Proof of phytological principle

Image: Becker & Marin (2009)

Image: Becker & Marin (2009)

Sadly, we don’t have time machines that would per­mit us to go back and see ancient evol­u­tion in action. So we have to make do with such devices and stratagems as infer­ence, sur­mise, spec­u­la­tion, good honest-to-goodness old-fashioned guess­work, and invest­ig­at­ing modern-day equi­val­ents that might mimic the ori­ginal phe­nomenon. Take for instance col­on­isa­tion of the land by ‘plants’. Arguably, this was one of the most import­ant events in cre­ation of the modern-day planet we call home, but how could ‘terraphyte’s’ ancest­ors sur­vive a much drier land-living exist­ence and thus pave the way for a ter­restrial take-over? Trying to get a handle on early plant adapt­a­tion to land, Linda Graham et al. have stud­ied how well assumedly oblig­ately aquatic algae could sur­vive an ‘aeroter­restrial’ exist­ence (i.e. liv­ing on and in soil, or cov­er­ing sur­faces such as rocks and tree barks; http://​www​.alga​terra​.org/​A​T​5​.​htm). The group used ‘two spe­cies of the exper­i­ment­ally tract­able, com­plex strep­to­phyte algal genus Coleochaete’, chosen because it is one of the extant green algal gen­era most closely related to the embry­ophytes – the so-called ‘land plants’ ( see Burkhard Becker and Birger Marin’s Botanical Briefing in Annals of Botany)  – and there­fore a plaus­ible putat­ive palaeolo­gical plant pro­gen­itor. What they dis­covered sug­gests that ancient com­plex strep­to­phyte algae could grow and repro­duce in moist sub­aerial hab­it­ats, and per­sist through peri­ods of desic­ca­tion – as you’d need to in order to occupy a drier hab­itat. Consequently, land col­on­isa­tion could be envis­aged by ancient Coleochaete-like organ­isms (which are fresh­wa­ter aquat­ics). Which is good to know, and also accords with the very latest ideas in terms of identi­fy­ing the neb­u­lous ‘cru­cible of cre­ation’, which may not have been the oceans – as long thought – but fresh­wa­ter ponds, accord­ing to work by Armen Mulkidjanian et al. (PNAS). Whilst this may upset the apple-cart of received wis­dom in that field in chal­len­ging firmly held, long-cherished beliefs, at least it’s still arguing for an import­ant aquatic dimen­sion (even though it can be argued that it actu­ally pro­poses that life on Earth ori­gin­ated on land – but let’s leave fur­ther delib­er­a­tion thereon to the seman­ti­cists…). But! – and as poin­ted out by oth­ers – this 21st Century idea is remin­is­cent of the notion that evol­u­tion may have begun in a ‘warm little pond’, pos­ited by a cer­tain Mr C. Darwin in 1871. Which only goes to show that there’s prac­tic­ally noth­ing in bio­logy that has not already been cre­ated by CD (and that ideas about evol­u­tion just keep evolving!).

[Mr Cuttings thought he’d inven­ted the word ter­raphyte in pen­ning this item. Well, he had, but not ori­gin­ally it would seem. In a ‘cov­er­ing his back­side’ moment, an inter­net search has revealed that the term has been used pre­vi­ously by ‘aquetus’ – inter­est­ingly in an art­icle that has a strong warn­ing about pla­gi­ar­ism – Ed.]

Annals of Botany Office.

The Annals of Botany Office is based at the University of Leicester.