows the laws of thermodynamics. Evolution simply implies the DNA is gaining potential allowing life to have more potential.

[Buffy]

In other words, convergent evolution does not predict morphologies, it explains them.

 

The quote is interesting, but the point of my previous post is that its really seeing patterns where there are none. We think that all life must be carbon-based because we've never seen silicon-based life. All higher animals with eyes have fluid filled membranes with rods and cones because that was the proto-eye in the first species that developed it that we all have as a common ancestor.

 

Common ancestry of morphologies can go back to before the visible traits existed, at least as far as can be told from the sketchy evidence.

 

Where there is a "natural convergence" its still highly dependent upon the environment, and past DNA history may in fact limit adaptation. Look at wings: the Wright brothers went with wing-warping for control surfaces when extensible ailerons are actually far more efficient across a wider flight envelope. Birds DNA makes it very difficult to make that leap in morphology.

 

Worse, forward pointing wingtips are actually far more efficient and effective, but no animal has evolved a fast enough brain or found the ecological necessity for the stronger muscles required to manage this more complex and difficult design, even though it is optimal when taking into account *only* aerodynamic principles of our *particular* atmosphere.

 

In a similar vein, large increases in viscosity change the shape that is "optimal" in a "wing" which is why fins on fish are not warped.

 

That is, its not that there is some mathematically driven "optimal" or "intrinsically superior" morphology: it all depends on the environment.

 

Conversely, patterns re-appear all over the place, and have nothing to do with common provenance. There really is no similarity between the spirals of a galaxy--which are density waves--and hurricanes--which are moving structures. All of the physics of the two systems is entirely dissimilar. Because Fibonacci is such a fundamental and easily generatable sequence, its not in the least bit surprising that they both look like that.

 

Furthermore, it doesn't take much of a change that's either a random decision point or an environmental change to radically alter even where the local maximums are in a complex system, leading to radically different points of convergence.

 

While I agree that its possible--indeed, I argue *too easy*--to find points of convergence, I find a lot less significance in this than the author of that quote does.

 

The mark of our time is its revulsion against imposed patterns, :phones:

Buffy