Populations and Evolution (q-bio.PE)

Abstract: Models of invasive species spread often assume that landscapes are spatially homogeneous; thus simplifying analysis but potentially reducing accuracy. We extend a recently developed partial differential equation model for invasive conifer spread to account for spatial heterogeneity in parameter values and introduce a method to obtain key outputs (e.g. spread rates) from computational simulations. Simulations produce patterns of spatial spread remarkably similar to observed patterns in grassland ecosystems invaded by exotic conifers, validating our spatially explicit strategy. We find that incorporating spatial variation in different parameters does not significantly affect the evolution of invasions (which are characterised by a long quiescent period followed by rapid evolution towards to a constant rate of invasion) but that distributional assumptions can have a significant impact on the spread rate of invasions. Our work demonstrates that spatial variation in site-suitability or other parameters can have a significant impact on invasions

Abstract: The current theory of evolution is almost the one Darwin and Wallace proposed two centuries ago and the following discoveries e.g., Mendelian genetics and neutral mutation theory have not made significant modifications. The current evolution theory relies mostly on heritable variations within species population, natural selection and genetic drift. The inability of the current theory to explain and predict biological observations, especially the emergence of evolutionary novelties, highlights the need to incorporate recent evolutionary, developmental and genetics findings in order to achieve a more comprehensive explanation of species evolution. The present paper provides significant body of evidence to substantiate a new theory to account for species evolution. The main axes of the proposed theory include: First, mutations leading to genetic novelties in a given species during evolution should be guided by the environment surrounding that species. Second, environment and germline are connected with each other via soma-germline messengers e.g., non-coding RNAs (ncRNAs). Third, based on the information that germline continuously receives in terms of epigenetic messengers three stages of heritable changes may occur in germline genome to produce more adaptable offspring: i, Epigenetic modifications, ii, Genetic mutations in the sequence of pre-existing genes in order to improve their potency, and iii, The production of new genes with distinct gene-coding regions, which may have their own regulatory regions.