What follows is a summary of a longer article Why do we know that birds are living dinosaurs? published (in English) by AG Evolutionsbiologie, a German scientific association that deals with evolutionary biology and creationism.
The finding that birds are descendants of certain dinosaurs has been a scientific consensus for over 20 years. Only a very few experts still question it. In the publications of those who deny macroevolution and want to have it replaced by an “intelligent” origin (that is, creationists of various stripes), such criticism is clearly overrepresented. However, unlike the scientists they cite, creationists do not primarily cast doubt on the membership of birds in particular archosaur taxa. Rather, they want to see the evolutionary development as such questioned. They achieve this only by mixing the criticism of individual scientists with antiquated and factually incorrect ideas on evolution.
One of the creationists who is concerned with criticizing avian evolution is Reinhard Junker, former managing director of the German evangelical association Wort-und-Wissen. His argumentation is typical of creationist criticism. Since such criticism relies on antiquated views of evolution, numerous findings look like serious anomalies.
In this review, we explain why birds' ancestry from Mesozoic dinosaurs is a scientifically well-established fact. Afterwards, we discuss popular objections against this thesis presented by creationists like Reinhard Junker and by scientists like Alan Feduccia as well. We show that creationist criticism is working under a misunderstanding or misrepresentation of evolutionary theory. This line of reasoning is influential worldwide. It is representative of the whole creationist spectrum.
The ten main theses of our analysis are as follows:
- The statement that birds are the product of a long, evolutionary-historical process is logically independent of the question of how this evolution proceeded in detail. The evolution of birds and birds' ancestry from Mesozoic dinosaurs is essentially supported by the fact that we can put theropod fossils into a sequence in which their shape gradually takes on the appearance of modern birds. Given that descent, heritable variability, and speciation are observed facts, bird evolution (or evolution in general) would remain untouched even if we knew nothing about its mechanisms.
- Creationists allege a waiting time problem causing a very slow pace of evolution. Hence, in their eyes, evolutionary mechanisms are overstrained by producing the great diversity of avian forms “abruptly” in geologically short periods. However, their reasoning is quite wrong. First, creationists do not seem to have understood how novelties arise in evolution. For instance, evolution never faced the task of waiting until a “fixed and pre-specified target” was reached. Second, the evolvability of novelties, even of irreducibly complex systems, within short time periods is a well-corroborated and no longer reasonably disputable fact (see, for instance, HUNT 2007b; TONKIN et al. 2008; DE KRAKER & GERSHENZON 2011; SAUTER et al. 2012; TROTTER et al. 2014; YONA et al. 2018; RAWCLIFFE 2019; BEYER et al. 2022; NEUKAMM 2022).
- When it comes to the “abrupt” appearance of characters in the fossil record, the explanation of punctuated equilibria must be considered as well as the ambiguity of the term “abrupt”. When a paleontologist speaks of the “abrupt” appearance of a feature, he may still think of periods of millions of years. Here, the biased and fragmentary sedimentary record, both in time and in space, must be taken into account. Abrupt appearance may hence be a geological artifact.
- Creationists ignore the progress of evolutionary developmental biology (Evo-Devo) in solving specific problems. This includes, for example, the question of how the supposedly contradictory counting of fingers in some theropods (apparently, I-II-III) and birds (II-III-IV) fits together. Evo-Devo can also explain the capability for comparatively rapid convergent evolution of quite a few avian features.
- Evolution deniers portray the convergence problem as much more serious than it is. Despite widespread convergence and uncertainty about the position of some taxa, there is a remarkable consensus on the backbone structure of the family tree of the ancestors of birds and the relative hierarchical placement of almost all major clades that constitute this tree. Birds still lie in a deeply nested position within Theropoda (RAUHUT & FOTH 2020, p. 37).
- Contrary to creationists' reasoning, widespread convergences are not anomalies but rather a clear expectation of evolutionary theory when developmental biological background knowledge is considered (MCGHEE 2011, p. 7).
- For at least half a century, the idea that evolution must run continuously and linearly has not been compatible with contemporary knowledge of the processes of speciation and differentiation of species (MAHNER 1986, p. 68). Creationists do not seem to know that just these processes are accompanied by discontinuities, incongruities, and a zigzag course (such as reversions of traits in different lineages).
- Creationists place antiquated expectations on the nature of evolutionary transitional forms and claim to have recognized “contradictory” trait mosaics. Hence, they ignore that mosaic evolution is the result of genetic burdens (RIEDL 2003, p. 209) and lineage-splitting events (MAYR 1967, p. 465 f.).
- The claim that the features of the avian body plan could not have evolved isolated from each other is false. The theropod fossils can be placed in a sequence in which the “irreducibly complex overall organization” of birds resolves into a series of consecutive feature addition steps.
- Creationists seem not to understand cladogenesis; otherwise, they would not problematize the phylogenetic-stratigraphic discrepancy, i.e., the chronologically later appearance of some species with more primitive features in the fossil record. (For the attempt to compress the geological time scale by six orders of magnitude, see here).
We would particularly like to thank John HARSHMAN, a specialist in dinosaur evolution, who reviewed this paper and contributed to its accomplishment with his critical comments. Thanks also go to Matt YOUNG for editorial review. Furthermore, we give thanks to Prof. Oliver RAUHUT for his statements, which he allowed us to reproduce in section C.11. We would also like to thank Dandan WU from the Peking Natural Science Organization (PNSO) and Stefan PROCHASKA from SchuBu Systems GmbH for their permission to reproduce their images.
About the authors.
Prof. Dr. Andreas Beyer studied biology at the Ruhr University in Bochum (Germany) with a focus on biochemistry, physiology, cytology and microbiology. Doctorate on the topic “molecular biological characterization of the AAA gene family, a new group of putative ATPases.” Research on the phosphorylation of phosphorylase kinase at the Institute for Physiological Chemistry at the Ruhr University. Applied research in various industrial projects. Lecturer at the Westfälische Hochschule Gelsenkirchen, Bocholt, Recklinghausen (Germany) as Professor of Molecular Biology. Chairman of the working group “AG Evolutionsbiologie” which is associated with the German Association of Biologists (VBio).
Martin Neukamm is a German chemist and managing editor of the AG Evolutionsbiologie, a German scientific association that deals with evolutionary biology and creationism. He has published various articles and books on evolution and creationism in the German language.