Sunday, 2 March 2014

Cthulhu Lives!

New Octopus-like Protists in Termite Guts Named for HP Lovecraft Cosmic Monster ‘Cthulhu’ | The Artful Amoeba, Scientific American Blog Network

As everyone knows, Cthulhu is a tentacle-faced titanic god-monster who sleeps in a mythic undersea lair called R’lyheh, dreaming of the day he will emerge to destroy humanity. We'll, everyone who reads H.P. Lovecraft's stories knows.

Our little Cthulhu (Cthulhu macrofasciculumque, that is) is rather smaller and may not have such grandiose dreams as the fictional one but inhabits a strange lair, has tentacles and is at least real. The strange lair it inhabits is the gut of a Cuban subterranean termite (Prorhinotermes simplex) and termite guts are just about as strange as it gets on Earth, even allowing for the deep, dark recesses of the Pacific floor.

The thing about termites and their guts is that termites live almost entirely on the cellulose and lignin of dead wood, which are notoriously difficult to digest, being a highly stable large polymers of glucose. What termites have done is to harness the huge evolutionary power of single-celled organisms with their rapid generation time, which gives them great powers to solve complex problems using nothing but the genetic algorithm - problems like how to digest cellulose. This worked for termites and continues to work perfectly well, so there has been no evolutionary pressure on the termite genes to evolve their own solution. Genes will form alliances with whatever works and are not limited to those in the animal they happen to find themselves in. So, termites and their gut biome have become inextricably bound together by evolution, just as we have with our gut biome, as I blogged about earlier.

Termites are not the only animals to solve this problem that way. Many ruminants who live on grass and leaves use the same method and have guts modified to act like fermentation chambers where bacteria and other protist do much of the work in return for a sheltered environment and a supply of raw materials.

Each species of termite acts like an isolated ecosystem with very little contact with the outside world and, not surprisingly, evolution has proceeded in its own direction there, producing a whole range of organisms not found elsewhere and often only very remotely connected with common ancestors of related species.

C. macrofasciculumque has a bunch of 20 flagella which it uses for propulsion by paddling. Unlike normal flagella which rotate at the rear like a propeller, these flagella are at the front and row rather like the arms in a breaststroke. They come together on the forward stroke to reduce resistance and spread out on the backward, power stroke. There may also be a standard propeller flagellum at the rear.

Meanwhile, in a related species of the Cuban subterranean termite, the Eastern subterranean termite (Reticulitermes flavipes), we find another very similar, and clearly related (though not that closely, hence it has a different generic name) protist, which has been named after Cthulhu's secret daughter (the fictional Cthulhu, that is). Cthylla microfasciculumque does the same job in R. flavipes as its counterpart does in P. simplex but it has only five tentacles compared to its better-endowed relative and has a definite propeller flagellum.

These protists are part of a much larger group called the parabasalids which includes not only simple, single-celled species but some bigger, multicellular organisms, and one, Trichomonas vaginalis, which is a sexually transmitted parasite in humans. They all appear to have evolved from a single common ancestor and are usually associated with complex, multicellular animals, either parasitically or symbiotically. It appears that the bigger ones may have evolved several times from the smaller ones.

It almost seems churlish to ask creationists and intelligent designers, what on Earth they imagine their 'Intelligent Designer' was thinking of when it came up with these organisms and this system for digesting dead wood, when it could have provided termites and other plant-eaters with a well-designed digestive tract in the first place.

I doubt I'll get any, but answers below, please.

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1 comment :

  1. One might also ask them why different species of termites have developed so many different soldier types and nest forms. Why nasutes in some and mandibulates in others, for example? You'd almost think the Intelligent Designer somehow thought giving soldier termites jaws so big they couldn't feed themselves was a good joke or something.

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