Agency, teleonomy and signal transduction in plant systems

Plants are the basis of nearly all food chains. The evolutionary response to inevitable predatory and other contingent hazards has provided plants with remarkable regenerative and plastic capabilities. Teleonomy has been characterized as purposive, adaptive and goal-directed behaviour. The evidence that plants are agents, that they act purposefully, is indicated by numerous behaviours, most notably plasticity. Through recurrent information exchange, growing roots construct a dynamic niche with bacterial and fungal symbionts. Purposeful shoot plasticity enables adaptive responses to abiotic and biotic hazards, with the goal of survival. Transgenerational inheritance furthers that goal for sibling survival. Teleonomic goals in shoot growth use proprioception to ensure successful tropic responses. Unlike animals that acquire energy biotically, nearly all plants are dependent solely on the physical environment. Convergent evolution is common and may result from the constraints of unchanging physical laws. Phenotypic plasticity initially provides a direction for evolutionary change. Our article indicates that there are features to evolutionary change in plants additional to those indicated by the modern synthesis and thus supports the extended evolutionary hypothesis.