Chapter XII - Geographical Distribution
Darwin noted that the fauna and flora of the different continents at approximately the same latitudes were often different. Furthermore, species groups isolated on their respective continents were often more similar when compared with species on other continents. He insisted that the same observations held true for marine environments somewhat isolated from each other. The fauna on the east shores of South America, for example, were often more closely related to each other than those on the west shores of the same continent. From these observations, he concluded:
The dissimilarity of the inhabitants of different regions may be attributed to modification through variation and natural selection, and probably in a subordinate degree to the definite influence of different physical conditions (Pages 348-349).
In the gradual evolution of species, isolation was important:
Thus the high importance of barriers comes into play by checking migration; as does time for the slow process of modification through natural selection" (page 349).
However, new species do not develop simply because they are isolated; they only evolve through their competitive interactions with other species:
If a number of species, after having long competed with each other in their old home, were to migrate in a body into a new and afterwards isolated country, they would be little liable to modification; for neither migration nor isolation in themselves effect anything (Page 349).
Critique
Darwin's observation that species groups on isolated continents were more closely related than they were to species groups on other continents provided support for common descent. Few would argue, for example, that five parent species of cichlid fishes gave rise to 300+ new species of cichlids during the last 12,400 years in Lake Victoria, Africa. Nor would anyone argue the point that Canis lupus, the wolf, was the parent of numerous varieties of dogs, C. familiaris, nor that the Alaskan brown bear (Ursus middendorffi) gave rise to the polar bear (Thalarctos maritimus) in a period of 10,000 years, nor that insects and other arthropods, starfish and sea urchins and other echinoderms, and chordates appeared in quantum leaps during the Cambrian Period, nor that bats, rodents, carnivores, whales, horses, and cattle appeared abruptly at the end of the Paleocene and early Eocene Epochs. How did random mutation at an average rate of 10-9 to 10-10 per base pair replication (Denton, 1986, 267) give rise to so many favored and complex variations over relatively short periods of time? The problem from the Darwinian view point, was not that ancestor species gave rise to new sister species but that new species and even new phyla and orders of species appeared quickly to fill niches throughout the world. Because the Darwinian model failed to explain these events, I would like to offer an alternate hypothesis I will designate as "epigenetic niche-match". The basis for my hypothesis follows.
I suggest the possibility that the process of rapid genetic change already exists about and within us. A parallel process that could explain rapid but directed genetic changes takes place regularly within our own immune systems. Our immune systems can produce billions of different-shaped antibodies to confront invaders. When the system finds an antibody that fits the invading microbe, the antibody sticks to and targets the invader so a white cell can approach it and make the kill. Incredibly, the immune system creates new antibodies to fit new invaders and then over the course of time, alters its own DNA in a highly organized manner to improve the fit of the antibody.
The immune system changes its own DNA in several ways. The system can take a gene's RNA and 'cherry pick' for the needed information or even splice the DNA itself to create antibodies with new shapes. Thirdly, through a process called "somatic hyper mutation," the cell "intentionally" allows a very high level of mutation in just the variable regions of the heavy- and light-chain genes (Behe, 1998: 129).
Ergo, if the immune system can alter DNA to fit internal environmental threats, why could not the physiological systems of species alter DNA to fit environmental opportunities in the form of new niches? One might say: "God abhors a vacuum." This idea is non-Darwinian and reeks of vitalism and preplanning/programming, but we now see a comparable process operating at the level of our own immune systems. But what biochemical mechanisms could account for complex and rapid adjustments to new environmental opportunities?
New research has shown that DNA can change in response to environmental factors and that those changes may pass to the offspring:
The vast areas of DNA that do not code for proteins, once dismissed as "junk," are now known to conceal important regulatory regions. Some DNA stretches produce small bits of RNA that can interfere with gene expression. And, chemical "tags" on DNA that do not change its sequence - that are thus "epigenetic" - can also influence gene expression and can be modified by environmental factors over the course of a lifetime. This environmentally modified DNA may even be passed on to offspring (Hall 2010:167).
In addition, sequences of DNA called "jumping genes" or "retrotransposons" migrate within the genome of the cell and attach in locations where they may activate genes and influence the functioning of individual cells. Retrotransposons, which comprise up to half of the DNA building blocks (nucleotides) in the genome, can create variability in brain cells and may thereby facilitate rapid adaptations to new environmental conditions (Gage and Moutri 2012).
Furthermore, Meyer (2009: 457, 465) noted that a mark of intelligent design is the conception of outcomes before they exist:
Those outcomes are then actualized by arranging the many disparate parts of the system without the need to develop and maintain functional "intermediate forms" or structures along the way to the desired functional end point...In the cell, protein-coding regions of the genome provide formatting, bracketing, and indexing codes that enable the cell to locate and express specific modules of stored genetic information, the expression of which may be needed to respond to specific environmental stresses or changing developmental conditions.
These observations at the biochemical level may account for rapid speciation and the mechanics of epigenetic matching to changing or new environments.
As noted above, epigenetic matching to environmental niches is apparent in the rapid speciation of cichlid fishes in Lake Victoria, Africa. Darwinian gradualism cannot account for the explosion of cichlid species that developed rapidly in the same body of water without physical isolation. The abrupt appearance of species without isolation also leaves little room for "allopathic speciation" as proposed by Eldredge and Gould (1972). I suggest that only "programming" could account for 300+ new body plans for new species that appeared in such a short period of time. The evolution process was apparently explosive, epigenetic, and preconceived to fill new environmental niches with numerous sister species.
Of course, programmed evolution illustrates definitive limits:
It is now well established that the pattern of diversity at the molecular level conforms to a highly ordered hierarchic system. Each class at a molecular level is unique, isolated and unlinked by intermediates. Thus molecules, like fossils have failed to provide the elusive intermediates so long sought by evolutionary biology. Again, the only relationships identified by this new technique (protein sequencing) are sisterly. At a molecular level, no organism is "ancestral" or "primitive" or "advanced" compared with its relatives (Denton, 1986:290).
Furthermore, Meyer (2013: 411) noted that natural selection acting on random mutation, the hallmark mechanism of neo-Darwinism, cannot account for the production new genetic information because:
(1) it has no means of efficiently searching combinatorial sequence space for functional genes and proteins and, consequently,
(2) it requires unrealistically long waiting times to generate even a single new gene or protein. It has also shown that the mechanism cannot produce new body plans because;
(3) early acting mutations, the only kind capable of generating large-scale changes, are also invariably deleterious, and
(4) genetic mutations cannot
, in any case, generate the epigenetic information necessary to build a body plan.
Having offered a reasonable hypothesis to explain the rapid appearance of sister species, I am well aware that epigenetic niche-match cannot account for the explosion of whole new body plans; e.g., the sudden appearance of disparate phyla in the Cambrian.
Several years after I formulated my hypothesis epigenetic niche-match to account for rapid speciation, I read about geneticist James Shapiro's proposal "natural genetic engineering" (Meyer 2013:332-335). Shapiro, now at the University of Chicago, observed that at the cellular level, organisms within a population frequently modify themselves to adjust to environmental stimuli. Under environmental stressors, organisms induce mutations in a directed manner to help ensure their survivability. They respond in a "cognitive" and directed manner in total opposition to random genetic changes fundamental to the neo-Darwinist model for evolution. Shapiro's view of evolutionary process favors preprogrammed adaptive capacity or "engineered" change. It occurred to me that Shapiro's conclusions, based on a wide range of data/observations, paralleled my own views on a process of rapid speciation, which I fondly labeled epigenetic niche-match.
Insofar as Shapiro's views of evolutionary process are concerned, what is the meaning of natural in his "natural genetic engineering" in contrast to "cognitive" or "directed manner" and "preprogrammed adaptive capacity?" What is the source of all that precise engineering void of random mutation and natural selection, the hallmarks of neo-Darwinism? Perhaps it's epi-natural though common, still spooky! For all of our experience links inexplicable, obvious engineering to an engineer.
Single Centres of Supposed Creation
Darwin observed that some creationists believed that God created individual species or species groups where they now exist. To counter this belief, Darwin said that modification by descent and migration explained the distribution of organisms. He noted that the relatedness of species and species groups was closer in regional areas than it was across isolated continents. Also, species on islands frequently showed close affinities to species on the nearest mainland.
However, species located on continents or other large land masses were:
...kept nearly uniform by intercrossing; so that many individuals will go on simultaneously changing, and the whole amount of modification at each state will not be due to descent from a single parent (Page 353).
Thus, God did not create a single pair of organisms to perpetuate their "kind" but the species as a whole evolved to produce a new species through natural selection acting on random variation. Secondly, species migrated to all available, favorable habitats.
Critique
It would seem odd for anyone to argue that species did not cross land bridges between continents or fly or float to islands of available, favorable habitats. The Bible recorded that God told Noah:
Bring out with you every living thing that is with you of all fish - birds and animals and every creeping thing that creeps on the earth - so that they may abound on the earth and be fruitful and multiply on the earth...And every animal, every creeping thing, and every bird, everything that moves on the earth, went out of the ark by families (Genesis 8:17-19).
The biblical account indicated that various "kinds" (classification at or above the genus level) of animals migrated away from one location by "families" or related groups to occupy habitats across the planet. They had to migrate from their point of release to accomplish the biblical mandate to "abound on the earth and be fruitful and multiply..."
Darwin ended this section with his classic model for gradual macroevolution. He stated that on large land masses, species would approach stasis through interbreeding but the population as a whole would change ever so slowly through innumerable intermediate steps into a new species. Again, the fossil record did not and does not support this gradualist model, which represents Darwin's core hypothesis for the origin of species.
Means of Dispersal
In this section, Darwin discussed the dispersal of species. Sea levels rose and fell and thereby controlled the dispersal of species but the locations of continents remained fairly stable. Geologists reported:
...abundant evidence of great oscillations in the level of the land or sea; but not of such vast change in the position and extension of our continents... (Page 354).
During different geologic ages, species could disperse across land bridges to other continents or to islands to populate them. Likewise, populations of marine organisms would reunite when increased ocean levels flooded across land bridges. Seeds of many plants flushed by rivers into ocean currents might float for a thousand miles or more and still be viable. Migrating birds might carry seed in bits of dried mud on their feet and beaks to distant destinations. Migrating locusts could cross hundreds of miles and deposit grass seed they had ingested. The root structures of trees washed into the ocean could transport rock and seed-bearing soil for miles across salt water.
Darwin placed various plant seeds and fruits into sea water for varying amounts of time to test their germination and floatation rates. He thereby showed that the dispersal of numerous species of plants common to Great Britain could disperse by sea water to locations hundreds of miles distant.
Critique
It is common knowledge that many species use apparently ingenuous ways to disperse widely. This observation appears to have no particular relevance to Darwin's general theory of macroevolution. In addition, the biblical account of creation required the various kinds of animals to "abound on the earth;" that is, to disperse to favorable habitats across the planet.
Dispersal during the Glacial Period+
The upper elevations of mountains in America and Europe support species of animals and plants that are closely related to species from more northern latitudes. During glacial events, these species spread south across low lands in America and Europe. When the climate warmed again, those species that required colder climates retreated to higher elevations in the mountains, which explained the current spotty and isolated distributions of those species.
In like fashion, when ocean levels rose with the advance of warmer conditions, marine species on both the west and east shores of the American continents had greater opportunity to migrate between oceans. These migrations explained the similarities among groups of species in both locations.
Darwin provided these observations and explanations to counter beliefs by persons such as Gmelin who in 1747 erroneously concluded "that the same species must have been independently created at many distinct points..." (Page 360). Darwin said:
We cannot maintain that such species have been created alike, in correspondence with the nearly similar physical conditions of the areas; for if we compare, for instance, certain parts of South America with parts of South Africa or Australia, we see countries closely similar in all their physical conditions, with their inhabitants utterly dissimilar. (Page 365).
Critique
The proximate effects of climate change on the distribution of species is of considerable interest but has no particular bearing on questions of ultimate causes.
Darwin observed that species assemblages are different on different continents along the same latitudes under similar climatic conditions. This observation lead Darwin to conclude that those assemblages evolved naturally where they were found. God had nothing to do with the appearance nor distribution of species. In other words, disparate species that filled similar niches on different continents showed that natural selection was responsible for the production of anomalous, unrelated species. And, the presence of related species on different continents proved that those species had dispersed widely from the common location of their evolutionary origin.
If Darwin could come up with a possible explanation or hypothesis that might explain the general mechanics of some process, he assumed it had far-reaching explanatory power and proved that God was not involved in the process of speciation. For example, if oaks grow from acorns; God did not create oaks nor acorns becau
se acorns, not God, had produced the oaks. His reasoning at the biological level was simplistic; his leaps to ultimate causes, speciously and purposefully exclusive. Surely he was aware of the biblical mandate in Genesis 8 for wildlife species to "abound on the earth;" that is, "reproduce and disperse across the earth."
Alternate Glacial Periods in the North and South
In this section Darwin again discussed evidence for recurring glacial periods around the planet in both the northern and southern hemispheres. He cited numerous examples of closely related species of plants and animals found under similar climatic conditions but widely distributed around the world. With the advent of colder climate, artic and temperate species moved to formerly warmer locations. With global warming, those species groups moved to new areas that provided more temperate or alpine habitats. In like fashion, tropical species moved into higher elevations afforded by mountains or expanded to different latitudes with the warming of climate. These migrations explained the present wide but often localized distributions of artic, temperate, and tropical species across the planet.
Critique
General explanations for plant and animal distributions around the planet have not changed much since Darwin's time. The distribution of organisms on the planet does not conflict with the biblical mandate for organisms to fill their designated niches on Earth.