Creation Matters Jul/Aug 1996, Vol.1, No.4

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Let's Rewrite the Book on the Galapagos Islands

by Margaret J. Helder, Ph.D.

Just about everyone who has studied biology associates "Galapagos" with "finches," and both with Charles Darwin. It was Darwin's speculations on the origin of new species-and by extrapolation on the supposed process of evolution, which really put the obscure Galapagos islands "on the map." Many years have passed since Darwin published his book. There has been ample time for critical reviews of the ideas of "adaptive radiation" and new species formation. Unfortunately all too few people, be they creationist or evolutionist, have contrasted Darwin's conclusions with the facts about Galapagos.

Setting the stage

Huddled together in the Pacific, about 960 kilometers west of South America, the Galapagos Archipelago consists of 29 major islands as well as numerous tinier pieces of real estate. A table in Science (Johnson and Raven, 1973, pp. 893-895) provides statistics about the islands including area, elevation, distance from nearest island, and distance from Santa Cruz (the central island). Most islands are small and situated close to other islands. Only one (Isabela) boasts an area larger than 1000 square kilometers.

Thirteen species of finches (in two genera) live on these islands. Up to ten species live together on one island, and no island (except the merest rocky outcrops) has only one species. Often several species share one habitat. Food preferences overlap somewhat too (Lack, 1953, pp. 66-71). Since even today, individuals of these species routinely come into contact, there would have been plenty of opportunity for back crosses before the species were reproductively distinct (if divergence had been attempted while sharing a given habitat). Because of this problem, generations of science students have been taught that island archipelagos are the favoured site for evolutionary divergence or adaptive radiation. Individual populations, in physical isolation on different islands, are presumed to have developed into new species, and only after they were reproductively distinct did they reinvade each others' territory.

How often do birds fly from one island to another? This information would help assess how separate the populations on the islands really are. Could they realistically be expected to stay isolated long enough to become distinct species? Johnson and Raven (1973, p. 895) suggest that the plants of the moist uplands on Galapagos have, within the past 10,000 years, been carried to the islands. The finches in this habitat eat mainly insects, but if other birds were flying over from the mainland during the last several thousand years, why not the finches as well?

Peter and Rosemary Grant, in their recent studies on the Galapagos finches, are widely credited with having documented evolution at work. "Evolution by natural selection has been caught in flagrante delicto and at last scientifically tested in the raw." (The Economist, 1994, p. 80) The Grants studied the medium ground finch (Geospiza fortis) on Daphne Major, an island of less than 50 hectares, and also home to the cactus finch G. scandens. The Grants found that the ground finches which survived drought, tended to be those with relatively larger beaks since only plants with larger seeds were available at this time. The environment was an oscillating one, however. There were wet years too. "Effects of the droughts of 1977 and 1982 were approximately offset by selection in the opposite direction-toward smaller body size-in 1984- 85" (p. 86). The Grants speculated that 20 droughts (with no selection in the other direction in between) would be enough to produce a new species of finch. Such an environment without oscillations just doesn't happen. Let's get realistic.

Studies on Small Populations

Isolated populations such as we find on islands, are popularly believed to provide the needed raw material for evolution. One suggestion is that small populations may allow for genetic drift and founder effect, chance events which could enable populations to avoid some of the high mortality which results from the cost of selection (Grant and Falke, 1974, pp. 1670-1671). The idea is that small populations can get a head start on divergence from the main body of the species, and if there are many small populations, then many trials are possible. One success is good enough. The catch, however, is that the process does not work that way. As Verne Grant remarks (1977, p. 129), small populations quickly lose any variability they had so that they lack any potential for change. What these populations are prone to do is become extinct.

Recent studies on island ecology have reinforced the view that small populations are extinction prone. According to a 1967 monograph entitled The Theory of Island Biogeography (MacArthur and Wilson), new species seemed to spread from large continental land masses out to remote islands such as Fiji. There the new species supplanted the older ones which had previously arrived. According to these theorists, island fauna are the result of immigration and extinction. Speciation could be disregarded as a factor (Quammen, 1996, p. 72). These two men also discovered that smaller territories supported many fewer species.

Concerns raised by MacArthur and Wilson have been confirmed. John Terborgh (1974, pp. 715-722) studied islands which, only thousands of years ago, were presumed to have supported a fauna like the nearby mainland. He concluded that there had been "nontraumatic population declines compelled by unrelenting forces that are yet to be identified." (p. 718) His recommendation was that only large natural reserves, at least one thousand square km in area, will be adequate to prevent a further veritable rush of extinction. Terborgh's conclusions have been reinforced by studies on islands formed when flooding of the Panama Canal isolated tracts of tropical forest. Both for birds (which Terborgh discussed), and for trees, the pattern of declines was the same. With trees, the decline in diversity was 30-40 times greater than predicted on the basis of chance alone (Putz, Leigh,. and Wright, 1990, pp. 18-23). Such astounding declines would leave no opportunity for increases in diversity through speciation.

The realization that small populations do not work for evolution and that they often lead to localextinctions, has resulted in new initiatives to protect biodiversity in North America. An article in Science (Mann and Plummer,1993, pp. 1868-1871) describes proposals to devote huge tracts ofterritory (up to one half the continent) to natural communities. E. O. Wilson is an enthusiasticsupporter of the concept which would see people squeezed into small pieces of territory.

The standard view then, first promoted by Mayr in 1947, was that apart from polyploidy, geographic isolation was essential for speciation in animals. Lack also maintained that most species develop in physical isolation. He further claimed that archipelagos like Galapagos, provided the evidence for such adaptive radiation. Peter Grant supports these views (1991, p. 83). But if small populations are unpromising for speciation, how about large populations? According to Verne Grant (1977, p. 129), new mutations have no hope of spreading in large populations because they would be swamped by wide outcrossing. Alternatively, an elaborate model for sympatric speciation was proposed by Stuart Pimm (1979, pp. 131-139). The process of two species in the same area diverging from one another, would depend upon some very special events: repeated mutations of the same allele; initial selection of the heterozygote; and lastly superior fitness of both homozygotes and preferential mating with the like homozygote. This is like homozygous blue eyed people marrying only similar individuals, and brown eyed people marrying only their own kind, while refusing to marry heterozygous brown eyed individuals. Before marrying, one would have to review the family tree! In short, the whole thing is a most unlikely scenario.

Natural selection, as a mechanism of speciation, is clearly in trouble. Punctuationists like Steven J. Gould are frank about this, " even if local populations alter as the [neo-Darwinian] synthesis maintains, we now doubt that the same style of change controls events at the two major higher levels: speciation and patterns of macrevolution." (1980, p. 121) While punctuationists seek a new mechanism for evolution, traditional Darwinists extrapolate natural selection all the way to the higher levels of organization. Even many creationists extrapolate the process to the genus level or above. These creationists, through their support of rapid diversification of kinds following the flood, find themselves in bed (metaphorically speaking), with traditional Darwinists. Perhaps the time has come to critically reevaluate that position.

References

Anon. 1994. Darwinian Evolution: Birds Eye View. The Economist 332(7876):80.

Gould, Stephen Jay. 1980. Is a New and General Theory of Evolution Emerging? Paleobiology 6(1):119-130.

Grant, Peter R. 1991. Natural Selection and Darwin's Finches. Scientific American 265(4):82-87.

Grant, Verne. 1977. Population Structure in Relation to Macroevolution. Biologisches Zentralblatt 96:129-139.

Grant, Verne and Robert H. Falke. 1974. Population Structure in Relation to Cost of Selection. Proc. Nat. Acad. Sci. USA 71(5): 1670-1671.

Johnson, Michael P. and Peter H. Raven. 1973. Species Number and Endemism: The Galapagos Archipelago Revisited. Science 179(March 2):893-895.

Lack, David. 1953. Darwin's Finches. Scientific American 188 (4):66-71.

Mann, Charles C. and Mark L. Plummer. 1993. The High Cost of Biodiversity. Science 260 (June 25):1868-1871.

Pimm, Stuart L. 1979. Sympatric Speciation: a Simulation Model. Biological Journal of the Linnean Society 11:131-139.

Putz, Frank E., Egbert G. Leigh Jr. and S. Joseph Wright. 1990. Solitary Confinement in Panama. Garden 14(2):18-23.

Quammen, David. 1996. Life in Equilibrium. Discover 17(3):66-77.

Terborgh, John. 1974. Preservation of Natural Diversity: The Problem of Extinction Prone Species. BioScience 24(12):715-722.

FOURTH INTERNATIONAL CONFERENCE ON CREATIONISM -- CALL FOR PAPERS

High quality papers for the Fourth International Conference on Creationism (ICC), Summer 1998, Pittsburgh, PA, are now invited for submission. In continuation of the Third ICC, the theme of the Fourth ICC is Developing and Systematizing the Creation Model of Origins, making the Fourth ICC a "working" conference.

The interested author should write a 500 word abstract of his/her paper, categorize it according to the area classification below, and submit a copy no later than 30 December 1996 to each of the following at their addresses provided below: appropriate Area Liaison, Technical Review Committee (TRC) Chairman, and ICC Proceedings Editor. Early submission is highly recommended.

Each submitted abstract will be evaluated by the liaison, in consultation with the Technical Review Committee (TRC), for possible inclusion into the review process. If accepted, the author would be sent a packet detailing format of ICC papers, and the author would submit his/her paper to the editor assigned by the liaison no later than 29 June 1997. The editor will send each paper to referees, work with the author to improve his/her paper, and have final jurisdiction over the acceptance or rejection of each such paper. Final drafts of all papers, including any revisions, are to be in the editor's hands no later than 27 February 1998.

Papers dealing with the age of the earth/universe must be either from a young-earth perspective or offer a positive/constructive criticism of that perspective. Papers from an old-earth/old-universe perspective will not be considered.

The Conference theme is partitioned into major areas overseen by TRC liaisons, and each area is further divided into sub-areas overseen by one or more editors.

LIAISON ADDRESSES

Stephen Rodabaugh, 242 Bradford Dr., Canfield, OH 44406-1001 USA
Robert Harsh, 439 Little Creek Rd., Harmony, PA 16037 USA
Robert Walsh, 9312 Old Perry Hwy., Pittsburgh, PA 15237-4951 USA
Ralph McKelvy, 142 Sechan Drive, Portersville, PA 16051 USA
Lionel Dahmer, 440 College Park Drive, Monroeville, PA 15146 USA
TRC CHAIRMAN Steve Rodabaugh (See above)
ICC PROCEEDINGS EDITOR Robert Walsh (See above)

AREA CLASSIFICATION

I. FOUNDATIONS OF SCIENCE
Liaison: Stephen Rodabaugh
Area Editors:
(1) Biblical Models and Hermeneutics: D. Rodabaugh
(2) Mathematical and Logical Models: S. Rodabaugh
(3) Philosophy of Science: J.M. Reynolds

II. LIFE SCIENCES
Liaison: Robert Harsh
Area Editors:
(1) Cell and Molecular Biology: W. Frair
(2) Organismal Biology: W. Frair, P. Nelson
(3) Biogeography: K. Wise
(4) Systematics: W. Frair, P. Nelson
(5) Genetics: W. Frair
(6) Ecology: K. Cummings

III. ASTRO-SCIENCES
Liaison: Robert Walsh
Area Editors:
(1) Astro-chronometry: D. DeYoung
(2) Cosmogony & Cosmology: D. DeYoung, R. Humphreys
(3) Atmospheric Sciences: L. Vardiman

IV. SOCIAL SCIENCES AND THE HUMANITIES
Liaison: Ralph McKelvey
Area Editors:
(1) Philosophy of History: P. Ackerman
(2) Linguistics: P. Ackerman
(3) Archeology: P. Ackerman
(4) Psychology: P. Ackerman
(5) Economics and Political Science: J. Eidsmoe
(6) Education: J. Eidsmoe

V. EARTH AND PLANETARY SCIENCES
Liaison: Lionel Dahmer
Area Editors:
(1) Geo-chemistry: A. Snelling
(2) Geo-physics: R. Humphreys
(3) Physical Geology: S. Austin
(4) Sedimentary Geology: S. Austin
(5) Paleontology: K. Wise

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Creation Calendar

The events below are for information only; the listing of an event does not necessarily imply endorsementby the Creation Research Society.

August 4 - 10
Bob Marshall Wilderness Expedition
Creation Research Society
Dr. John Meyer, 520-636-1153

August 5-9
Creation Training for Educators
Institute for Creation Research, San Diego, CA
Debbie Brooks, 619-448-0900, ext. 249

August 11 - 16
Creation Vacation: Redcloud Family Mountain Adventure I
Alpha-Omega Inst., Grand Junction, CO
Dave or Mary Jo Nutting, 303-245-5906

August 18 - 23
Creation Vacation: Redcloud Family Mountain Adventure II
Alpha-Omega Inst., Grand Junction, CO
Dave or Mary Jo Nutting, 303-245-5906

August 24
Teaching Creation in Public Junior College
Rick Balogh, geology professor
South Bay Creation Science Assoc.
Los Angeles Area
Phyllis, 310-328-2845

August 26-30
Summer Institute on Scientific Creationism
Summit Ministries, Manitou Springs, CO
Amanda Bowers, 719-685-9103

September 28
Petrified Forests and Related Issues
Dave Phillips, M.S. Paleoanthropology
South Bay Creation Science Assoc.
Los Angeles Area
Phyllis, 310-328-2845

November 23
Teachers' Workshop on Creation Science
Registration required
Creation Education Resources
P.O. Box 1853, Orange Park, FL 32097-1853
William Overn, 904-269-9007 (voice/fax)

Creation Matters
A publication of the Creation Research Society
Volume 1, Number 4
July/August 1996

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Let's Rewrite the Book on the Galapagos Islands

FOURTH INTERNATIONAL CONFERENCE ON CREATIONISM -- CALL FOR PAPERS

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