Macro- vs. Micro-Evolution
- If there are general objections to evolution, is there any part of the theory—specifically by hard evidence—that is demonstrated to 'work'?
- What are examples of evolution in real time?
- Are there specific causes that drive microevolution?
Everyday there are new developments, discoveries, and remarkable surprises coming from science. Research in the public and private sector have reached into the cell, the DNA, into the information base of life. While humans can use the new science to make for medical remedies, none of this has revealed the seamless explanation for evolution. In fact many of the discoveries reveal evidence that conflicts with an evolutionary story to life's origin. Stepping back in time, in Darwin's day, the research that touched on use of the information of life was an entirely different enterprise. Breeders selected traits to domesticate plants and animals. They achieved specific results as successive generations were produced. Barley, corn, dogs, cattle, pigeons, sheep, wheat, and many other examples yielded the benefits to this human-directed breeding process.
In the wild, and what caught Darwin's eye, nature seemed to be doing something similar. Various organisms with many similar species occupied many different niches in the ecosystem. We are often reminded how Darwin observed some dozen finch species living across the different Galapagos Islands. He assumed, as with domestic breeding, that some ancestral finch population evolved over time to give the numerous species he was able to see during his visit to the Galapagos. Some selection process akin to the action of a breeder was at work here. Yet, his conclusion was more assumption than observation. Recent work—within the past several decades—has finally come to prove species arise from species. In this case, a finch species gives rise to another finch species—but this is not a random ongoing process as much as it is a response to prevailing environmental conditions. This is now documented, even by research on the Galapagos Islands. And yet, the community of Darwinian evolutionists herald the work as an example of macroevolution at work (i.e., in support of the standard story).
The short answer is one of keeping a focus. Think about and perhaps even agree that microevolution works, and over short timeframes, but that macroevolution fails (see definitions of macro- and microevolution in text below). Plant and animal breeding in fact reveal examples of intelligence at work in directing microevolution, much like the environment pressures the appearance of a different type of finch on the Galapagos. Most importantly, we are going to look at what works and why. This is careful consideration and thus not a blanket critique of evolution. This is an important point, one that allows us to discern truth in light of popular conceptions that may in part contain fictions. The following discussion simply places a few more issues into the window's view and this helps in our endeavor to build perspective on perspective. At some point the larger picture emerges with clarity.
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Defining terms helps to set the stage. Dr. Spetner, as well as many others, make the following distinction:
There are two terms and that I shall use often. They are a microevolution and macroevolution. Microevolution is a small evolutionary change. It can sometimes lead to a new variety or a new species. Macroevolution is supposed to be a large change in a population. A macroevolutionary change can lead from one major group to another, such as from a fish to an amphibian or from a reptile to a bird. The attraction of The Origin was its promise to account for macroevolution. Spetner (NBC) Page 67
Dr. Denton agrees and in his writings from earlier in the mid-1990s we see a focus on how evidence for one aspect of evolution serves to highlight the lack of support for the standard story as a whole.
Since 1859, a vast amount of evidence has accumulated which has thoroughly substantiated Darwin's views as far as microevolutionary phenomena are concerned. Evolution by natural selection has been directly observed in nature, and it is beyond any reasonable doubt that new reproductively isolated populations—species—do in fact arises from pre-existing species. Although some of the details of the process are still controversial, and certain aspects of the modern view of speciation differ slightly from Darwin's, it is clear that the process involves a gradual accumulation of small genetic changes guided mainly by natural selection.
The very success of the Darwinian model at a microevolutionary level, and particularly the mode of its success—by rigorous empirical documentation of actual evolutionary events and thoroughly worked out models showing precisely how the process of speciation and microevolution occurs—only serves to highlight its failure at a macroevolutionary level. Denton (ETC) Page 344
We can be a little more specific here. Dr. Spetner's writing (see Not by Chance) actually focuses on a proposal whereby the environment is a driving force behind the appearance of new species. He notes this is a nonrandom driver making for the form of evolution that is observed by science. His thinking is not entirely novel, he is simply reflecting a position that comes from observations scientists have made in a number of areas—from microbes to higher organisms. The prevailing thinking about macroevolution often confuses the issue and stops short of discerning macro- from microevolution. It will take a shift in thinking to embrace the difference with a wholly public acknowledgment. This means a rewrite of textbooks and a shift in view—perspective building in short will open a new discussion and shed a new light on the way evolution is researched and reported.
Darwin's Finch Studies
One noteworthy example that is not often interpreted in light of the difference in macro- and microevolution as highlighted here... is the work of Peter and Rosemary Grant (see The Beak of the Finch: A Story of Evolution in Our Time by Jonathan Weiner). Weiner's book is branded with the words: "Evolution in the flesh, a landmark in evolutionary studies — The Los Angeles Times." The Grants while working on the Galapagos Islands have indeed observed morphological and species differences in finches in response to, among other things, variations in the environment and food supply. Such is also the content of a PBS television special on their work. What we want to emphasize is this all works well in the context of microevolution. The scientific community as a whole may declare this as evidence in support of macroevolution, but this is the problem of making a leap from the micro- to the macro-concept of evolution.
Darwin's leap was only a guess, for which he had no evidence. Because macroevolutionary changes need long time spans he could not have had evidence for it. Even today we have none. Was Darwin, and the neo-Darwinians with him, right in suggesting that a large change is built up from many small changes? Spetner (NBC) Page 75
Let's keep an eye on Dr. Spetner's question of making the leap. Let's also acknowledge that even Darwin wrestled with where the evidence seemed to lead...
The fact is that the evidence was so patchy one hundred years ago that even Darwin himself had increasing doubts as to the validity of his views, and the only aspect of his theory which has received any support over the past century is where it applies to microevolutionary phenomena. Denton (ETC) Page 77
Again, being brief in making a point may appear stilted. There are many examples of microevolution to examine. Even Dr. Denton makes this point among the numerous examples that he includes in his book. So, beyond finches or domesticated organisms we acknowledge that you can find other examples, including:
Insect evolution in Hawaii has been particularly spectacular. There are about 4300 species of insects unique to the Hawaiian Archipelago and these appear to have descended from about 250 original colonizations. Denton (ETC) Page 82
Of Domestication And In The Wild
Human breeding of animals and the shifts in finch species are not demonstrating new phyla appearing from other parent phyla. The finches produce new finch varieties or species and that's it. Breeders using conventional breeding and selection techniques end up with cows from cows and dogs from dogs, and that's it. They are not driving change up the tree of evolution nor creating new branches with novel and different endpoints. The real test is by taking the bred organisms and then pooling them together ... where one again sees the reappearance of the wild type—that is, a common mutt would again reemerge from the segregated breeds of dog. That would be turning back to a point of origin for the dog breeds. This demonstrates a kind of genetic plasticity that is being worked within what one can see in dogs, but again not the derivation of a new species outside of that pool of plasticity of dog breeds. This is a simple argument for a more complex picture, but the illustration is helpful at this point.
On Rapid Change
Dr. Spetner goes on to indicate the 'newer' neo-Darwinian (NDT: neo-Darwinian Theory) thinking in support of the standard story encounters problems.
In recent years, some biologists have pointed out what they hold to be a serious problem with the gradualness of the NDT. They find fault with the thesis that macroevolution is made up of long chains of many small steps. Some have suggested that the gaps in the fossil record are real, that there really were abrupt changes in animals in the past. They claim that most evolution is made up of large abrupt changes [Eldredge and Gould 1972, Gould and Eldredge 1977]. They hold that populations remain in unchanged equilibrium for long spans of time that are punctuated by large abrupt changes. They have called their theory Punctuated Equilibrium. They hold that macroevolution is not just an accumulation of many small steps. When they first proposed their theory they held a that large changes are qualitatively different from the small ones. Macroevolution consists of large abrupt changes [Gould 1980, Stanley 1979].
More recently, some punctuationists have changed their minds. They have returned to the Neo-Darwinian fold and hold that macroevolution occurs not through jumps, but through cumulative selection. But they differ from the neo-Darwinians in that they hold that macroevolution could occur in smaller populations and in fewer steps than had been previously thought [Eldredge and Gould 1988, Maynard Smith 1988]. The continuous changes only appear to be jumps in the fossil record. Spetner (NBC) Page 68
Dr. Spetner coins terms to describe the two schools of thought on evolution—one being 'brady' for those that hold evolution is a gradual process over much time and 'tacky' for those who see dramatic jumps or rapid appearances in life forms. Dr. Denton, in his book (see listing for Evolution—A Theory in Crisis) does an excellent job of working through a number of issues to the point of making the following points:
The discussion in the past three chapters indicates that the facts of comparative anatomy and the pattern of nature they reveal provide nothing like the overwhelming testimony to the Darwinian model of evolution that is often claimed. Simpson's claim that " the facts simply do not make sense unless evolution is true" or Dobzhansky's that "nothing in biology makes sense except in the light of evolution," are simply not true if by the term evolution we need a gradual process of biological change directed by natural selection.
It is true that both genuine homologous resemblance, that is, where the phenomenon has a clear genetic and embryological basis (which as we have seen above is far less common than is often presumed), and the hierarchic patterns of class relationships are suggestive of some kind of theory of descent. But neither tell us anything about how the descent or evolution might have occurred, as to whether the process was gradual or sudden, or as to whether the causal mechanism was Darwinian, Lamarckian, vitalistic or even creationist. Such a theory of descent is therefore devoid of any significant meaning and equally compatible with almost any philosophy of nature. Denton (ETC) Page 154
All this touches lightly on points that are addressed in more detail elsewhere in the WindowView feature articles. But making these declarations is important. Take this opportunity to recognize the concept of evolution embodies evidence and critiques, both an indication that the theory is neither simple nor a done deal. That is, science plays a role in discerning something important here. All this goes to defining what is known about origins and the evolution that supposedly follows as a natural process stemming from the origin of life. Yet, as noted before the starting point and conditions making life possible do not get evolution up and running as is often assumed. Later you can touch on perspectives that include consideration of the environment, the way organisms are classified, how complexity of cells, and even the concept of design help to further differentiate where evolution fits in a proper context.
Before we move on, let's briefly touch on an important point concerning information. In the short answer above there is an indication that humans (breeders) and environmental drivers serve to force selection and thus drive microevolution. Both work with an existing base of information. New information may not be coming into the species, yet we can see an expression of some pool of information and ultimately see a new species produced. Information within a population (a single species) as opposed to adding large amounts of new information to make the dramatic shifts or appearances noted above is a key issue. Dr. Spetner notes this as follows:
Any theory meant to explain how all plants and animals evolved from a single cell has to explain how all the information got into the genome. All living organisms have a lot of information in them. You can gain some idea of how much information is in an organism both from the size of its genome and from the complexity of both of the organism's structure and its function. Information and complexity go hand in hand.
According to the doctrine of evolution, all the information in life today was built through evolution. If the neo-Darwinians think there mechanism can explain how evolution took place, they have to show how that mechanism could have put large amounts of information in to the genome. They have to explain how the genomes got all the information they have.
According to the bradys, the information in the genome builds up slowly over a long time through long chains of small evolutionary steps. Spetner (NBC) Page 70
We are reminded that the neo-Darwinian Theory works through selection to add information. So, if a mutation is good, the result is positive and a trait is preserved. If negative, then the trait is lost. Complicated mutations or sets of mutations require being 'all correct' to pass through the selection process.
A key factor or contribution if you will is Darwin's idea that one can make a logical link from microevolution to macroevolution. But let's call that a leap of faith based on the idea that gradual descent takes many small steps over a long period of time. That was Darwin's thinking on how evolution works. So, positive mutations are applied to a population making a step that holds for following generations. If enough positive steps come along, and stay within the population (not lost along the way!), then according to Darwin that's what makes for the bigger changes over time.
Neither of the two fundamental axioms of Darwin's macroevolutionary theory— ... continuity of nature ... and the belief that all the adaptive design of life has resulted from a blind random process—have been validated by one single empirical discovery or scientific advance since 1859.
Since the birth of modern biology in the mid-eighteenth century, nearly all advocates of the continuity of nature have attempted to explain away the gaps in terms of what ultimately amounts to some sort of sampling error hypothesis. Very few professional biologists have adopted the alternative nominalist position and explained them away as convenient and arbitrary inventions of the mind.
While it may have been the anti-evolutionists who, in perceiving the enormity of the empirical challenge posed by the existence of breaks in the order of nature, coined the phrase "missing links", it has been the evolutionists who have acknowledged their existence, who have sought them with such persistence. Denton (ETC) Page 345
So what resolving power do we have? If we go beyond the assumption that gaps will be filled as more information is collected, then what do we see as more information comes in? If evolution theory is correct, then we should see trends toward narrowing gaps in both data and our understanding of evolution. A continuum of life forms would then reveal the graceful transitions through gradual descent. And of course scientists have not been idle since Darwin's time. So are gaps closing is the trend there?
On the contrary, the gaps are as intense today as they were in the days of Linnaeus, and almost every major advance in biological knowledge, from the founding of comparative anatomy and paleontology in the eighteenth century to the recent discoveries of molecular biology, has only tended to emphasize the depth and profundity of the great divisions of nature. Denton (ETC) Page 346
If these gaps are part of the origin story, then there is an obvious need to bring in other evidence that would help to reasonably explain why jumps, leaps, discontinuities, and gaps exist. Perhaps the materialist mind is not suited to accepting a picture that has to be filled in from a number of perspectives to arrive at a working explanation. Indeed why doesn't the evidence just fill in the bare spots... unless those are themselves not gaps but some unique aspect of reality.
Early on, at your point of arrival to the Welcome pages of WindowView, you might have noticed we mentioned addressing 'uncomfortable' or 'difficult' questions. We are all too often anticipating information to simply explain and resolve issues we encounter. But the evidence for origins comes like a puzzle and a riddle combined. Some pieces fit together, others seem missing, and other science related approaches come to suggest something outside the standard story. As such the outsider proposals get challenged as not being science. Admittedly, such a mix makes for debate and uncomfortable territory. But again, while we are not looking for a final resolution to any debate (e.g., on evolution or creation), we see potential for something extraordinary. That keeps the floor open for further discussion. Later on we will address those 'outsider proposals' that are being challenged by the 'main stream' community of scientists and educators.
Quotations from "Not By Chance" (NBC) written by L. Spetner, are used by permission granted by Dr. Lee Spetner.
Quotations from Dr. Michael Denton's "Evolution: A Theory in Crisis" are used by permission of Adler and Adler Publishers Inc., 5530 Wisconsin Ave, Suite 1460, Chevy Chase, MD 20815
Writer / Editor: Dr. T. Peterson, Director, WindowView.org