Category Archives: Evolution

Objective and Collective Theories of Evolution

In reading modern discussions of evolution, and in various discussions, it has become clear to me that there is a difference between what I view as evolution theory, and what that label has come to mean in popular usage.  Reducing evolution to its fundamental and necessary principles, it requires the following conditions:

(1) Organisms that are capable of reproduction, and of passing traits to their offspring
(2) Organisms that may cease to exist (“die”) prior to their reproduction
(3) Competition among organisms for resources or conditions required for survival (at least until reproduction)
(4) Variability in traits between individual organisms, due both to inheritance and random occurence (“mutation”)

Evolution is loosely defined as “survival of the fittest”.  More carefully defined, it is the progression of the probability distribution of traits among a reproducing population of organisms which meet the four conditions described above.  The key to the qualitative progression of the distribution is the adversity to survival implied in condition (3), though each of the other conditions is necessary.  Using this definition, there can be no debate about whether evolution occurs – it is a mathematical consequence of this combination of conditions. 

Note that in this definition of evolution, the concept of “genes” does not occur directly, only the transmission of traits from generation to generation.  This is not to say that the modern theory of DNA genetics is invalid – it is a scientifically established fact that this is the mechanism for trait transmission in known life forms – but it is not an essential characteristic of evolution.  Also, note the absence of the concept of species.  The identification of species as a class of organisms that can mutually reproduce remains a useful definition, but it is not a dominant factor in evolution.

Any discussion of evolution as defined above is going to center on the progression of the probability distribution of traits in the population of individual organisms.  However, it is very easy to lose sight of the fact that this probability distribution is not a primary entity – it is derived only from a group of individual organisms, and has no existance or behavior apart from that of the individuals.  Nonetheless, efficiency in discussion is going to lead to the use of words such as species and genes to represent the aspects of the distribution of traits, and attributes will come to be assigned to these collective concepts.   This can, and almost always will, lead to a confusion of language in which the genes and species will be understood as primary actors in the evolutionary progression.

Current discussions of evolution often start at this point of confusion.  Species are said to evolve, genes are said to be acting in their best interest, to ensure the survival of the “gene pool”.  No attempt is (usually) made to tie these abstractions back to the actions of individual organisms.  The collective concepts become the entities to which the theory is applied, not only as a efficiency in discussion, but in the meaning to be projected in the discussion.  It is my assertion that this results – intentionally results – in a very different set of logical consequences than is implied by the original theory of evolution. 

The modern discussion of evolution is a discussion of the behavior of collectives, in which the value to be preserved is the perpetuation of the existance of the collective (gene pool or species).  Anthropomorphic terms are applied to both the genes and species – the genes have a “goal” they are “moving toward”.  When discussing symbiotic relationships between animals (for example, aphids and ants), the participants are said to be co-operating, or (even) acting altruistically(!).  It even seems to be recognized that the individual organisms cannot cooperate, because they lack intelligence, but somehow the species can

The advantage that this kind of misuse of evolution brings to environmentalism is only a minor example of the damage that is done philosophically by casting evolution in this form.  Species survival becomes over-valued.  Loss of “diversity” in the gene pool is a fundamental concern if the genes are the value that is to be preserved in evolution.  And certainly, any human action is at odds with the “natural” progression of evolution.

The larger issue with the collectivist form of evolution theory is that it creates an opportunity for critical attack.  Looking at the progression of traits in a historical population, any apparent sudden change can be questioned – “what caused the genes to ‘do’ this?”, or “what happened to this species – where did it come from; where did it go?”.  In the proper consideration of the theory, these are seen to be questions focussed on invalid concepts; however, in the modern discussion, these are weak points to defend.

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Voyage of the Beagle

(This post was started sometime in October, 2007. I’ve completed it in March, 2008, but altered the timestamp to indicate its approximate date of conception).

I’ve just finished reading Charles Darwin’s first major book, Voyage of the Beagle. This is an account of a 5 year surveying voyage aboard the HMS Beagle, circumnavigating the globe, which Darwin joined as an observer. I had been interested in reading Darwin’s evolutionary work – Origin of Species, Descent of Man – and had acquired a comprehensive volume of four of his books published recently as “From the Simplest of Beginnings”. It is one of my odd characteristics to insist on reading such things from cover to cover, and the first of the works in this collection was the Beagle.

I approached this book figuring it could be a very dry account of a naturalist on an exploring expedition, filled with descriptions of flora and fauna, using terminology with which I would be unfamiliar (not at all having an interest or education in biology), loaded with Latin categorization. I was very wrong in this prejudgement. Although there is plenty of description of flora and fauna, Latin species and genera are used, and familiarity assumed, Darwin focuses this work more on anthropology than biology. There is also a fair bit of geology – in fact, the only original theory stated in this work is on the formation of coral islands and barrier reefs, having to do with the rising and falling of land masses.

Another surprise was in the specific geographical focus on South America. The mission of the Beagle was to survey the coasts ofthis continent, and they spent about 3-1/2 years of the 5 year voyage sailing from point to point along its coasts. I had expected more coverage of areas farther from European influence – Pacific islands, southeast Asia, Africa – but indeed the Beagle visited no location that had not previously been explored, and Darwin’s account dwells upon the colonized areas much more than those predominantly aboriginal. There are no exciting discoveries revealed, no strange new species found (plenty of new species, but not particularly unusual), and little in the way of drama portrayed.

Nonetheless, it is in his descriptions of the people and societies that he encounters that I found the most thought-provoking material. One encounter in particular is worthy of discussion.

The Beagle visited Tierra del Fuego, at the southern tip of South America. The native inhabitants of Tierra del Fuego were the Yamana Indians, living in one of the least hospitable areas on Earth, in a stone age society. This area of South America has a high annual temmperature near 50 degrees (F), and only a handful of days without precipitation. The Yamanas were strictly a hunter/gatherer tribe, attempting no agriculture, and commonly went through periods of starvation, during which they resorted to cannibalism (of the older women in the tribe) to survive. It is to be noted that they remained in the Tierra del Fuego area, for apparently thousands of years, despite being only a few hundred miles south of the much more temperate areas supporting advanced civilization.

On a previous visit to the area, the Beagle had taken four of the natives on board and returned with them to England, where they became well-known “celebrities”, and visited with the King and Queen. The youngest of these captives, whom the British called Jemmy Button, was educated in Britain, and acquired a limited understanding of the English language. During Darwin’s voyage on the Beagle, Jemmy and two other surviving captives were returned to Tierra del Fuego. The Beagle returned to the area after a few months, to find Jemmy reverted completely to his native condition – naked andemaciated. A small party of Europeans remained in the area while the Beagle continued its explorations. Upon the return of the Beagle after a couple more months, it was found that the Yamanas, led by Jemmy, had attacked the small campsite, stealing food and various other items. Twenty years later, a missionary group was similarly attacked and massacred, again by a party of Yamanas lead by Jemmy.

I find this story of interest in several ways. What struck Darwin was the fact that these were human beings of the same species as Europeans, and in his commentary he wonders if and how this can really be the case. What I find fascinating is that this stone age tribe, when exposed to civilizations providing modes of living clearly superior to their own, not only failed to acquire any of the advantages of that interaction, but clearly could not understand the advantages, and actively chose to ignore them. In this, I am not merely referencing the Jemmy Button story, but returning to the observation that Tierra del Fuego is close enough to Patagonia to expect that some Fuegians must have wandered into these regions and returned home to tell of this land of plenty located only a few hundred miles to the north. Recalling that the Yamanas had been in this region for perhaps as long as 10000 years prior to the Beagle’s visit, I find it fascinating that this pocket of stone age humans persisted for so long when the surrounding humans advanced into civilization.

There are other cases of stone age peoples surviving far into the 20th century, but the ones I recall have all been islanders, separated from civilization by thousands of miles of ocean, or Africans, in which the majority of the continent until very recently had been living in pre-historic conditions.

I further wonder about the mentality of the Tierra del Fuegians. Returning to a consideration of the bicameral mind theory of Jaynes (which I may not have discussed in this blog – I apologize, but will refer the reader elsewhere instead of going through this here), I wonder if these latter stone age peoples are not still bicameral. If so, there may be a case for declaring them to be of another species than human, in answer to Darwin’s contemplations.

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The Role of Technology in Human Evolution

There is a rather popular conception that modern technology will result in the end or drastic curtailment of human evolution. With the advent of various medical improvements, those with conditions that would otherwise result in high morbidity prior to adolescence are now much more likely to survive to a reproductive age, and thereby will not be bred out of the gene pool. The result, it is argued, is that we will evolve into an increasingly weakened population, exhibiting a rapid increase in the severity and number of serious genetic conditions.

To counter this argument, we need to recall the unique nature of the human organism. Our primary survival skill is our rational faculty, and its ability to create increasingly advanced understanding of the Universe. This in turn allows the development of a steadily advancing technology. By “technology” is meant a set of tools allowing the modification of our physical world to better suit our needs and desires. While other animals can, in a very limited sense, alter their immediate environment to increase their likelihood of survival through the instinctive actions that they have evolved to exhibit, humans have a much more comprehensive ability to modify their survival environment. The beaver builds a dam to slow the flow of water, allowing the beaver to live in calmer waters. Man builds a hydroelectric power plant to provide electricity to thousands of homes, allowing a city to exist in a sub-freezing climate. Key to the human condition is the ability to pass acquired knowledge from generation to generation, allowing a continually accelerating advancement of knowledge, and commensurate with this rise in understanding, a continually rising level of technology.

Technology allows adaptation of the environment such that the average fitness of the individual in that environment is improved. Acting at a pace relative to which biological evolution is stationary, technology dramatically improves the likelihood of species survival, as it enables rapid adaptive change of the effective environment as the underlying environment changes. As an example, consider the advent of a lethal virus – for concreteness, say the “bird flu” did, as the media scaremongers are suggesting, turn into a human pandemic. When such events occurred in the pre-industrial period (e.g. the bubonic plague), huge segments of population were lost, and it can be envisioned that such an event could lead to rapid extinction, in a time period far too short to allow biological evolution to save the species. In the presence of modern technology, a vaccine can be expected to be developed in a matter of years, resulting in the preservation of a large, perhaps majority, segment of the human species. The effective environment for humans would thereby be modified to neutralize the effect of the bird flu virus.

This observation, however, does not nullify the process of evolution. Rather, it makes humans less dependent on it for survival, specifically with respect to events occuring much faster than evolutionary time scales.

To further illustrate the permanent presence of evolutionary processes, let us consider another (possibly fictional) concrete example. I will conjecture that in the 1800s, the occurence rate of dangerously high blood pressure, caused by genetic defects, in teenagers was much lower than at the present time. My hypothesis is based upon current medical practice, which includes early screening for high blood pressure, and available medication for its treatment. In the 1800s, with these practices not in place, morbidity rates for such a condition prior to reproductive age would have resulted in those genetic conditions being virtually eliminated from the gene pool. Today, the effective environment has changed to neutralize the effects of such a condition, and evolution has been “allowed” to produce an increasing population of individuals with adolescent high blood pressure.

Let us also suppose that at some date in the future, a societal collapse occurs, in which medical technology is no longer available for the treatment of this condition. The effective environment has now changed to put those with high blood pressure at much higher survival risk. In this event, the process of evolution will continue, and will rapidly remove the genetic variation that results in adolescent high blood pressure from the gene pool.

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Thoughts on Evolution : Definition

Our discussion group has occasionally focused on the topic of Evolution, attempting to understand its true nature and recognize both its creative power and limitations. The following summarizes my opinions on both the general topic of evolution, and various specific points we have covered.

The definition of Evolution has itself been a matter of small controversy. Dictionary definitions are somewhat inconsistent. Here are the biological definitions from a few sources:

“The theory that groups of organisms change with passage of time, mainly as a result of natural selection, so that descendants differ morphologically and physiologically from their ancestors” (American Heritage)

“a process of change in a certain direction”, “a theory that the various types of animals and plants have their origin in other preexisting types and that the distinguishable differences are due to modifications in successive generations ” (Meriam-Webster Medical Dictionary)

“a process of continuous change from a lower, simpler, or worse to a higher, more complex, or better state ” (Meriam Webster)

“a process in which something passes by degrees to a different stage (especially a more advanced or mature stage)” (WordNet)

My personal understanding of the concept of (biological) evolution is a process of gradual change through distinct generations of individuals of a defined species in which the average fitness of the individuals improves relative to the species’ environment.

A question which we have repeatedly faced is whether a progression from “simple” to “complex” organisms is an intrinsic aspect of evolution. Notably, the definitions given above vary between including or ignoring this further refinement of the term evolution.

Harry Bingswanger, in a lecture given expounding his thesis “The Biological Basis of Teleological Concepts”, defined evolution as a progression from simplicity to complexity, and marked evolution as the process by which goal-directed actions (perhaps more descriptively termed “behaviors”) are created in species (as well as physical, structural properties of species). I (respectfully) disagree with including the progression from “simple” to “complex” as an essential element of the concept of evolution.

First, let me provide a thought experiment as a counter-example. Let’s assume that Mars once had an environment conducive to the development of complex living organisms – liquid water was present, the atmosphere was denser, and temperatures above freezing were common – and that complex life forms were abundant. Then, as the planet “aged”, the environment gradually changed toward today’s condition (arid, little or no water and oxygen, continual sub-freezing temperatures). Under these increasingly hostile conditions, it is rather easy to conceive that simpler life forms had a fitness advantage over more complex forms, and that evolution resulted in a reduction in complexity, perhaps ending in microbes [which I can conjecture may yet exist on that planet] as being the dominant life form. A fair response to this “counter-example” is that it is non-existent (to our knowledge), and that the one and only example of the actions of evolution on a global living system exhibits a progression from simple to complex organisms.

My concept of evolution, however, is based upon more than biological evolution. With some considerable experience in the use of evolutionary algorithms to perform optimizations, I have abstracted my concept of evolution to encompass both the mathematical formulations of evolution, as used in optimizations and various simulations of “artificial life”, as well as biological evolution. The variations upon the mathematical formulations of evolution are extremely numerous, while the underlying processes of biological evolution at the DNA level may be as numerous. The definition I suggested earlier for evolution fits my understanding of both the biological and mathematical forms of the process (to my current knowledge, of course).

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