this paper, it is worth mentioning that, for orders of mollusks, echinoderms, mammals, and insects (with cumulative number of genera being used as a proxy for cumulative number of tries for mollusks and echinoderms, and cumulative number of families as such a proxy for mammals and insects), the rugged fitness landscapes model also does not hold, at least as far as the assumption of a single landscape is concerned (Eble 1995a). Deformation of landscapes with environmental change is a relevant issue here. It has been said that the ad hoc invocation of landscape deformation through time would render Kauffman's arguments essentially untestable (Levinton 1995). However, Kauffman (1993) implicitly assumes that deformation, even in the face of pronounced environmental perturbation, would be minor and not affect the general structure of the landscape at the higher taxonomic levels considered here. That the generation of morphological innovations in long-jump adaptation would be achieved by early ontogeny mutants lends support to claims for a relative stability of landscapes at higher levels, since the developmentally constrained set of possible changes at deeper levels of the hierarchy would be quite Gunther J. Eble 35 independent of environmental changes. Here is the irony of the rugged fitness landscapes model: by relying on ahistorical principles to explain history, historical effects must a priori be assumed to be largely ineffective; if history could change the nature of those ahistorical principles, then there would be nothing left to test. Landscapes in the present context would change only if fundamentally different genetic and morphogenetic controls were repeatedly appearing through time. This may well be the case in view of the present results, suggesting that histo...

We propose the use of formal ontological inferencing, rather than cladistics, to reconstruct phylogeny trees and to analyze the evolutionary relationships between species. For this experiment, we focused on the phylogeny of fungi. Lexical chaining technique has been used for incremental population of evolving ontological elements. Also category theory has been employed to provide an underlying formalism for capturing and analyzing the evolutionary behavior of the system.

Proceedings of a symposium entitled

In this response to Pinker and Jackendoff’s critique, we extend our previous framework for discussion of language evolution, clarifying certain distinctions and elaborating on a number of points. In the first half of the paper, we reiterate that profitable research into the biology and evolution of language requires fractionation of “language ” into component mechanisms and interfaces, a non-trivial endeavor whose results are unlikely to map onto traditional disciplinary boundaries. Our terminological distinction between FLN and FLB is intended to help clarify misunderstandings and aid interdisciplinary rapprochement. By blurring this distinction, Pinker and Jackendoff mischaracterize our hypothesis 3 which concerns only FLN, not “language ” as a whole. Many of their arguments and examples are thus irrelevant to this hypothesis. Their critique of the minimalist program is for the most part equally irrelevant, because very few of the arguments in our original paper were tied to this program; in an online appendix we detail the deep inaccuracies in their characterization of this program. Concerning evolution, we believe that Pinker and Jackendoff’s emphasis on the past adaptive history of the language faculty is misplaced. Such questions are unlikely to be resolved empirically due to a lack of relevant data, and invite speculation rather than research. Preoccupation with the issue has retarded progress in the field by diverting research away from empirical questions, many of which can be addressed with comparative data. Moreover, offering an adaptive hypothesis as an alternative to our hypothesis concerning mechanisms is a logical error, as questions of function are independent of those concerning mechanism. The second half of our paper consists of a detailed response to the specific data discussed by Pinker and Jackendoff. Although many of their examples are irrelevant to our original

ABSTRACT. The real number of variations is lesser than expected one. There are no blue-eyed Drosophila, no viviparous birds or turtles, no hexapod mammals, etc. Such observations provoke non-Darwinian evolutionary concepts. Darwin tried rather unsuccessfully to solve the problem of the contradictions between his model of random variability and the existence of constraints. He tried to hide this complication citing abundant facts on other phenomena. The authors of the modern versions of Darwinism followed this strategy, allowing the question to persist.

comparative methods; constraint; independent contrasts; natural selection; phylogenetic inertia; statistics. Before the Evolutionary Synthesis, ‘phylogenetic inertia ’ was associated with theories of orthogenesis, which claimed that organisms possessed an endogenous perfecting principle. The concept in the modern literature dates to Simpson (1944), who used ‘evolutionary inertia ’ as a description of pattern in the fossil record. Wilson (1975) used ‘phylogenetic inertia ’ to describe population-level or organismal properties that can affect the course of evolution in response to selection. Many current authors now view phylogenetic inertia as an alternative hypothesis to adaptation by natural selection when attempting to explain interspecific variation, covariation or lack thereof in phenotypic traits. Some phylogenetic comparative methods have been claimed to allow quantification and testing of phylogenetic inertia. Although some existing methods do allow valid tests of whether related species tend to resemble each other, which we term ‘phylogenetic signal’, this is simply pattern recognition and does not imply any underlying process. Moreover, comparative data sets generally do not include information that would allow rigorous inferences concerning causal processes underlying such patterns. The concept of phylogenetic inertia needs to be defined and studied with as much care as ‘adaptation’.

colour; crypsis; evolution; Gymnophiona; independent contrasts; pattern; selection. The proximate functions of animal skin colour are difficult to assign as they can result from natural selection, sexual selection or neutral evolution under genetic drift. Most often colour patterns are thought to signal visual stimuli; so, their presence in subterranean taxa is perplexing. We evaluate the adaptive nature of colour patterns in nearly a third of all known species of caecilians, an order of amphibians most of which live in tropical soils and leaf litter. We found that certain colour pattern elements in caecilians can be explained based on characteristics concerning above-ground movement. Our study implies that certain caecilian colour patterns have convergently evolved under selection and we hypothesize their function most likely to be a synergy of aposematism and crypsis, related to periods when individuals move overground. In a wider context, our results suggest that very little exposure to daylight is required to evolve and maintain a varied array of colour patterns in animal skin.

Abstract not found