Evolutionary connectionism: algorithmic principles underlying the evolution of biological organisation in evo-devo, evo-eco and evolutionary transitions

The mechanisms of variation, selection and inheritance, on which evolution by natural selection depends, are not fixed over evolutionary time. Current evolutionary biology is increasingly focussed on understanding how the evolution of developmental organisations modifies the distribution of phenotypic variation, the evolution of ecological relationships modifies the selective environment, and the evolution of reproductive relationships modifies the heritability of the evolutionary unit. The major transitions in evolution, in particular, involve radical changes in developmental, ecological and reproductive organisations that instantiate variation, selection and inheritance at a higher level of biological organisation. However, current evolutionary theory is poorly equipped to describe how these organisations change over evolutionary time and especially how that results in adaptive complexes at successive scales of organisation (the key problem is that evolution is self-referential, i.e. the products of evolution change the parameters of the evolutionary process). Here we first reinterpret the central open questions in these domains from a perspective that emphasises the common underlying themes. We then synthesise the findings from a developing body of work that is building a new theoretical approach to these questions by converting well-understood theory and results from models of cognitive learning. Specifically, connectionist models of memory and learning demonstrate how simple incremental mechanisms, adjusting the relationships between individually-simple components, can produce organisations that exhibit complex system-level behaviours and improve the adaptive capabilities of the system. We use the term “evolutionary connectionism” to recognise that, by functionally equivalent processes, natural selection acting on the relationships within and between evolutionary entities can result in organisations that produce complex system-level behaviours in evolutionary systems and modify the adaptive capabilities of natural selection over time. We review the evidence supporting the functional equivalences between the domains of learning and of evolution, and discuss the potential for this to resolve conceptual problems in our understanding of the evolution of developmental, ecological and reproductive organisations and, in particular, the major evolutionary transitions

Challenges to adaptation: a fundamental concept for the shared socio-economic pathways and beyond

The framework for the new scenarios being developed for climate research calls for the development of a set of Shared Socioeconomic Pathways (SSPs), which are meant to differ in terms of their challenges to mitigation and challenges to adaptation. In order for the scenario process to fulfill its goals, the research and policy communities need to develop a shared understanding of these concepts. This paper focuses on challenges to adaptation. We begin by situating this new concept in the context of the rich literatures related to inter alia adaptation, vulnerability, and resilience. We argue that a proper characterization of challenges to adaptation requires a rich, exploration of the concept, which goes beyond mere description. This has a number of implications for the operationalization of the concept in the basic and extended versions of the SSPs. First, the elements comprising challenges to adaptation must include a wide range of socioeconomic and even some (non-climatic) biophysical factors. Second, careful consideration must be given to differences in these factors across scales, as well as cross-scale interactions. Third, any representation of the concept will require both quantitative and qualitative elements. The scenario framework offers the opportunity for the SSPs and full scenarios to be of greater value than has been the case in past exercises to both Integrated Assessment Modeling (IAM) and Impacts,Adaptation, and Vulnerability (IAV) researchers, but this will require a renegotiation of the traditional, primarily unidirectional relationship between the two communities

Understanding multiple thresholds of coupled social–ecological systems exposed to natural hazards as external shocks

Societies and ecosystems worldwide are increasingly subjected to hazards of natural and anthropogenic origins. Increasing the resilience and reducing the vulnerability of social–ecological systems (SES) so that they can withstand these shocks is crucial. External shocks (e.g. cyclones, earthquakes, tsunamis, floods) can induce an SES to move from one regime to another (or one stability domain to another), the latter typically being unfavourable. This can be through the disruption of ecosystems and the services they provide to society and/or through disruption of the social and economic structure and networks of the SES. Important characteristics of SES are the thresholds (boundaries) separating stability domains, but these are very difficult to evaluate because of the complex nature of SES. We use the example of the 2004 Indian Ocean tsunami impact on groundwater resources and the coastal communities relying on them in Sri Lanka, to illustrate that a practical approach for SES threshold characterisation could be through description of the dependency of social groups with respect to essential ecosystem services and through an understanding of the state of the ecosystems providing these services. However, this is not sufficient and changes of adaptive capacities of different social groups, access to the environmental services and the interventions undertaken by different actors also need to be considered. Furthermore, the question of when (time and phase) and why (stimuli) SES might shift into another state should be reviewed more critically. The implication is that multiple thresholds within the sub-components of the SES have to be assessed