How often do biologists talk about this evolution stuff, anyway?
info
Format for printing
Pirate mode
Creationists like to say that evolution's influence is dying and that it is of little importance to doing biology. They take advantage of the layperson's lack of familiarity with the scientific literature to argue that evolution has little relevance, or that Dobzhansky's aphorism that "nothing makes sense in biology except in the light of evolution" is false. Anyone who actually reads the biological literature, though, will come away with exactly the opposite impression: the journals are full of references to evolution, even in disciplines and journals that don't have "evolution" in their title. The concept is central; it's as ubiquitous as references to "genes".
To demonstrate, I've carried out a quick exercise, similar to one I've done before. The latest copy of one of the major journals in my field, Developmental Biology, just arrived in my mailbox. It's a top-notch journal, affiliated with our biggest organization, the Society for Developmental Biology. It's not evolutionary biology directly, but there has been an increasing awareness of the significance of evolution to our field, so it's a good representative of an expanding, hot field which is experiencing some synergy with other disciplines.
What I did was to quickly skim through each of the 21 articles in Volume 274, Issue 2, of Developmental Biology, and ask myself how much each article depended upon or discussed the topic of evolution. I categorized and color-coded each one by the following criteria:
| Blue articles are explicit in their discussion of evolution, proposing evolutionary connections or even testing evolutionary hypotheses. The evolutionary aspect may not be the major point of the paper, but it is discussed. |
| Green articles treat evolution as implicit; they may work with molecules homologous between different species, but they don't specifically address evolutionary ideas. This is not to say that they have a lesser commitment to evolution, but more that they take it for granted. |
| Gray articles don't say anything one way or the other about evolutionary relationships. Most often these are papers that are tightly focused on analysis of data from a single species. It's entirely possible to imagine a creationist writing these, but of course there is no implication that the authors deny evolution. |
| Black articles would be ones that directly discuss Intelligent Design or other anti-evolutionary ideas about science. This is a hypothetical category; none were found. |
Here is my classification of each of those articles, with a brief justification for why I put each in its particular category.
| Paper | Justification |
|---|---|
| Cellular recruitment and the development of the myocardium (Review article) Leonard M. Eisenberg and Roger R. Markwald |
"the key to understanding the distinct neural crest contributions to heart development between zebrafish and higher vertebrates relates to the mechanisms that determine their migration patterns among species", but also says that detailed discussion of the issue is beyond the scope of this particular paper |
| Early neural cell death: dying to become neurons (Review article) Weeteck Yeo and Jean Gautier |
discusses signalling cascade for apoptosis in C. elegans, and draws analogies with vertebrate cascade that has yet to be demonstrated (a prediction based on evolution);extensive phylogenetic comparisons |
| The zebrafish onecut gene hnf-6 functions in an evolutionarily conserved genetic pathway that regulates vertebrate biliary development Randolph P. Matthews, Kristin Lorent, Pierre Russo and Michael Pack |
discusses bile duct formation as part of an evolutionarily conserved pathway |
| WAVE/SCAR, a multifunctional complex coordinating different aspects of neuronal connectivity Annette Schenck, Abrar Qurashi, Pilar Carrera, Barbara Bardoni, Céline Diebold, Eyal Schejter, Jean-Louis Mandel and Angela Giangrande |
focused on the role of the WAVE/SCAR complex in Drosophila; briefly mentions that these same genes also play a role in human mental retardation |
| SOX9 is up-regulated by the transient expression of SRY specifically in Sertoli cell precursors Ryohei Sekido, Isabelle Bar, Véronica Narváez, Graeme Penny and Robin Lovell-Badge |
only discusses SRY/SOX9 activity in mouse cells |
| Embryonic development of the Drosophila corpus cardiacum, a neuroendocrine gland with similarity to the vertebrate pituitary, is controlled by sine oculis and glass Begona De Velasco, Jennifer Shen, Sheryllene Go and Volker Hartenstein |
discusses conserved pathways between flies and vertebrates in neuroendocrine development |
| Requirement for Mab21l2 during development of murine retina and ventral body wall Ryuichi Yamada, Yoko Mizutani-Koseki, Haruhiko Koseki and Naoki Takahashi |
this is a mouse homolog to a C. elegans gene |
| Multi-state, 4-aminopyridine-sensitive ion channels in human spermatozoa Y. Gu, J.C. Kirkman-Brown, Y. Korchev, C.L.R Barratt and S.J. Publicover |
channel physiology in human sperm only |
| Differences in expression pattern and function between zebrafish hoxc13 orthologs: recruitment of Hoxc13b into an early embryonic role Ryan Thummel, Li Li, Carmen Tanase, Michael P. Sarras, Jr. and Alan R. Godwin |
testing predictions of theories of gene duplication and evolution in vertebrates |
| Coordinate regulation of neural tube patterning and proliferation by TGFβ and WNT activity Catherine Chesnutt, Laura W. Burrus, Anthony M.C. Brown and Lee Niswander |
TGFβ and WNT are found to have similar roles in diverse organisms, but the paper only discusses the specifics of its role in chick |
| The epaxial–hypaxial subdivision of the avian somite Louise Cheng, Lúcia E. Alvares, Mohi U. Ahmed, Amira S. El-Hanfy and Susanne Dietrich |
Many details focused exclusively on chick, but introduced as part of an effort to resolve differences in somite organization within the gnathostomes |
| Mammalian phospholipase Cζ induces oocyte activation from the sperm perinuclear matrix Satoko Fujimoto, Naoko Yoshida, Tomoyuki Fukui, Manami Amanai, Toshiaki Isobe, Chiharu Itagaki, Tomonori Izumi and Anthony C.F. Perry |
details of a molecule in mouse oocyte activation |
| Specific PKC isoforms regulate blastocoel formation during mouse preimplantation development Judith J. Eckert, Amanda McCallum, Andrew Mears, Martin G. Rumsby, Iain T. Cameron and Tom P. Fleming |
details of a molecule in mouse blastocyst cavitation |
| RNT-1, the C. elegans homologue of mammalian RUNX transcription factors, regulates body size and male tail development Yon-Ju Ji, Seunghee Nam, Yun-Hye Jin, Eun-Jung Cha, Kyeong-Sook Lee, Kyu-Yeong Choi, Hyun-Ok Song, Junho Lee, Suk-Chul Bae and Joohong Ahnn |
mostly focused on only C. elegans, only a brief mention of mammalian homology (and would have been more interesting with more discussion of the mammalian connection!) |
| Formin3 is required for assembly of the F-actin structure that mediates tracheal fusion in Drosophila Hiromasa Tanaka, Etsuko Takasu, Toshiro Aigaki, Kagayaki Kato, Shigeo Hayashi and Akinao Nose |
highly conserved gene family found in yeast and vertebrates, too |
| Enkurin is a novel calmodulin and TRPC channel binding protein in sperm Keith A. Sutton, Melissa K. Jungnickel, Yanli Wang, Kay Cullen, Stephen Lambert and Harvey M. Florman |
introduction is all about PLC and TRPC activation and Ca++ entry as a universal property in a wide range of animal sperm |
| R11: a cis-regulatory node of the sea urchin embryo gene network that controls early expression of SpDelta in micromeres Roger Revilla-i-Domingo, Takuya Minokawa and Eric H. Davidson |
very detailed, mechanistic analysis of regulation of a specific gene, with a comparison of two urchin species that diverged 50 million years ago |
| Tissue-specific expression of FoxD reporter constructs in amphioxus embryos Jr-Kai Yu, Nicholas D. Holland and Linda Z. Holland |
this is all about molecules central to the evolution of vertebrate innovations, such as neural crest |
| Discovery of genes implicated in placode formation Kathryn L. McCabe, Andrea Manzo, Laura S. Gammill and Marianne Bronner-Fraser |
commonalities of gene expression support the hypothesis that neural crest and placodal cells evolved from a common cell type |
| Identification of downstream genes of the ascidian muscle determinant gene Ci-macho1 Kasumi Yagi, Nori Satoh and Yutaka Satou |
evolution of Ciona Zic zinc-finger genes; relationship to patterning genes in flies and vertebrates |
| Differential requirement for ptf1a in endocrine and exocrine lineages of developing zebrafish pancreas John W. Lin, Andrew V. Biankin, Marko E. Horb, Bidyut Ghosh, Nijaguna B. Prasad, Nelson S. Yee, Michael A. Pack and Steven D. Leach |
phylogenetic comparison of genes involved in formation of the pancreas |
Twelve articles explicitly address issues in evolution. Four simply assume evolution, using molecules found in different lineages without bothering to discuss the phylogenetic significance (although the Schenck article was borderline, in that it did mention it, but didn't deal with it much). Five were single species or even single molecule studies that didn't try to relate their results to a comparative picture (which is not a criticism of the work; they are good, detail-oriented papers). The distribution, that a clear majority of the papers contain a significant amount of consideration of evolutionary concepts, is typical of the journals I read.
I would also add that lacking a discussion of evolution in one paper on a subject doesn't mean that the subject as a whole is lacking the concept. The Gu paper on sperm channel physiology is only talking about channel properties in one species, but people interested in that topic would also read the Sutton paper, which spends a fair amount of spacing discussing the phylogenetic significance of channel activation molecules.
None of the papers had or could say anything about Intelligent Design. Creationism simply isn't a legitimate or useful component of our analysis of the data.
I don't expect high school students to be able to open up an issue of Developmental Biology and be able to read any article; I think everyone can tell from the titles that there is some rather esoteric stuff in there. But they will be grossly disadvantaged in learning this material later if they completely lack one of the basic conceptual foundations of the work, evolution. It really would be like trying to read the literature while disbelieving in those godless "genes", or that "catalysts" can't possibly work because they violate the laws of thermodynamics.
Dobzhansky was right.
There are some high school teachers and school board members who can't figure this out…unfortunately, the ones who argue against evolution in the classroom don't seem to be the ones who understand how biology is actually done.
What a nice exercise and unsurprisingly as well as wonderfully the codes (unlike the homeland security colors or ID) come with evidence that one may examine. I like that you point out there are times, e.g., in single species/molecular studies there is often no need to discuss them in terms of Dobzhansky's dictum but that they are understood in these terms by reading other related papers, a must. And is evolution alive and well, indeed getting better: you bet! Evolutionary concepts? You can't get along with out them if you are to understand the life sciences or the world. Thanks for taking time to do this so colorfully, too.