arXiv subjects

E. Brigatti

Publications and source records attributed to E. Brigatti.

22 records · Page 2Linked to original sources

arXiv2007

Speciational view of macroevolution: are micro and macroevolution decoupled?

We introduce a simple computational model that, with a microscopic dynamics driven by natural selection and mutation alone, allows the description of true speciation events. A statistical analysis of the so generated evolutionary tree captures realistic features showing power laws for frequency distributions in time and size. Albeit these successful predictions, the difficulty in obtaining punctuated dynamics with mass extinctions suggests the necessity of decoupling micro and macro-evolutionary mechanisms in agreement with some ideas of Gould's and Eldredge's theory of punctuated equilibrium.

q-bio.PE↗

arXiv2006

Evolution of polymorphism and sympatric speciation through competition in a unimodal distribution of resources

A microscopic agent dynamical model for diploid age-structured populations is used to study evolution of polymorphism and sympatric speciation. The underlying ecology is represented by a unimodal distribution of resources of some width. Competition among individuals is also described by a similar distribution, and its strength is maximum for individuals with the same phenotype and decreases with distance in phenotype space as a gaussian, with some width. These two widths define the model's phase space, in which we identify the regions where an autonomous emergence of stable polymorphism or speciation is more likely.

q-bio.PE↗

arXiv2005

Sharp gene pool transition in a population affected by phenotype-based selective hunting

We use a microscopic model of population dynamics, a modified version of the well known Penna model, to study some aspects of microevolution. This research is motivated by recent reports on the effect of selective hunting on the gene pool of bighorn sheep living in the Ram Mountain region, in Canada. Our model finds a sharp transition in the structure of the gene pool as some threshold for the number of animals hunted is reached.

q-bio.PE↗

arXiv2005

Scaling properties of the Penna model

We investigate the scaling properties of the Penna model, which has become a popular tool for the study of population dynamics and evolutionary problems in recent years. We find that the model generates a normalised age distribution for which a simple scaling rule is proposed, that is able to reproduce qualitative features for all genome sizes.

q-bio.PE↗