Do plants have a right to evolve? Odd question I know, and one that I would normally boot into touch by asking what the corresponding obligation might be. That discussion can keep a pub full of philosophers amused for days; for now, let’s stick to the claim, which seems to emerge from the recent burgeoning recognition that plants may be more sensitive than we have previously given them credit for. To me, sensitivity is a pretty poor basis for granting rights, but it seems to be enough for some people, not least Laura Jane Martin, blogging at Scientific American.
Her point is that, powerful though we may imagine ourselves to be, we cannot really halt evolution, and she wheels out the biggest gun of all, Charles Darwin himself, to make that point. Darwin used artificial selection as a familiar idea on which to build the more difficult case for natural selection. And he also didn’t think too much of the creations of artificial selection. Martin quotes this passage from The Origin:
How fleeting are the wishes and efforts of man! how short his time! and consequently how poor will be his results, compared with those accumulated by Nature during whole geological periods!
But that’s only half the story. Darwin immediately goes on to say:
Can we wonder, then, that Nature’s productions should be far “truer” in character than man’s productions; that they should be infinitely better adapted to the most complex conditions of life, and should plainly bear the stamp of far higher workmanship?
See, I happen to think that people have done a pretty good job of adapting plants and animals to “the most complex conditions of life”. Those conditions, however, weren’t changing all that quickly. Even when early farmers were moving across continents, I’m reasonably sure they weren’t getting into entirely unforeseen conditions every couple of generations. But with those first ventures into domestication and cultivation, people set themselves onto a path in which today, the entire global environment has changed. So is there a single species on Earth that hasn’t somehow had its right to evolve impinged upon by human activity? And doesn’t that make a bit of a mockery of the “right to evolve”? What about the rights of living things that have already been altered by people? Do they have any kind of right to continue being selected? Or do they maybe have a right to continue to be cultivated as they always were, so that their right to evolve to changing conditions is unfettered?
We are beginning to hear a version of the “right to evolve” argument even in agriculture, where something very similar is given as a reason for promoting on-farm conservation. I don’t like it any better in this form. Society as a whole may decide to pay farmers to conserve diversity, increasing its value to the point where a farmer can see the point of growing it. And those doing the paying may think that ongoing evolution is a good enough reason (among others) to hand over cash. But on its own it seems an awfully fragile foundation for such an important enterprise. And if it is that important, does it need this additional foundation?
As you can see I’m confused. Set me straight. Do plants have a “right to evolve”? And is “continuing evolution” a good enough reason for on-farm conservation?
Jeremy: As to your last point: does `continuing evolution’ on-farm imply getting better adapted varieties? At least for biotic constraints which reduce yield, probably not, as pests and diseases can evolve faster than varietal resistances. This may be the reason for farmers continually changing varieties, to bring in varieties from elsewhere not (at least initially) constrained by locally co-evolved pests and diseases. And also the reason why a large proportion of global crop (and pasture and managed forestry production) is from introduced species (with fewer associated pests and diseases).
Quantifying `continuing evolution’ of varieties on-farm could be a nightmare. Varieties could indeed evolve resistances but at the same time yield less and less. Varietal packages on-farm could maintain or, with the input of new varieties, increase yield, but lessening the chance of the evolution of resistances (needed by plant breeders). Farmers can fight yield loss by using mixtures and intercrops, at the same time reducing selective pressure for evolution to counter biotic constraints.
Also, for climate change, it could be better to bring in pre-adapted varieties from elsewhere rather than wait for local varieties to evolve (for which they may not have the required genetic diversity or, for most crops, outcrossing mechanisms to generate diversity).
Rather than conserving landraces in-situ it could stimulate evolution to introduce as much new varietal diversity as farmers can manage. The amount of seed, varieties, breeders’ lines thrown away by CGIAR institutes each year is a phenomenal waste of diversity.
Acknowledging and recognizing the rights of plants and animals is one of the pillars of the ‘Deep Ecology’ school of thought. I hardly see another mental construct that can explain the right for plants to evolve.
When Dave Wood writes the quantification of this evolution (showing proof that we actually are letting plants evolve ‘freely’) is going to be a nightmare, I understand his point. Nonetheless, I think the quantification of the ‘right to evolve’ is a non-issue: either you/your country’s ethical and moral prerogative lead you to believe plants must evolve freely without further human intervention, or it doesn’t lead you there.
To my eyes, the question of a plant’s right to evolve is indeed a philosophical/ethical one. Would recognizing this right help avoid overpopulation? No. Unless we are not allowed to kill a plant or animal…
The right of plants to evolve freely is somehow already respected when designing and establishing natural reserves. There maybe, plants can, to a certain extent, evolve freely, produce over a long time span useful varieties with agricultural potential. It makes no sense to apply the concept of ‘pure natural reserve’ to agricultural landscapes where ‘continuing evolution’ would take place.
As Jeremy writes, agricultural landscapes are man-made and man-controlled, and plants growing there are subjects of our activity and prospect.