The Fossil Record
Fossils are said to document the gradual transitions between major groups that the theory predicts. What do the rocks actually show?
Paleontology
The fossil record contains real fossils with mixed features, and some were found where predicted. What it does not show is the lineages themselves: ancestry is inferred, major animal groups appear abruptly, and most species stay the same for as long as they are found.
The reasoning behind each grade is in Explore, one claim card at a time.
Fossils with intermediate features existObserved, catalogued, sometimes predicted.
They document ancestor-to-descendant lineagesInferred; contradicted in places by the order of appearance.
Gaps are explained by poor preservationPosits fossils that have not been found.
On both readings, the fossil pattern is shown to fit the favoured explanation more often than it is used to test it. The cards ask, in each case, what result would tell the explanations apart.
Gaps, abrupt appearances and stasis are each given an explanation after the fact. Whether those explanations made predictions of their own is the question each card asks.
- 1 clear · 3 possible
- 4 possible
- 2 possible
- 1 possible
- 1 possible
Both readings are checked. How it works →
Darwin reasoned that “innumerable transitional forms must have existed,” and asked why we do not find them “embedded in countless numbers in the crust of the earth” (Origin, ch. 6). He admitted that the record of his day did not show them, and blamed its imperfection. A century and a half of collecting later, this pillar asks three questions.
Do the celebrated transitional series show what they are said to show? Is the sudden appearance of animal body plans in the Cambrian really an artefact of poor preservation? And what should we make of stasis, the observation that most fossil species change little from first appearance to last?
In a recent-creation framework, most of the fossil-bearing rock is usually read as the record of a global catastrophe, not of slow ages. That reading belongs to Pillar 1 (Deep Time). Here we examine the record on its own terms, as the textbooks present it.
Claim cards
- № 2.01“Transitional fossil series show gradual change between major groups.”Fossils with intermediate features are real, and some were found where predicted. Do they document the lineages they are said to?5BD
- № 2.02“The sudden appearance of animal body plans in the Cambrian reflects an incomplete fossil record.”Most animal phyla appear in a geologically brief window, without clear ancestors. Are the ancestors missing because they were never preserved?3BD
- № 2.03“Long stasis in fossil species is consistent with gradual evolution.”Most fossil species change little for as long as they are found. How does a theory of gradual change accommodate that?2BD
Primary literature
- Budd GE, Jensen S. “A critical reappraisal of the fossil record of the bilaterian phyla.” Biological Reviews 75:253–295 (2000).Cited in № 2.02B
- Daeschler EB, Shubin NH, Jenkins FA. “A Devonian tetrapod-like fish and the evolution of the tetrapod body plan.” Nature 440:757–763 (2006).Cited in № 2.01B
- Eldredge N, Gould SJ. “Punctuated equilibria: an alternative to phyletic gradualism.” In Schopf TJM (ed.), Models in Paleobiology, pp. 82–115. Freeman, Cooper (1972).Cited in № 2.03C
- Erwin DH, Laflamme M, Tweedt SM, Sperling EA, Pisani D, Peterson KJ. “The Cambrian conundrum: early divergence and later ecological success in the early history of animals.” Science 334:1091–1097 (2011).Cited in № 2.02C
- Erwin DH, Valentine JW. The Cambrian Explosion: The Construction of Animal Biodiversity. Roberts & Co. (2013).Cited in № 2.02C
- Estes S, Arnold SJ. “Resolving the paradox of stasis: models with stabilizing selection explain evolutionary divergence on all timescales.” American Naturalist 169:227–244 (2007).Cited in № 2.03C
- Fedonkin MA, Waggoner BM. “The Late Precambrian fossil Kimberella is a mollusc-like bilaterian organism.” Nature 388:868–871 (1997).Cited in № 2.02C
- Gingerich PD, et al. “Origin of whales from early artiodactyls: hands and feet of Eocene Protocetidae from Pakistan.” Science 293:2239–2242 (2001).Cited in № 2.01B
- Gingerich PD, Smith BH, Simons EL. “Hind limbs of Eocene Basilosaurus: evidence of feet in whales.” Science 249:154–157 (1990).Cited in № 2.01B
- Gould SJ, Eldredge N. “Punctuated equilibria: the tempo and mode of evolution reconsidered.” Paleobiology 3:115–151 (1977).Cited in № 2.03C
- Hunt G. “The relative importance of directional change, random walks, and stasis in the evolution of fossil lineages.” PNAS 104:18404–18408 (2007).Cited in № 2.03B
- Lucas SG. “Thinopus and a critical review of Devonian tetrapod footprints.” Ichnos 22:136–154 (2015).Cited in № 2.01C
- MacFadden BJ. “Fossil horses—evidence for evolution.” Science 307:1728–1730 (2005).Cited in № 2.01B
- Shubin N. Your Inner Fish. Pantheon (2008).Cited in № 2.01C
- Smith JLB. “A living fish of Mesozoic type.” Nature 143:455–456 (1939).Cited in № 2.03B
- Thewissen JGM, Hussain ST, Arif M. “Fossil evidence for the origin of aquatic locomotion in archaeocete whales.” Science 263:210–212 (1994).Cited in № 2.01B
- Darwin C. On the Origin of Species, ch. 9, “On the imperfection of the geological record.” John Murray (1859).Cited in № 2.02C
- Gee H. In Search of Deep Time. Free Press (1999).Cited in № 2.01C
- Gould SJ. “Evolution's erratic pace.” Natural History 86(5) (1977).Cited in № 2.03C
- Meyer SC. Darwin's Doubt. HarperOne (2013).Cited in № 2.02C
- Niedźwiedzki G, et al. “Tetrapod trackways from the early Middle Devonian period of Poland.” Nature 463:43–48 (2010).Cited in № 2.01B
- Wells J. Icons of Evolution. Regnery (2000).Cited in № 2.01C
- Xiao S, Zhang Y, Knoll AH. “Three-dimensional preservation of algae and animal embryos in a Neoproterozoic phosphorite.” Nature 391:553–558 (1998).Cited in № 2.02B
Source grades are provisional. The Evidence Evaluator (next phase) will publish a full, challengeable evaluation for each.