Wild Things

Bizarre crea­tures like the tiny tardi­grade and the won­drous oc­to­pus have in­spired some out-of-this-world ori­gin the­o­ries… lit­er­ally

Canadian Wildlife - - CONTENTS - By Jay In­gram

They Came from Outer Space?! Bizarre crea­tures like the tiny tardi­grade have in­spired some out-of-this-world the­o­ries

Ire­cently came across a head­line sug­gest­ing that oc­to­puses were aliens. They do have eerie abil­i­ties, but aliens? Even more sur­pris­ing, the idea was ex­pressed in a sci­en­tific pa­per: “Cause of Cam­brian Ex­plo­sion — Ter­res­trial or Cos­mic?” pub­lished in the jour­nal Progress in Bio­physics and Molec­u­lar Bi­ol­ogy.

There’s a tan­gled tale here: for one thing, al­most all the 30 au­thors cited of­ten have made bold and con­tro­ver­sial claims that chal­lenge widely held sci­en­tific views. Other sci­en­tists ig­nore them, some de­bate them, but very few agree with them.

On the other hand, this ar­ti­cle ties to­gether so many in­tensely in­ter­est­ing pieces of sci­ence, from the ori­gin of life, to the search for hab­it­able plan­ets in the galaxy, to some true bi­o­log­i­cal puz­zles. Two of these puz­zles are an­i­mals that the au­thors of the pa­per as­sert have come from space: the tardi­grade and the oc­to­pus.

Ob­vi­ously, these are very dif­fer­ent and barely re­lated an­i­mals, but each pro­vides a piece of an over­all ar­gu­ment. Back in the 1980s, the late — and in­deed great — as­tronomer Fred Hoyle teamed up with as­tro­bi­ol­o­gist Chan­dra Wick­ra­mas­inghe to make the hereti­cal claim that life didn’t orig­i­nate on Earth, but ar­rived on­board comet tails and meteoroids, show­ers and show­ers of them.

Such life would have been obliged to re­main frozen and soaked in ra­di­a­tion in space for per­haps hun­dreds of mil­lions of years. Tardi­grades, barely vis­i­ble eight­legged “mi­cro-an­i­mals” that look like a car­i­ca­ture of a bear the size of the pe­riod at the end of this sen­tence, ap­pear to have all the at­tributes nec­es­sary to do that. (See Alanna Mitchell’s col­umn in Cana­dian Wildlife Jan­uary/fe­bru­ary 2016, reprinted on­line.) They’re re­sis­tant to tem­per­a­tures as low as 0.5 de­grees above ab­so­lute zero (for sev­eral hours) or as high as 150 Cel­sius, ra­di­a­tion doses equiv­a­lent to those in space, and crush­ing pres­sure six times that near the bot­tom of the Mar­i­ana Trench.

The au­thors of the jour­nal pa­per ask why an Earth-dwelling an­i­mal would pos­sess such un­earthly equal­i­ties. What value would nat­u­ral selec­tion have seen in the abil­ity to with­stand tem­per­a­tures or ra­di­a­tion rarely or never seen on Earth? The or­tho­dox an­swer is that these lit­tle crea­tures have adapted to the va­ri­ety of ex­treme en­vi­ron­men­tal changes they ex­pe­ri­ence in var­i­ous habi­tats on Earth — they can be found prac­ti­cally ev­ery­where. But for the sci­en­tists in this case, that’s just not enough. For them, tardi­grades had to have come from an ex­treme en­vi­ron­ment some­where in space. The ques­tion of the source of these adap­ta­tions is in­deed worth ask­ing, but only the most fer­vent be­liev­ers in “pansper­mia” (life com­ing from outer space) would leap to that con­clu­sion.

The more fa­mil­iar oc­to­pus is also no­table for its ar­ray of amaz­ing fea­tures: arms that pretty much have their own ner­vous sys­tem and can be­have in­de­pen­dently of the oc­to­pus brain, the abil­ity to match the colour and tex­ture of its back­ground, and amaz­ing smarts that el­e­vate it to the same in­tel­lec­tual league as pri­mates. As in the case of the tardi­grade, the his­tory of these adap­ta­tions is mys­te­ri­ous, be­cause the cham­bered nau­tilus, the most an­cient of the oc­to­pus clan, shares none of these ad­vanced fea­tures.

The oc­to­pus genome pro­vides its own share of sur­prises and mys­ter­ies. In par­tic­u­lar, it has the molec­u­lar ma­chin­ery to edit the prod­ucts of its genes with­out ac­tu­ally chang­ing (or mu­tat­ing) the genes them­selves. In one sense then, its genome is very con­ser­va­tive and evolves slowly. But on the other hand, the an­i­mals can make sub­stan­tial and rel­a­tively sud­den changes to the ar­ray of pro­teins made by those genes.

This ma­chin­ery is not unique to oc­to­puses — we hu­mans have it too — but in most other species, in­clud­ing hu­mans, it’s a tiny piece of ge­nomic pro­duc­tion, whereas in the oc­to­pus it is cen­tral to their me­tab­o­lism. And this edit­ing is par­tic­u­larly ac­tive with genes re­spon­si­ble for the oc­to­pus ner­vous sys­tem.

How is it that in this re­gard they are so dif­fer­ent from most forms of life? The au­thors of the pa­per sug­gest this ge­netic ma­chin­ery came from space “most plau­si­bly as an al­ready co­her­ent group of func­tion­ing genes within (say) cry­op­re­served and ma­trix-pro­tected fer­til­ized Oc­to­pus eggs.” That’s right: oc­to­pus eggs from space.

Hav­ing thrown two in­cred­i­ble claims at you, I ad­mit I haven’t even tack­led the main ar­gu­ment of the ar­ti­cle: that an ex­plo­sion of viruses more than 500 mil­lion years ago prompted what’s called the Cam­brian ex­plo­sion, the sud­den ap­pear­ance in the fos­sil record of most of the an­ces­tors of modern life — the kind of fos­sils found in British Columbia’s Burgess Shale.

But I don’t have to; the tardi­grade and the oc­to­pus are enough to re­mind us all that there is, and al­ways will be, a per­sis­tent but tiny mi­nor­ity of sci­en­tists who think the or­tho­dox view, that all life on Earth evolved right here, is just too parochial.

IN THE 1980S, TWO LEAD­ING SPACE SCI­EN­TISTS CLAIMED THAT LIFE DIDN’T ORIG­I­NATE ON EARTH, BUT AR­RIVED ON­BOARD COMET TAILS AND METEOROIDS. NOW A LEAD­ING JOUR­NAL TAKES UP THE CAUSE

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