Is Biological Evolution molded by a template defined by physical environment?
In quest of the reason why Darwin avoided using the word "Evolution".
by Bruce Cornet, Ph.D.
The name Darwin is considered by most people as synonymous with evolution, but in the Origin of Species the word "evolution" does not appear! Back in 1859 the word "evolution" had a very different meaning than what comes to mind today. Charles Darwin did not avoid using the word because he did not want to offend and incite the religious majority of his day. Rather, Darwin refers to the mechanism behind biological speciation as "descent with modification." He avoided using the word "evolution" because it did not convey the precise meaning he wanted. Ironically, the original definition of evolution implies a process more in keeping with Divine creation that is, destiny or predetermination, if you will!
Stephen Jay Gould in his most recent essay (Natural History, February 2000):
"What does the dreaded "E" word mean, anyway?" wrote: "Darwin, needless to say, did not shun "evolution" from motives of fear, conciliation, or political savvy but rather for an opposite and principled reason that can help us appreciate the depth of the intellectual revolution that he inspired and some of the reasons (understandable if indefensible) for the persistent public unease.
"Pre-Darwinian terminology for evolution -- a widely discussed, if unorthodox, view of life in early nineteenth-century biology -- generally used such names as transformation, transmutation, or the development hypothesis. In choosing a label for his own, very different account of genealogical change, Darwin would never have considered "evolution" as a descriptor, because that vernacular English word implied a set of consequences contrary to the most distinctive features of his proposed revolutionary mechanism of change."
"Evolution" comes from the Latin word "evolvere," which literally means to unroll or unfold in time. The Universal Dictionary of the English Language (Chicago, 1938) defines evolution as "an unrolling of a scroll, opening of a book." That dictionary also distinguishes between the original definition of the word and the biological definition: "The course of development by natural processes, as seen in the animate world of nature, whether it affects the growth of the individual organism or that of the species."
According to Gould (2000), "The Oxford English Dictionary traces the word "evolution" to seventeenth-century English poetry. Here the word's key meaning -- the sequential exposure of prepackaged potential -- inspired the first recorded usages in our language. For example, Henry More (1614-87), the British philosopher responsible for several of the seventeenth-century citations in the OED entry, stated in 1664, "I have not yet evolved all the intangling superstitions that may be wrapt up.""
The original definition of evolution, however, does apply to developmental biology: A vertebrate embryo expands or develops through a predetermined sequence of cell growth and cytosome changes to become an adult. A fern fiddlehead (immature or embryonic leaf) unrolls and expands to produce the adult leaf in accordance with fractal patterns of geometry. These examples of evolution are consistent with its original meaning the unfolding of preformed parts. Today we understand why organisms develop that way. The genetic code is the basis for predetermined (determinate) and predictable change. But such change has nothing to do with biological evolution through time.
Two very different meanings for the same word.
Ironically, the viewpoint of Creationists conforms to the original meaning of the word Evolution, in that the outcome was predetermined and not the product of random mutation and selection. In order to maximize the distinction between determinate and indeterminate evolution Modern Biologists and Geneticists have opted for an extreme definition, which excludes any hint of predetermination or Creationism. In doing so they have weakened their arguments and theory, not because there was some intelligence behind or pre-existing, exotic, or as yet undetected pattern to our existence, but because their exclusive reliance on randomness as the transforming process behind biological evolution has blinded them from recognizing an interaction between the two antagonistic definitions of the word, evolution: Random (selection) vs Predetermined (directed and limited by what is probable and efficacious, not by what is possible). The theory being developed in this essay is that the process is not completely random, but forced in predictable directions by limitations imposed by physics and chemistry. Darwin called that part of the process, natural selection.
Evolution is constrained by physics and chemistry
An example of a mathematical regularity of nature that emerges from
complexity is the number of petals of flowers. The majority of plants have a number of
petals taken from the Fibonacci series 3, 5, 8, 13, 21, 34, 55, 89. Leonardo Fibonacci
(circa 1200) recognized this progression of numbers in a study of rabbit population
growth. The view of conventional biologists is that the flower's genes specify all such
information, and any pattern is possible. However, there may be chemical constraints on
proteins, despite their coding by DNA. In other words, genes do not necessarily determine
everything (Stewart 1997).
And even if they do, they may do so only indirectly. For example, genes tell plants how to make chlorophyll, but they don't tell the plants what color the chlorophyll has to be. If it's chlorophyll, it's green - there's no alternative. So some features of the morphology of living creatures are genetic in origin and some are a consequence of physics, chemistry, and the dynamics of growth. One way to tell the difference is that genetic influences have enormous flexibility, but physics, chemistry, and dynamics produce mathematical regularities.
The numbers that arise in plants display mathematical regularities. They form the beginning of the so-called Fibonacci series, in which each number is the sum of the two that precede it. Petals aren't the only places you find Fibonacci numbers in plants. Higher order structures of the reproductive spike or inflorescence also demonstrate similar mathematical patterns. If you look at a giant sunflower, you will find a remarkable pattern of florets in its head - tiny flowers that eventually become seeds.
The florets are arranged in two intersecting patterns of spirals, one winding clockwise, the other winding counterclockwise. In some species the number of clockwise spirals is thirty four, and the number of counterclockwise spirals is fifty five. Both are Fibonacci numbers, occurring consecutively in the series. The precise numbers depend on the species of sunflower, but you often get 34 and 55, or 55 and 89, or even 89 and 144, all consecutive numbers in a Fibonacci sequence. Pineapples (Bromeliad family), for example, have eight rows of scales which slope to the left in diamond-shaped markings around its shape, and thirteen rows of scales which slope to the right another example of Fibonacci numbers.
The key question is this: If genetics can choose to give a flower any number of petals it likes, or a pine cone with any number of scales that it likes, why do we observe such a preponderance of Fibonacci numbers? The answer, presumably, has to be that the numbers arise through some mechanism that is more mathematical than arbitrary genetic instructions. The implication is that if life evolved over again on Earth, similar patterns of plant parts would evolve again due to factors beyond genetic control.
Strategies for animal movement are constrained by physics and chemistry
The ocean, land, and air provide tactical problems for organisms that want to travel through these media. If one examines medium to large organisms that have adapted to movement through water, we find similar strategies: Long fusiform body shape, fins and flippers, adaptation to the crushing forces of water at depth, and sensory location of objects and food in low levels of light. Animals that became adapted for movement on land through the development of limbs for walking have returned to the ocean numerous times during the last 300 million years: Among reptiles are the Ichthyosaurs, Plesiosaurs, and Mosasaurs of the Mesozoic Era. Among Tertiary mammals are the whales and dolphins. Among birds are the penguins. Their convergence in body form and fins is an example of how the physics of locomotion in water places severe constraints on what is possible.
Locomotion through air places even more constraints on body form and appendage shape. All animals that have become adapted for gliding or powered flight have had to develop appendages that conform to aerodynamic laws. Their bodies had to evolve methods to reduce weight, such as hollow bones in birds. During the last 300 million years several independent branches of evolution converged on similar body forms: For powered flight among reptiles there are the Pterosaurs and birds of the Mesozoic Era. While Pterosaurs evolved a large bat-like membrane of skin for a wing, birds modified a pre-existing feather-like down, which may have evolved originally as 1) a form of insulation, 2) for use in body language, or 3) as camouflage. Metabolic changes (exothermy) also had to evolve which would supply the additional energy needed for powered flight. Among Tertiary Mammals there are the bats, which evolved very early in the Tertiary so early in fact that some paleontologists suspect that their ancestry may go back before the extinction of the dinosaurs. Insects evolved flight long before reptiles or mammals, but they too had to evolve appendages which could propel them in controlled flight.
If water and air can place such extreme restrictions on evolution, why would locomotion on land be any different? Insects, because of their exoskeletons, small size, and segmented bodies, evolved more than two pairs of legs. But animals with endoskeletons evolved only two pairs of legs. This difference may have more to do with energy requirements than with how the nervous system evolved, muscular-skeletal complexity, innervation (nerve supply) and coordination, and support of body weight. Insect legs by comparison are like robotic arms they have localized motor controls, not massive and extensive muscle systems which require much more energy to operate. Land animals with six legs would require 50% more energy (ATP) than would animals with four legs (muscles eat up ATP). Thus, land animals with endoskeletons and two pairs of legs are evolutionarily favored.
Why couldnt large insects evolve, as depicted in the Hollywood movie, Starship Troopers? Exoskeletons become a major weight problem with size increase, and muscle size could not increase without also adding to that weight burden. Thus, there is a limit to insect size, which is again constrained by physical factors such as gravity. Larger insects might evolve on smaller planets, but not on planets the size of Earth or larger. Giant millipedes evolved during the mid-Paleozoic some 370 million years ago when land predators did not exist. They reached a length of tens of feet and probably hundreds of pounds. They were able to move on land because their bodies were supported by hundreds of short stubby legs, which effectively distributed their weight. Once predators capable of finding such slow-moving banquets evolved, these giant millipedes quickly became extinct and could not evolve again from their tiny cousins.
For whatever reason, competition in IQ does not seem to have been a significant factor between predator and prey in the dinosaur world, because brain size remained relatively small, even for those Carnosaurs with the largest brains. However, that is not the case with mammals. If one studies brain size based on brain cavity size over the last 65 million years, one will find a progressive increase both in predators and prey. The most likely explanation for this trend is that IQ did play a significant factor in prey outsmarting predator and predator outsmarting prey. Competition favored increasing intelligence as a strategy for survival. The evolution of brain size and complexity reached its climax in Primates and us.
Why did mammals evolve differently than dinosaurs? Perhaps because during the Mesozoic mammals had to be more intelligent than their reptilian predators in order to survive, so a mechanism for increasing intelligence evolved. Brain size did not increase much for Mesozoic mammals because mammals did not require much intelligence to outsmart their reptilian prey. On the other hand, when pitted against predator and prey of their own kind, competition for increased IQ was necessary.
Bipedal locomotion is not the most effective method for speed in outrunning faster four-legged predators. Try running against a horse or running from a cheetah. Freeing and modifying the front legs in Primates for use in grasping and climbing not only reduced survivability on land, but forced Primates to become smarter than their claw-bearing predators who could climb trees. Thus competition between predators and prey continued to climb into the canopies of trees. But when one lineage of Primates began to spend more time on the ground than in the trees, perhaps because climatic changes forced them to find alternative methods for survival when savannas and grasslands replaced jungles, increased evolutionary stress on IQ and brain development occurred.
Like water and air, which place constraints on forms of locomotion and survival in those media, climate on land places its own set of constraints on survival. Would primates (or something similar) evolve again if we could turn back the clock 65 million years? Given the gradual trend in world climate from near pan-tropic conditions from equator to poles in the Cretaceous to glacial conditions in the recent past, and the trend in increasing aridity with desertification of vast areas near the equator, something similar to Primates might evolve again. But the real question is whether a species as intelligent as Homo sapiens sapiens would evolve again. There is no way of knowing or predicting that outcome.
But what is known is that our kind of intelligence and tool-making capability evolved because of various climatic and edaphic trends set in motion at the end of the Cretaceous. The fossil record and extant species have also shown that species which became adapted to flight or to living in water did not become toolmakers, because their appendages were limited by adaptation to locomotion in those media. Some birds can use branches as tools, but must do so with their feet, while some cephalopods (e.g. octopus) can be trained to use simple tools in simple ways. Brain size is not limited in water, although it is limited in air due to weight constraints imposed by flight. Cetaceans have brains as large or larger in proportion to their body mass than humans. Dolphins, for example, can be trained to use tools with their mouths, but in their natural water world they do not have any need for tools.
However, only land bipeds who evolved the ability to grasp and examine objects up close with binocular vision evolved advanced tool-making capability and the intelligence that goes with it. If there is a correlation between these features based on constraints and parameters imposed by the physical medium, then there is a high probability that intelligent toolmakers will evolve only on land and in an air-breathing bipedal species. The exception might be an amphibian or animal adapted to both land and water, but that would still require the evolution of appendages which could make tools, and binocular vision, something that whales and dolphins do not have.
What this boils down to is simple: There is a high probability that any biological (organic-based DNA) life form that has reached a level of intelligence and tool-making capability similar to humans will be humanoid in shape, regardless of its planet of origin. Some of what Hollywood Sci-Fi movies (e.g. Close Encounters of the Third Kind, Star Wars, ET) and television series depict (e.g. Star Trek, Voyager, Deep Space 9, etc.) may not be that far removed from possibility. In other words, some extraterrestrials whose technology and intelligence allowed them to explore space might look like us, but not because of any common ancestry or common origin. In biology we call this phenomenon convergence, which is neither random nor due to chance. It is due to constraints imposed on adaptation by specific environments, physics, and chemistry.The Paluxy River footprints and tool artifact found in Albian (mid-Cretaceous) strata of Texas not only point towards this possibility, but indicate that Earth probably has been visited by humanoid astronauts in the very distant past (95 m.y.a.).
God did it?
Recently viewpoints among those who study reports of alleged alien abduction (the ETI kind) have shifted or become skewed towards a pseudocreationist or Creationist viewpoint, largely because Contactees and Abductees have reported similar encounters with humanoid entities allegedly from other worlds, some of whom are superficially indistinguishable from Homo sapiens. In other words, the concept of humans being 1) created elsewhere and brought to Earth, or 2) being hybrid descendants of space brothers (e.g. Lloyd Pye thesis), or 3) the similarity between some ETs and humans being evidence of a common origin - has gained favor among those unfamiliar with the vast amount of fossil and genetic evidence, which supports Biological Evolution of our species here on Earth (Cremo & Thompsons "Forbidden archeology" notwithstanding).
This has led to statements such as:
"For too long the Theory of Evolution has been taught as fact and as an undeniable truth. Scientists and educators have taught with fervor and passion that all life originated on Earth. Obviously there is some evidence that species change to adapt to the situation around them. But it is a giant leap of faith to assume we all came from some primeval ooze and gradually developed into complex life forms. I have had the luxury of seeing the complexity of just one cell. It is doubtful that life happened by chance. The logical conclusion is that there was a Creator. I receive many letters from scientists who claim to be experts in the field of genetics, who admit they are afraid to speak up. They are frankly afraid of losing their jobs, if they verbalize their own findings that the Theory of Evolution is in error." (THEORY OF EVOLUTION MINDSHIFT, Filer's Files #06 -- 2000, MUFON Skywatch Investigations, George A. Filer, Director, Mutual UFO Network Eastern February 12, 2000, Majorstar@aol.com (609) 654-0020 Web Site at www.filersfiles.com. -- Chuck Warren Webmaster.)
Biological Evolution has not been taught as an undeniable truth. It has been taught as a theory based on scientific observation using the scientific method. It is not a blind faith either, because it is still a theory despite the overwhelming body of data which support it. If it were proven beyond all doubt, it would be called the Fact of Evolution, not the Theory of Evolution.
Scientists, however, have not been able to break completely free of personal beliefs (more appropriately called biases or prejudice), which has given the public the opinion that they unquestioningly accept all the tenets currently included in the Theory of Biological Evolution. As a scientist I do not accept as fact all of those tenets. I have found too many exceptions to the rules, but that does not mean that I have disproved the general concept of Biological Evolution.
The same can be said for religion, because no one has provided data, which supports a Theory of Creationism. That would be like saying that God made a video of Himself creating Earth and its varied life forms, and that someone discovered it in a newly discovered Essene cave on the edge of the Dead Sea.
The fossil record shows that life (as simple bacteria and cells) did not originate once on Earth, but perhaps as many as six times in the first 500 million years of Earth history, being wiped out by asteroid impacts again and again (Schopf, 1999). Only after frequent asteroid bombardment stopped - as safe paths were gradually carved out in the original helter-skelter of asteroid fields by the planets of our solar system - did life continue without major interruption (if one discounts the five extinction events in the last 510 million years).
Filer claims to have received many letters from geneticists who cannot accept that the genetic code evolved through random mutation and descent with modification through natural selection. The problem, however, should focus on currently held assumptions and explanations (interpretations) about what is known compared to our potential ignorance.
Adaptive Radiations and Punctuated Equilibria
If one looks at empirical evidence (all that life is capable of producing based on what it has produced), knowing the basics of biochemistry and genetics is not enough. Many functions and routines in the genetic code are poorly understood. Many genetic programs are rarely activated because their function is highly specific and dependent on critical triggers. When they are activated, what we sometimes see are miracle cures or rapid biological changes. The genes responsible for such programs may have evolved over tens of millions of years where selection favored their creation only under very specific life-threatening conditions.
We now know most of the basics about how biochemistry works, how DNA is replicated, translated, and transcribed, and how the various types of RNA function in the creation of proteins, lipids, sugars, steroids, enzymes, nucleic acids, and other necessary chemicals of life. But we do not yet know how a species of plant or animal can rapidly evolve into other species without controlling the necessary changes in genetic code which are required. The Theory of Biological Evolution is still limited by our ignorance about mutations, which are thought to be random and unpredictable. So how can a process which is inherently unpredictable result in rapid biological evolution according to the model of Punctuated Equilibria? How can the millions if not billions of beneficial or non-lethal mutations required for an Adaptive Radiation occur almost "on demand" and in a time frame well inside (less than) what is required for random mutation, selection, and reproductive rate (typically annual)? Surely, if any process recognized in the Theory of Biological Evolution lends itself to implication of Creation, this process does. But just because we do not understand something according to current theory, does not mean that we can invoke the concept of Divine magic. Even if God did create life in the beginning, and then tweaked it along the way, He had to do it according to laws of physics and chemistry, which are subject to detection, analysis, and understanding by humans.
Perhaps the only article of absolute faith in science is the one which states that the laws of physics are inviolate until proven otherwise. If a violation can be proven, a new law must be added and/or the old law modified, whereby the laws of physics again become inviolate.
The two most notable examples of Adaptive Radiations in the fossil record are the evolution of flowering plants (angiosperms) in the Early Cretaceous and the evolution of mammals following the demise of the dinosaurs at the end of the Cretaceous. In neither case did these radiations begin from an Adam-Eve scenario, or from little biological diversity to extreme biological diversity in a period of five to ten million years. In both cases there was a long preadaptive phase for angiosperm and mammalian ancestors that can be traced back hundreds of millions of years to the Late Triassic Period. But what could have been occurring during those early phases that allowed for rapid evolution or Punctuated Equilibria? Why did these phases leave such a poor fossil record with many gaps in fossil data during the Triassic and Jurassic periods?
With the advent of computers and Cladistic Analysis, or the recognition and comparison of plant and animal clades or groups, came a robust and data-rich method for analyzing evolutionary patterns. Because humans tend to be subjective in their analysis of evolutionary lineages, focussing on a small set of characteristics that they weigh more heavily than others, cladistics looks at as many character states as possible, giving some of them weighted preference in order to test various evolutionary trees that result from number crunching by computers. Those trees with the fewest steps or branches in them are considered the most parsimonius or likely.
Out of cladistic analysis came the recognition of evolutionary reversals, or the reappearance of characters which appeared earlier in time, seemed to disappear in descendants, only to reappear in one or more branches on the evolutionary tree much later in time. If character reversal does not represent the coincidental re-evolution of a look-a-like character state, the implication is that the gene or genes responsible for that character were never lost. Instead they were archived and suppressed, but not destroyed or modified. Later on in time these archived genes became reactivated and expressed again.
Any organism that has the ability to archive and retain old sets of characteristics, which can be reactivated if and when a set of specific environmental triggers occur, would have a decided advantage over an organism that had to completely re-evolve those characters in order to survive. Because the reactivation of certain suppressed character states may require the re-booting of the organism (reproduction with subsequent expression occurring in the offspring), their re-expression would be tied to changes that occur during gamete production, maturation, and competition. Under stress the organism may produce chemicals and hormones that aid in reactivating suppressed genes, while suppressing complementary expressed genes.
Evidence in favor of this theory comes from the extinction rate and subsequent recovery of plants and animals after major extinction events. The Permian extinction is perhaps the worst one that occurred in the Phanerozoic (last 510 m.y.), because nearly 99% of all species on this planet disappeared in a geologic instant. It took nearly the entire Triassic Period (208 m.y.a. to 248 m.y.a.) which followed for plant and animal diversity to recover - a period of 40 million years.
The next major extinction event occurred at the end of the Triassic. Nearly 98% of plant and animal taxa in the American continents disappeared in a geologic instant at the Triassic-Jurassic boundary. It took the entire Early Jurassic Epoch (188 m.y.a. to 208 m.y.a.) for plant and animal diversity to recover - a period of 20 million years.
Cramer (1986, The Pump of Evolution) presented a most intriguing hypothesis that mass extinction events from asteroid impact act as an evolutionary pump, and are coupled with increases in evolutionary rate called Punctuated Equilibria. In the mid-Cretaceous the angiosperms or flowering plants underwent their primary radiation. That is, beginning in the Early Albian flowering plants begin to appear in the fossil record in sufficient numbers that they are found at many localities around the world. Before the Albian only traces of angiosperm fossils can be found. This Albian explosion in diversity (i.e. adaptive radiation) does not appear to be preceded by a major extinction event. It is possible that an impact event occurred, but was not destructive enough to kill off many species. Instead, it disrupted enough ecological niches through climatic change that flowering plants had their long-awaited opportunity to increase their numbers by filling vacant niches.
The third major extinction event occurred at the end of the Cretaceous. Only about 60-70% of the plant and animal species became extinct. Extinction favored animals with large body masses, such as the dinosaurs, but many sea creatures also disappeared, such as ammonites. Plant and animal diversity recovered rapidly with the radiation of mammals and the fruits and plants upon which many of them fed. That recovery is essentially covered by the Paleocene Epoch (54 m.y.a. to 65 m.y.a.), or a period of about 10 million years.
The fourth major event (due also to a giant asteroid impact called the Chesapeake crater off the Carolina coast) occurred in the Eocene (38 m.y.a. to 54 m.y.a.), which followed the Paleocene. There is very little evidence of mass extinction following this impact, implying that plant and animal taxa were able to survive with minimal loss of diversity. Recovery occurred in about 5 million years.
Implication: Plant and animal species have evolved gene mechanisms for survival under extreme environmental conditions, and are more able now to recover from large asteroid impacts, massive volcanic erruptions, and other life-threatening changes than ever before. If you have noticed, the time of recovery halved from the previous event. That would mean that our planet might be able to recover from another giant asteroid impact in about 2.5 million years or less, compared to 40 million years in the Triassic Period.
But wait! Two million years ago marks the beginning of the Pleistocene, or Glacial Period. An extinction event occurred then also as major climatic change accompanied the expansion of polar ice caps. Recovery during various glacial events was slow. It was not until the end of the last Wisconsin glaciation that recovery could accelerate.
However, another extinction event occurred following the last ice age about 12,000 years ago (beginning of the Holocene Epoch) when the retreat of huge ice sheets caused massive rebound of the crust as the weight of ice was removed. Major Earth changes resulted, which include increased volcanic activity accompanied by earthquakes. The big mammal faunas experienced a rapid decline at this time, with subsequent extinction. These extinctions, however, are thought by many paleontologists and anthropologists to be the result of over-hunting by humans, and not due to the Earth changes. Whatever the cause, this latest extinction event and recovery are associated with the rise of Homo Sapiens to world dominance.
One characteristic which distinguishes humankind from other primates is genetic diversity. That diversity is an expression of humankind's ability to adapt genetically to many different climates and environments. Physical and physiological diversity are our strength, not our weakness. This diversity provides us with more possibilities or strategies for survival, given the uncertainty of natural selection. Any reduction in that diversity moves Homo Sapiens closer to the precipice of extinction.
Only those groups of plants and animals which had evolved the ability to archive and utilize old genes in order to create rapid biological diversity would benefit from such extinction events. And that diversity would be of their own internal design.
Cremo, Michael A. and Thompson, Richard L., 1994. Forbidden Archeology, the hidden history of the human race, Bovardhan Hill Publishing, Badger, CA, 952 p.
Gould, Stephen J., 2000. What does the dreaded "E" word mean, anyway? Natural History, February, pp. 28-44.
Schopf, J. William, 1999. Cradle of Life, the discovery of Earths earliest fossils. Princeton University Press, Princeton, NJ, 367 p.
Stewart, Ian, 1997. Natures Numbers, the unreal reality of numbers. Basic Books, 176 p.
Bruce Cornet, Ph.D.
Copyright B.Cornet 2000
Date this page was last edited: 05/01/2007