Sexual reproduction is a composite, not a singular, phenomenon and as such can be subdivided into a number of componentsi.e. fusion, recombination, fission, and the male-female phenomenon. These components can evolve independently, though any evolutionary change in one component is likely to influence the future evolution of the other components. The ambiguity that surrounds the term ‘sex’ due to a failure to recognise the composite nature of sexual reproduction has led to considerable confusion in past discussions of the evolution of (...) the phenomenon. This paper considers the possible chronological interaction of the components of sexual reproduction both with each other and with the sequence of selective pressures that seem likely to have acted. This chronological approach is used to consider: the origin of sexual reproduction; the evolution of sexual reproduction in the common ancestor of the procaryotes and eucaryotes; the modification of the ancestral system in the procaryote line following the procaryote-eucaryote dichotomy; and the modification of the ancestral system in the eucaryote line up to the origin of the male-female phenomenon.It is suggested that the fusion and recombination of the first living organisms were chronological continuations of the fusion and recombination of complex organic molecules that led up to the origin of life. The evolution of the third major component of sexual reproductioni.e. fission , by definition coincided with the origin of life. Initial selection on the components of sexual reproduction are likely to have been related to the optimum manifestations of size, complexity, diversity, multiplication, and distribution. Resultant early evolutionary trends are likely to have been: selective fusion between more-similar organisms; increase in number of fissions per fusion; and less recombination.The procaryote-eucaryote dichotomy is argued to have evolved in response to the increasing cellular problems of packing and replicating an increasing amount of hereditary material. The evolution of a single circular hereditary organelle in the procaryote line is argued to have led to the loss of total fusion and the specialisation of individuals into either donors or recipients. The donor-recipient phenomenon of procaryotes is directly analogous to the male-female phenomenon of eucaryotes and leads to parallel evolution due to sexual selection in both groups. In the eucaryote line the ancestral mechanism of sexual reproduction is argued to have persisted through, but to have been greatly modified by, the evolution of complex machinery for the handling of multiple hereditary organelles at cell division and reduction division. The evolutionary modification of the ancestral system of sexual reproduction is suggested to have led in eucaryotes to the evolution of: the species phenomenon; allelic recombination; and the male-female phenomenon. (shrink)

Really statistical explanation is a hitherto neglected form of noncausal scientific explanation. Explanations in population biology that appeal to drift are RS explanations. An RS explanation supplies a kind of understanding that a causal explanation of the same result cannot supply. Roughly speaking, an RS explanation shows the result to be mere statistical fallout.

We can understand viewed scenes and extract task-relevant information within a few hundred milliseconds. This process is generally supported by three cortical regions that show selectivity for scene images: parahippocampal place area (PPA), medial place area (MPA) and occipital place area (OPA). Prior studies have focused on the visual information each region is responsive to, usually within the context of recognition or navigation. Here, we move beyond these tasks to investigate gaze allocation during scene viewing. Eye movements rely on a (...) scene’s visual representation to direct saccades, and thus foveal vision. In particular, we focus on the contribution of OPA, which is i) located in occipito-parietal cortex, likely feeding information into parts of the dorsal pathway critical for eye movements, and ii) contains strong retinotopic representations of the contralateral visual field. Participants viewed scene images for 1034 ms while their eye movements were recorded. On half of the trials, a 500 ms train of five transcranial magnetic stimulation (TMS) pulses was applied to the participant’s cortex, starting at scene onset. TMS was applied to the right hemisphere over either OPA or the occipital face area (OFA), which also exhibits a contralateral visual field bias but shows selectivity for face stimuli. Participants generally made an overall left-to-right, top-to-bottom pattern of eye movements across all conditions. When TMS was applied to OPA, there was an increased saccade latency for eye movements toward the contralateral relative to the ipsilateral visual field after the final TMS pulse (400ms). Additionally, TMS to the OPA biased fixation positions away from the contralateral side of the scene compared to the control condition, while the OFA group showed no such effect. There was no effect on horizontal saccade amplitudes. These combined results suggest that OPA might serve to represent local scene information that can then be utilized by visuomotor control networks to guide gaze allocation in natural scenes. (shrink)

The often esoteric nature of dialogues about "consciousness" which take place in academic circles stands far removed from treatments of the same topic in lower division college classrooms. There, any detailed discussion of the various definitions which have been advanced for this term is likely to lead to frustration on the part of students who have not yet attained the requisite knowledge for appreciating this divergence of opinions. When teaching classes to introductory students, instructors can provide opportunities for students to (...) appreciate the diversity of their own experiences in addition to using more traditional pedagogic methods. In this paper, the author will describe several of the techniques which he has found useful in opening students up to the various panoramas within their minds. (shrink)

The Gateway to Inner Space: Sacred Plants, Mysticism and Psychotherapy. Festschrift in Honor of Albert Hofmann. edited by Christian Rätsch, Bridport and Dorset, England: Prism Press. 1989. 258 pp. ISBN 1‐85327‐037‐7. $10.95 (paper).

Prominent author and cultural critic Wendell Berry is well known for his contributions to agrarianism and environmentalism, but his commentary on education has received comparatively little attention. Berry has been eloquently unmasking America's cultural obsession with restless mobility for decades, arguing that it causes damage to both the land and the character of our communities. Education, he maintains, plays a central role in this obsession, inculcating in students' minds the American dream of moving up and moving on. Drawing on Berry's (...) essays, fiction, and poetry, Jack R. Baker and Jeffrey Bilbro illuminate the influential thinker's vision for higher education in this pathbreaking study. Each chapter begins with an examination of one of Berry's fictional narratives and then goes on to consider how the passage inspires new ways of thinking about the university's mission. Throughout, Baker and Bilbro argue that instead of training students to live in their careers, universities should educate students to inhabit and serve their places. The authors also offer practical suggestions for how students, teachers, and administrators might begin implementing these ideas. Baker and Bilbro conclude that institutions guided by Berry's vision might cultivate citizens who can begin the work of healing their communities -- graduates who have been educated for responsible membership in a family, a community, or a polity. (shrink)

The Nature of Shamanism: Substance and Function of. Religious Metaphor. Michael Ripinsky‐Naxon. Albany: State University of New York Press, 1993. xi. 289 pp. $19.95 (paper). $59.50 (cloth).

After summarizing my own views of 'I' and the first-person perspective, I consider a well-known autistic, Temple Grandin, who claims that she thinks only in pictures, not in language. I argue, to the contrary, that Grandin's mental life as she describes it in fact requires language, which, as a writer, she undoubtedly has. Finally, I turn to the question of whether thought as Temple Grandin describes it is independent of language.