Biochemical controls: plant controls genetic or not (Introduction)

by David Turell , Friday, August 02, 2024, 18:33 (111 days ago) @ David Turell

Plants show purposeful actions, but how?:

https://aeon.co/essays/what-plant-philosophy-says-about-plant-agency-and-intelligence?u...

"Plant behaviour is, as the botanist Anthony Trewavas puts it, ‘what plants do’. It turns out that they do a lot. Take wounding. Most plants respond to damage to their leaves by releasing volatile organic compounds (VOCs). Some of these VOCs activate abiotic stress-related genes; some have antibacterial and antifungal properties. Some VOCs specifically repel the attacking herbivore with nasty tastes or toxins, and some plants can identify which specific herbivore is attacking, and produce different responses accordingly. Some VOCs attract the predators of the insects that are attacking the plant. Herbivore attack can also induce plants to produce more nectar, encouraging insects away from leaves.

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"...researchers found that plants grown in pots with kin plants grew more elongated stems with more branches, whereas those grown with non-kin grew more leaves, blocking other plants’ access to light. The plants thus seemed to cooperate with kin, whereas they tried to outcompete non-kin plants.

"... Many now believe that the results of this experimental work require us to acknowledge that plants enjoy properties and capacities previously thought to be exclusive to animals or even to humans. Some think that we simply cannot understand what the science is showing us without recourse to these terms.

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"The redefinition of some terms more usually associated with philosophy than with the sciences – terms like ‘intentionality’, ‘action’ and ‘purpose’ – is already underway in the interpretations of plant behaviour according to the new paradigm. The idea of plant intelligence is central to this. If we begin with the presumption that ‘intelligence’ is an exclusive feature of animal behaviour and that it requires a brain and a central nervous system, or that it is a kind a quantifiable property or capacity of organisms with brains and central nervous systems, then of course we will dismiss the idea of plant intelligence. Advocates of plant intelligence are on strong ground, though, in denying that that presumption has any warrant.

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"...it makes sense to describe plant behaviour as intelligent. It makes sense further to specify the definition for plants. Trewavas accordingly defines plant intelligence as ‘adaptively variable behaviour during the lifetime of the individual’. Examples of this adaptively variable behaviour in plants include directional root growth towards water sources, phototropism (the orientation of a plant towards light) and the release of volatile chemicals as a response to herbivore attack.

"...Intelligence according to this definition is thus an intrinsic feature of organisms capable of survival...At issue would be the definition of intelligence itself, which is a philosophical question: what is intelligence? There is an inescapably philosophical dimension underlying the novel paradigm in the plant sciences. Philosophy is baked into this kind of plant science.

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"What is it to be an agent? What does it mean to have agency? Do plants have agency in the same way as animals or more particularly humans? Gilroy and Trewavas describe plants as agents that ‘act autonomously to direct their own behaviour to achieve both external and internal goals or norms … while in continuous long-term interaction with the real-world environment.’

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"The philosopher of biology Samir Okasha makes a useful distinction between what he calls the ‘organisms-as-agents’ thesis and the ‘organism-as-agent’ heuristic. The first makes an ontological claim about what kinds of things organisms are; Okasha associates this with the opposition to the gene-centric paradigm in biology. The ‘organism-as-agent’ heuristic, on the other hand, is a pragmatic approach that, for the purposes of scientific understanding, treats organisms as if they were agents with goals.

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"Sultan also writes that agency ‘is an empirical property’ of biological systems, ‘a distinctive feature of organisms, the capacity of their constituent systems to respond adaptively to their circumstances’. The agency perspective ‘begins with the observation that organism are agents’ and recognising this helps us to understand how they develop, function and evolve.

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"‘Agency’ is essentially a term that shifts attention from genes to active response mechanisms, mechanisms leading to changes in development that are in some cases heritable. The ‘agency perspective’ can thus be understood as the name for a research programme that complements gene-focused approaches and not necessarily the attribution of a special capacity to plants. Further, Sultan – like almost all philosophers of biology – explicitly denies that the agency perspective implies in the plant any ‘intention’ to act, much less any conscious intention.

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Comment: down to basics, we know how information-rich a zygote is about to produce a full-grown fetus from its combined DNA. The discussion here is behavior, gene-centered or not? Agency may simply be a gene-directed reaction. If DNA can direct embryologic production, why can't it be seen as controlling behaviors, which require less information?