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

Computer Simulation on the Cooperation of Functional Molecules during the Early Stages of Evolution

It is very likely that life began with some RNA (or RNA-like) molecules, self-replicating by base-pairing and exhibiting enzyme-like functions that favored the self-replication. Different functional molecules may have emerged by favoring their own self-replication at different aspects. Then, a direct route towards complexity/efficiency may have been through the coexistence/cooperation of these molecules. However, the likelihood of this route remains quite unclear, especially because the molecules would be competing for limited common resources. By computer simulation using a Monte-Carlo model (with “micro-resolution” at the level of nucleotides and membrane components), we show that the coexistence/cooperation of these molecules can occur naturally, both in a naked form and in a protocell form. The results of the computer simulation also lead to quite a few deductions concerning the environment and history in the scenario. First, a naked stage (with functional molecules catalyzing template-replication and metabolism) may have occurred early in evolution but required high concentration and limited dispersal of the system (e.g., on some mineral surface); the emergence of protocells enabled a “habitat-shift” into bulk water. Second, the protocell stage started with a substage of “pseudo-protocells”, with functional molecules catalyzing template-replication and metabolism, but still missing the function involved in the synthesis of membrane components, the emergence of which would lead to a subsequent “true-protocell” substage. Third, the initial unstable membrane, composed of prebiotically available fatty acids, should have been superseded quite early by a more stable membrane (e.g., composed of phospholipids, like modern cells). Additionally, the membrane-takeover probably occurred at the transition of the two substages of the protocells. The scenario described in the present study should correspond to an episode in early evolution, after the emergence of single “genes”, but before the appearance of a “chromosome” with linked genes

About the neurolinguistics of the implicatures: abstract of a study

Taking into account recent data on linguistics of production and comprehension in aphasia, a protocol was executed including the several types of implicatures. The protocol was applied to 90 subjects classified according to the localization of cerebral lesions, as shown by CT. Results are discussed in report to clinical manifestations of brain lesions, as aphasia, apraxia, agnosia, and intelligence and pragmatics disturbances. Discussion supports the impression that there is a mechanism that correlates extra-linguistics contexts with the 'said' at the right hemisphere

Pontine tegmentum hematoma: a case report with the "one-and-a-half "syndrome without pyramidal tract deficit Hematoma tegmentar pontino: relato de caso com a síndrome "one-and-a-half" e sem déficit piramidal

The author reports the case of a 54-year-old male patient with a pontine hematoma and with the one-and-a-half syndrome, cerebellar ataxia and no signs of pyramidal tract involvement. The absence of involvement of the pyramidal tract in the case reported herein is likely due to variation in the vascular anatomy of the pons. The pathophysiologic mechanisms of the one-and-a-half syndrome and of the clinical findings recorded are discussed.<br>O autor relata o caso de um paciente de sexo masculino de 54 anos com hematoma pontino que se manifestou por síndrome "one-and-a-half" e ataxia cerebelar mas sem sinais de acometimento do trato piramidal. A ausência de acometimento do trato piramidal é decorrente possivelmente de uma variação da anatomia vascular do segmento pontino do tronco cerebral. Os achados clínicos do caso e os mecanismos fisiopatológicos da síndrome "one-and-a-half" são discutidos