Baby baleen whales have teeth (until they lose them)

As a final note on my series on whales, I’ll mention an interesting tidbit about teeth. Despite the fact that baleen whales lack teeth entirely, fetal baleen whales do have tooth buds that never fully develop.

demere-tooth-buds_2_2

This ties in nicely with both the fossil and genetic evidence that baleen whales descended from species that lost their teeth as they transitioned to filter feeding.

Questions for creationists

Why would God create baleen whales with tooth buds that fail to fully develop? Is it a coincidence that whales have tooth pseudogenes and putative transitional fossils showing evidence of losing teeth?

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3 thoughts on “Baby baleen whales have teeth (until they lose them)

  1. Creationists like myself are I think generally open to the possibility of negative evolution – ie loss of organs, functions and so on. See this, for example:

    ‘Are we really certain that these are teeth that never erupted or tooth buds as they are described? And if they are (as they appear to be) does their existence prove Baleen whales were originally created having teeth that they subsequently lost?’ at http://creationstudies.org/articles/science/life-science/206-whales-lose-teeth

    Andrew

    1. Hi Andrew, thank you for your comment!

      Yes, I’m becoming increasingly aware of the acceptance of negative (we usually call it regressive) evolution in the Creationist community. However, I haven’t seen this position very clearly articulated anywhere. Rather it seems to generally be ad hoc (though I suppose perhaps I haven’t looked hard enough). Maybe you can point me to a relevant source, unless like me this is just something you’ve noticed in the community?

      But even if this concept is acceptable to Creationists, it does lead to some major implications about the extent of evolution that has occurred. So for this example, fetal baleen whales have tooth buds that are absorbed before erupting and baleen whale genomes have remnants of multiple tooth genes. So this would support the idea that baleen whales lost teeth over time. Furthermore, baleen whales share the same loss-of-function mutations in at least one of these tooth genes, suggesting that the gene (and teeth) were knocked out in a common ancestor: https://evolutionforskeptics.wordpress.com/2014/11/08/pseudogenes-enamelless-mammals-and-toothless-turtles-and-birds-have-enamel-gene-remnants/

      Furthermore, the geological record includes fossils of whales with teeth and baleen side-by-side, and these appear in rocks that date to after the first toothed whales and before the first baleen whales (e.g., Aetiocetus): https://evolutionforskeptics.wordpress.com/2014/05/18/transitional-fossils-3-through-11-from-land-mammals-to-the-ancestor-of-whales/

      So if regressive evolution is acceptable for Creationism, this makes me wonder what sort of scenario incorporates all of these data into a Creationist framework. Did the Creator create whales with teeth and then some evolved baleen (presumably not acceptable)? Or did It create some whales with both teeth and baleen and the whales lost the teeth? Why create teeth in the first place if they just ended up losing it?

      If this all happened in the last 6000-10000 years, how did it happen so quickly? Whales have notoriously few, slow-growing offspring that are slow to sexual maturity, meaning that they evolve extremely slowly. Yet, evolution would have had to act extremely quickly by some unknown mechanism to lead to the loss of teeth, and accumulate loss-of-function mutations in multiple tooth genes, to have this occur in such a short time frame (especially if this happened in an ancestor of baleen whales, rather than a single lineage in the past 6000-10000 years).

      Plus, the whales like Aetiocetus look similar to modern baleen whales, yet they are very distinct from modern baleen whales (in some ways they look more similar to what we interpret to be ancient whales). We haven’t found any fossils that look like a blue whale, humpback whale or bowhead whale with teeth and baleen side-by-side.

      So while I appreciate that regressive evolution can be accepted by Creationists (e.g., perhaps in cave animals), my impression is that it often raises many additional questions that seem to work contrary to the Creationist model.

  2. Pingback: Toothless, baleen whales have remnants of tooth genes – Evolution For Skeptics

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