Sunday, October 17, 2004
Do they still teach this evolution stuff anyway?
At the moment I am about a week and a half away from the start of another round of final exams. Obviously studying takes up most of my time at the moment and as such I don’t have much time to get into interesting sidetracks to blog about and the stuff I’m studying just isn’t all that interesting for the layman audience I try and aim Science and sensibility at. Having said that I thought it might be fun to do a little analysis of a few of my lectures in the same way that P.Z. Myers has of papers in an issue of the Journal Developmental Biology.
Dr Myers’ analysis was spurred by another analysis from a creationist suggesting that the day to day workings of biology and biologists really have very little to do with evolution. Very commonly creationists express this opinion to try and suggest evolution isn’t a central tenet of biology and can be safely laid aside without effecting our studies of the way organisms make a living. More specifically I’ve heard it suggested that universities “don’t even teach evolution outside of zoology/botany classes” and that in particular molecular and cell biologists could justifiably be creationists without rocking the boat. The fact is that all these claims are demonstrably false. Dr Myers’s analysis of the biological literature shows that most of biologist’s communications involve evolution or in the very least take it for granted. In this post I will take ten lectures from a course called “advanced cell biology” taught by three different professors to show that not only are universities still teaching "that stuff" but that evolution is central to our understanding of molecular and cell biology.
Full credit for the idea, colour scheme and criteria for decisions has to be given to P.Z Myers. Here are the categories a lecture could fall into:
| Blue lectures are explicit in their discussion of evolution, proposing evolutionary connections or even suggesting evolutionary histories for molecules or systems. The evolutionary aspect is seldom the major point, but it is discussed. |
| Green lectures treat evolution as implicit. They may compare systems that are conserved amongst different species and sequences and domains of proteins that are conserved between species and within families contained in the same genome. They don't specifically address evolutionary ideas but the comparisons take evolution for granted. |
| Gray lectures don't say anything one way or the other about evolutionary relationships. Most of these lectures are very specific in their scope. A creationist student wouldn't find anything objectionable in these lectures, but they don't provide any evidence for cretionism |
| Black lectures would be ones that directly discuss Intelligent Design or other anti-evolutionary ideas about science. As in P.Z. Myers' analysis this is a hypothetical category; none were taught. |
And here is a quick description of each lecture and how I chose which catergory to place it in.
| Lecture topic | Description/Justification of my designation |
|---|---|
| Signal transduction/Cell signalling | Lots of talk about conserved signalling pathways in cell signalling. Specfically lays out the phylogenetic relationship between various G-protein families |
| Purification of receptor proteins | Practical based lecture on how best to purify cell surface receptors. Includes the method of homology screening to isolate proteins related to one of known sequence |
| "Toxins Drugs and diseases of the GPCR signalling pathway" | Talks about a few of the many ways that that signalling pathways can go wrong (including 'pseudohypoparahyroidism') |
| Receptors for smell and bitter taste | The discovery of olfactory receptors was based on the idea that there would be a family of related receptors in olfactory epithelium (cf. this year's nobel prizes.)Bitter taste receptor discussion include phylogeny of bitter taste receptors and opsins in human genome |
| Orphan GPCRs | Discusses the implications of the ~140 G protein coupled receptors identified by the human genome project that have no known function. Their designation as GPCRs is based on their homolgy to other, known GPCRs |
| Cytoskeleton: Components constructon and regulation | Talks about the idea that the Intermediate fibres may be descendants of the nuclear lamins |
| Molecular motors and transport within the cell | Compares conserved features amongst myosin motors |
| Translocation of proteins to the various areas within the mitochondria/ nucleus (two lectures) | Talks about homologies between the various translocases used in this process |
| Cell cycle (two lectures) | Conserved features of the cell cycle, aspects of the cell cycle inferred from experiments in Yeasts Xenopus apply to many other species. Conservation of cyclins, cdks and other molecules across various species |
| Apoptosis (two lectures) | Where to start! Almost all knowledge of apoptosis based on C. elegans comaparisons comparisons of caspases from single species and entire classes of apoptosis genes in different species |
So there it is, out of ten lectures one could conceivable stand up as being independent evolution. Time and time again the notes I have taken form lectures show how the functional parts of molecules in cell biology are conserved across families within one species and homologous molecules in other species. In fact the resounding majority of the lectures make an effort to see the mechanism or molecule being studied in the light of its evolutionary history.
The cell cycle and apoptosis (programmed cell death) are two of the most central ideas in cell biology. In this course they were taught principally by scaling up the features described in ‘simple organisms’ like yeasts and C. elegans to the more complex systems in vertebrates and mammals. And, in fact, without accepting evolution our ability to learn about these important processes, both intimately linked with cancer, would be seriously handicapped