Problem 5: Abrupt Appearance of Species in the Fossil Record Does Not Support Darwinian Evolution
Editor's note: This is Part 5 of a 10-part series based upon Casey Luskin's chapter, "The Top Ten Scientific Problems with Biological and Chemical Evolution," in the volume More than Myth, edited by Paul Brown and Robert Stackpole (Chartwell Press, 2014). The full chapter can be found online here. Other individual installments can be found here: Problem 1, Problem 2, Problem 3, Problem 4, Problem 6, Problem 7, Problem 8, Problem 9, Problem 10.
The fossil record has long been recognized as a problem for evolutionary theory. In the Origin of Species, Darwin explained that his theory led him to believe that "[t]he number of intermediate varieties, which have formerly existed on the earth, [must] be truly enormous."65 However, he understood that the fossil record did not document these "intermediate" forms of life, asking, "Why then is not every geological formation and every stratum full of such intermediate links?"66 Darwin's answer showed the tenuous nature of the evidence backing his ideas: "Geology assuredly does not reveal any such finely graduated organic chain; and this, perhaps, is the most obvious and gravest objection which can be urged against my theory."67
Today, some 150 years later, out of thousands of species known from the fossil record, only a small fraction are claimed to be candidates for Darwin's intermediate forms. Fossil evidence of evolutionary intermediates is generally lacking, as the late evolutionary paleontologist Stephen Jay Gould admitted: "The absence of fossil evidence for intermediary stages between major transitions in organic design, indeed our inability, even in our imagination, to construct functional intermediates in many cases, has been a persistent and nagging problem for gradualistic accounts of evolution."68
Darwin attempted to save his theory of gradual evolution by maintaining that intermediate fossils are not found because of "the extreme imperfection of the geological record."69 Even Gould noted that Darwin's argument that the fossil record is imperfect "persists as the favored escape of most paleontologists from the embarrassment of a record that seems to show so little of evolution directly."70 But in the last few decades, this excuse has lost credibility.
Paleontologists today generally recognize that while the fossil record is imperfect, it is still adequate to assess questions about evolution. One study in Nature reported that "if scaled to the ... taxonomic level of the family, the past 540 million years of the fossil record provide uniformly good documentation of the life of the past."71 Another paper in Paleobiology evaluated our knowledge of the fossil record and concluded that "our view of the history of biological diversity is mature."72 Paleontologists now increasingly recognize that "jumps" between species, without intermediates, are not simply the result of an incomplete record. Niles Eldredge, an evolutionary paleontologist and curator at the American Museum of Natural History, puts it this way with Ian Tattersal: "The record jumps, and all the evidence shows that the record is real: the gaps we see reflect real events in life's history -- not the artifact of a poor fossil record."73 This conclusion did not come easily, as one scientist who studied under Gould felt the need to implore his colleagues that "[e]volutionary biologists can no longer ignore the fossil record on the ground that it is imperfect."74
A Pattern of Explosions
The eventual realization that the fossil record is not entirely incomplete has forced evolutionary biologists to accept that the record shows a pattern of explosions, not gradual evolution of living organisms. One biology textbook explains:
Many species remain virtually unchanged for millions of years, then suddenly disappear to be replaced by a quite different, but related, form. Moreover, most major groups of animals appear abruptly in the fossil record, fully formed, and with no fossils yet discovered that form a transition from their parent group.75
Probably the most famous instance of abrupt appearance is the Cambrian explosion, in which nearly all of the major living animal phyla appear for the first time. An invertebrate biology textbook explains:
Most of the animal groups that are represented in the fossil record first appear, "fully formed" and identifiable as to their phylum, in the Cambrian, some 550 million years ago. These include such anatomically complex and distinctive types as trilobites, echinoderms, brachiopods, molluscs, and chordates. ... The fossil record is therefore of no help with respect to the origin and early diversification of the various animal phyla...76
Evolutionary scientists acknowledge that they cannot explain this rapid appearance of diverse animal body plans by classical Darwinian processes, or other known material mechanisms. Robert Carroll, a paleontologist at McGill University, argues in Trends in Ecology and Evolution that "The extreme speed of anatomical change and adaptive radiation during this brief time period requires explanations that go beyond those proposed for the evolution of species within the modern biota."77 Another paper likewise maintains that "microevolution does not provide a satisfactory explanation for the extraordinary burst of novelty during the Cambrian Explosion" and concludes "the major evolutionary transitions in animal evolution still remain to be causally explained."78 Likewise a 2009 paper in BioEssays concedes that "elucidating the materialistic basis of the Cambrian explosion has become more elusive, not less, the more we know about the event itself."79
But the Cambrian explosion is by no means the only explosion of life recorded in the fossil record. Regarding the origin of major fish groups, former Columbia University geoscientist Arthur Strahler writes that, "This is one count in the creationists' charge that can only evoke in unison from paleontologists a plea of nolo contendere [no contest]."80 A paper in Annual Review of Ecology and Systematics explains that the origin of land plants "is the terrestrial equivalent of the much-debated Cambrian 'explosion' of marine faunas."81 Regarding the origin of angiosperms (flowering plants), paleontologists have discovered a "big bloom" type of explosion event. As one paper states:
In spite of much research and analyses of different sources of data (e.g., fossil record and phylogenetic analyses using molecular and morphological characters), the origin of the angiosperms remains unclear. Angiosperms appear rather suddenly in the fossil record... with no obvious ancestors for a period of 80-90 million years before their appearance.82
In a similar way, many orders of mammals appear in an explosive manner. Niles Eldredge explains that "there are all sorts of gaps: absence of gradationally intermediate 'transitional' forms between species, but also between larger groups -- between, say, families of carnivores, or the orders of mammals."83 There is also a bird explosion, with major bird groups appearing in a short time period.84 One paper in Trends in Ecology and Evolution titled "Evolutionary Explosions and the Phylogenetic Fuse" explains:
A literal reading of the fossil record indicates that the early Cambrian (c. 545 million years ago) and early Tertiary (c. 65 million years ago) were characterized by enormously accelerated periods of morphological evolution marking the appearance of the animal phyla, and modern bird and placental mammal orders, respectively.85
Of course there are a handful of examples where evolutionary scientists believe they have found transitional fossils documenting gradual Darwinian evolution. The origin of whales has been called a "poster child for macroevolution,"86 where it is believed that around 55 million years ago, certain land mammals lost their hind-limbs and evolved into fully aquatic whales. In particular, it is claimed there are fossil land-mammals with ear-bones similar to whales, and fossil whale-like mammals that retain their hindlimbs.
Even though vertebrate and whale expert Phillip Gingerich admits that we only have "fossils illustrating three or four steps that bridge the precursor of whales to today's mammals,"87 let's assume for a moment that a full sequence of fossils exists. Is this enough to demonstrate that this transition occurred? Even if there are fossils that look like potential intermediate forms, if the overall evolutionary story does not make sense, then the fossils cannot be transitional. In this case, the Darwinian evolution of whales from land-mammals faces serious mathematical challenges from population genetics.
Many changes would have been necessary to convert a land-mammal into a whale, including:
- Emergence of a blowhole, with musculature and nerve control
- Modification of the eye for permanent underwater vision
- Ability to drink sea water
- Forelimbs transformed into flippers
- Modification of skeletal structure
- Ability to nurse young underwater
- Origin of tail flukes and musculature
- Blubber for temperature insulation88
Many of these necessary adaptations would require multiple coordinated changes. But as we saw in Problem 3, such simultaneous mutations require extremely long periods of time to arise via the Darwinian mechanism. Whale evolution now runs into a severe problem. The fossil record requires that the evolution of whales from small land mammals would have to have taken place in less than 10 million years.89 That may sound like a long time, but it actually falls dramatically short, especially given that whales have small population sizes and long generation times.90 Biologist Richard Sternberg has examined the requirements of this transition mathematically and puts it this way: "Too many genetic re-wirings, too little time."91
Whale origins thus provides an interesting case study of evolutionary transitions: On a rare occasion where there actually are fossils that potentially show intermediate traits, unguided neo-Darwinian evolution is invalidated by the short amount of time allowed by the fossil record. If this "poster child" of macroevolution doesn't hold up to scrutiny, what does this tell us about other cases where evolutionists tout supposed transitional fossils?
Human Origins and the Fossil Record
Indeed, the public is commonly told that there are fossils documenting the evolution of humans from ape-like precursors, but a closer look at the technical literature tells a different story. Hominid fossils generally fall into one of two groups: ape-like species and human-like species, with a large, unbridged gap between them. In 2004, the famed evolutionary biologist Ernst Mayr recognized the abrupt appearance of humans:
The earliest fossils of Homo, Homo rudolfensis and Homo erectus, are separated from Australopithecus by a large, unbridged gap. How can we explain this seeming saltation? Not having any fossils that can serve as missing links, we have to fall back on the time-honored method of historical science, the construction of a historical narrative.92
In light of such evidence, a paper in the Journal of Molecular Biology and Evolution called the appearance of Homo sapiens "a genetic revolution" where "no australopithecine species is obviously transitional."93 The lack of fossil evidence for this hypothesized transition is confirmed by Harvard paleoanthropologists Daniel E. Lieberman, David R. Pilbeam, and Richard W. Wrangham:
Of the various transitions that occurred during human evolution, the transition from Australopithecus to Homo was undoubtedly one of the most critical in its magnitude and consequences. As with many key evolutionary events, there is both good and bad news. First, the bad news is that many details of this transition are obscure because of the paucity of the fossil and archaeological records.94
As for the "good news," they still admit: "although we lack many details about exactly how, when, and where the transition occurred from Australopithecus to Homo, we have sufficient data from before and after the transition to make some inferences about the overall nature of key changes that did occur."95 In other words, the fossil record provides ape-like australopithecines ("before"), and human-like Homo ("after"), but not fossils documenting a transition between them. In the absence of intermediates, we're left with "inferences" of a transition based strictly upon the assumption of Darwinian evolution. One commentator proposed the evidence implies a "big bang theory" of the appearance of our genus Homo.96 This does not make for a compelling evolutionary account of human origins.97
Rather than showing gradual Darwinian evolution, the history of life shows a pattern of explosions where new fossil forms come into existence without clear evolutionary precursors. Evolutionary anthropologist Jeffrey Schwartz summarizes the problem:
[W]e are still in the dark about the origin of most major groups of organisms. They appear in the fossil record as Athena did from the head of Zeus -- full-blown and raring to go, in contradiction to Darwin's depiction of evolution as resulting from the gradual accumulation of countless infinitesimally minute variations. . ."98
This poses a major challenge to Darwinian evolution, including the view that all animals are related through common ancestry.
[65.] Charles Darwin, The Origin of Species (1859), p. 292 (reprint, London: Penguin Group, 1985).
[68.] Stephen Jay Gould, "Is a new and general theory of evolution emerging?" Paleobiology, 6(1): 119-130 (1980).
[69.] Charles Darwin, The Origin of Species (1859), p. 292 (reprint, London: Penguin Group, 1985).
[70.] Stephen Jay Gould, "Evolution's erratic pace," Natural History, 86(5): 12-16, (May, 1977).
[71.] M. J. Benton, M. A. Wills, and R. Hitchin, "Quality of the fossil record through time," Nature, 403: 534-536 (Feb. 3, 2000).
[72.] Mike Foote, "Sampling, Taxonomic Description, and Our Evolving Knowledge of Morphological Diversity," Paleobiology, 23: 181-206 (Spring, 1997).
[73.] Niles Eldredge and Ian Tattersall, The Myths of Human Evolution, p. 59 (New York: Columbia University Press, 1982).
[74.] David S. Woodruff, "Evolution: The Paleobiological View," Science, 208: 716-717 (May 16, 1980).
[75.] C.P. Hickman, L.S. Roberts, and F.M. Hickman, Integrated Principles of Zoology, p. 866 (Times Mirror/Moseby College Publishing, 1988, 8th ed).
[76.] R.S.K. Barnes, P. Calow and P.J.W. Olive, The Invertebrates: A New Synthesis, pp. 9-10 (3rd ed., Blackwell Sci. Publications, 2001).
[77.] Robert L. Carroll, "Towards a new evolutionary synthesis," Trends in Ecology and Evolution, 15(1):27-32 (2000).
[78.] Jaume Bagu�a and Jordi Garcia-Fern�ndez, "Evo-Devo: the Long and Winding Road," International Journal of Developmental Biology, 47:705-713 (2003) (internal citations removed).
[79.] Kevin J. Peterson, Michael R. Dietrich and Mark A. McPeek, "MicroRNAs and metazoan macroevolution: insights into canalization, complexity, and the Cambrian explosion," BioEssays, 31 (7):736-747 (2009).
[80.] Arthur N. Strahler, Science and Earth History: The Evolution/Creation Controversy, pp. 408-409 (New York: Prometheus Books, 1987).
[81.] Richard M. Bateman, Peter R. Crane, William A. DiMichele, Paul R. Kenrick, Nick P. Rowe, Thomas Speck, and William E. Stein, "Early Evolution of Land Plants: Phylogeny, Physiology, and Ecology of the Primary Terrestrial Radiation," Annual Review of Ecology and Systematics, 29: 263-292 (1998).
[82.] Stefanie De Bodt, Steven Maere, and Yves Van de Peer, "Genome duplication and the origin of angiosperms," Trends in Ecology and Evolution, 20:591-597 (2005).
[83.] Niles Eldredge, The Monkey Business: A Scientist Looks at Creationism (New York: Washington Square Press, 1982), 65.
[84.] See Alan Cooper and Richard Fortey, "Evolutionary Explosions and the Phylogenetic Fuse," Trends in Ecology and Evolution, 13 (April, 1998): 151-156; Frank B. Gill, Ornithology, 3rd ed. (New York: W.H. Freeman, 2007), 42.
[85.] Alan Cooper and Richard Fortey, "Evolutionary Explosions and the Phylogenetic Fuse," Trends in Ecology and Evolution, 13: 151-156 (April, 1998).
[86.] J.G.M. Thewissen and Sunil Bajpai, "Whale Origins as a Poster Child for Maccroevolution," BioEssays, 51: 1037-1049 (December, 2001).
[87.] Philip Gingerich, "Fossils and the Origin of Whales," ActionBioScience.org (December, 2006), http://www.actionbioscience.org/evolution/gingerich.html
[88.] List provided courtesy of Dr. Richard Sternberg.
[89.] Alan Feduccia, "'Big bang' for tertiary birds?," Trends in Ecology and Evolution, 18: 172-176 (2003).
[90.] See Walter James ReMine, The Biotic Message: Evolution Versus Message Theory (Saint Paul: MN, Saint Paul Science, 1983).
[91.] Private communication with Richard Sternberg.
[92.] Ernst Mayr, What Makes Biology Unique?, p. 198 (Cambridge University Press, 2004).
[93.] John Hawks, Keith Hunley, Sang-Hee Lee, and Milford Wolpoff, "Population Bottlenecks and Pleistocene Human Evolution," Journal of Molecular Biology and Evolution, 17(1):2-22 (2000).
[94.] Daniel E. Lieberman, David R. Pilbeam, and Richard W. Wrangham, "The Transition from Australopithecus to Homo," Transitions in Prehistory: Essays in Honor of Ofer Bar-Yosef, p. 1 (John J. Shea and Daniel E. Lieberman eds., Oxbow Books, 2009) (internal citations removed).
[96.] "New study suggests big bang theory of human evolution," (January 10, 2000) at http://www.umich.edu/~newsinfo/Releases/2000/Jan00/r011000b.html
[97.] For a more detailed discussion of the fossil evidence and human origins, see Casey Luskin, "Human Origins and the Fossil Record," pp. 45-83 in Science and Human Origins (Discovery Institute Press, 2012).
[98.] Jeffrewy Schwartz, Sudden Origins: Fossils, Genes, and the Emergence of Species, p. 3 (Wiley, 1999).