The Bretskyan hierarchy, multiscale allopatry, and geobiomes—on the nature of evolutionary things

Abstract

The process of evolution and the structures it produces are best understood in the light of hierarchy theory. The biota traditionally is described by either the genealogical Linnaean hierarchy or economic hierarchies of communities or ecosystems. Here we describe the Bretskyan hierarchy—a hybrid eco-genealogical hierarchy that consists of nested sets of different-sized, usually polyphyletic communities of interacting individuals separated from other such communities in space and time at multiple scales. The Bretskyan hierarchy consists of elements that have both genealogical and economic properties and functions—situated between, and connecting the elements of, the economic hierarchies (Vernadskyan) and the genealogical (Linnaean) hierarchy. The described hierarchy at lower tiers is populated by holobionts, individuals composed of multiple polyphyletic lineages integrated by functional interactions or biotically fabricated structures, such as membranes. At larger spatial tiers and longer time scales, the members of the Bretskyan hierarchy are of a more diffuse nature, partially due to the small size and relatively short duration of us as observers of larger and longer-lasting structures, here described as geobiomes. Their individuality is externally forced and directly tied to the spatial and temporal physical structures of our planet. These are sub-bioprovinces and bioprovinces—large and effectively isolated spatiotemporal structures of biota integrated internally by coevolution and individuated externally by a hierarchy of barriers. Gaia is here understood as the largest eco-genealogical individual compartmentalized by the outer space of the Earth and integrated at long time scales by biotic interactions and plate tectonic mixing of biota. The existence of a hierarchy of barriers and multilevel allopatry suggests that geographic isolation takes part not only in individuating species lineages, but also in producing coherent complexes of separate lineages forming bioprovinces at multiple space and time scales. The sizes, configurations, and durations of Bretskyan units are directly tied to geodynamics, demonstrating the central role of the physical planet in the processes of individuation and merging of geobiomes and the control of coevolution, and all its ramifications, at multiple space and time scales. The Bretskyan hierarchy also allows the integration of previously unconnected themes—“egalitarian” major transitions in individuality (e.g., eukaryogenesis) and some of the megatrajectories in the history of life—into a single theoretical framework of spatial and temporal scaling of eco-genealogy. The pervasive scaling of geodynamical processes and the direct connection of geodynamics to the dynamics of Bretskyan units allows us to formulate conjectures on the scales and limits of spatial and temporal contingency and competitiveness of biotas in evolution.

hespdiv: an R package for spatially constrained, hierarchical and contiguous regionalization in palaeobiogeography

“…The proposed method also includes means to evaluate the reliability of bioregionalizations obtained and is grounded in an informative and realistic perspective of bioregions. We will explicitly define this perspective here and it is discussed in greater detail in Spiridonov & Eldredge (2024).…”

“…The only hierarchy known to us that combines genealogical information and ecological functioning of biotic entities is the Bretskyan hierarchy (Spiridonov & Eldredge 2024). Thus, an interpretation of bioregions obtained using hespdiv is based on the notion of the recently revised Bretskyan hierarchy of eco-genealogical entities (Eldredge 1985;Knox 1998;Spiridonov & Eldredge 2024); this is a hierarchy of species communities which are tied together by geological barriers and ecological interactions (population interactions, as well as energy and matter transfer), which also share common evolution in the same place, thus forming co-genealogy due to spatial and temporal proximity and higher likelihood of all kinds of interactions inside these contiguous biotic units recently called geobiomes (Spiridonov & Eldredge 2024). As a result of geological processes, such as tectonics or climate change, and also due to biological evolution of dispersal and species range shifts, the boundaries of bioregions can split, and fuse at all spatial and temporal scales.…”

“…As a result of geological processes, such as tectonics or climate change, and also due to biological evolution of dispersal and species range shifts, the boundaries of bioregions can split, and fuse at all spatial and temporal scales. Here, geobiomes or bioregions, terms applicable for biotic configurations at any spatial scale, are seen as ontological individuals (for discussion of biological individuality see : Eldredge 1989;Gould 2002) or fuzzybounded individual-like entities (for discussion of species as an individual case see Rieppel 2007), with their times of origin, persistence, and disappearance by means of extinction, fusion with other bioregions, or fission into smaller bioregions (Spiridonov & Eldredge 2024). Also, bioregions in the Bretskyan hierarchy of eco-genealogical entities, as for example taxa in the Linnaean hierarchy, form larger bioregions at a higher hierarchical level.…”

“…) due to its hybrid nature and the difficulties in operationally defining the boundaries of its constituents. On the other hand, we now have a much clearer understanding of the nature of geobiomes, which are spatially contiguous biotic entities separated from other such entities by space and abiotic barriers (Spiridonov & Eldredge 2024). The dynamics of geobiomes ultimately modulate co-evolution and coordination of biotas at all spatial and temporal scales (Spiridonov & Eldredge 2024), and thus to a significant degree control the pace and coherence of macroevolution at the global scale .…”

“…On the other hand, we now have a much clearer understanding of the nature of geobiomes, which are spatially contiguous biotic entities separated from other such entities by space and abiotic barriers (Spiridonov & Eldredge 2024). The dynamics of geobiomes ultimately modulate co-evolution and coordination of biotas at all spatial and temporal scales (Spiridonov & Eldredge 2024), and thus to a significant degree control the pace and coherence of macroevolution at the global scale . Therefore, the emergence of new spatially contiguous hierarchical clustering methods will enable us to empirically reveal the explicit multilevel spatial structure of geobiomes (including the uncertainties of this structure), while acknowledging and preserving during the analysis their individual-like ontological properties, at all spatial and time scales.…”