Darwin, nós temos um problema - a teleonomia vai substituir a teleologia na biologia evolutiva?

Teleonomy: Revisiting a Proposed Conceptual Replacement for Teleology

Max Dresow & Alan C. Love 

Biological Theory (2023)

Abstract

The concept of teleonomy has been attracting renewed attention recently. This is based on the idea that teleonomy provides a useful conceptual replacement for teleology, and even that it constitutes an indispensable resource for thinking biologically about purposes. However, both these claims are open to question. We review the history of teleological thinking from Greek antiquity to the modern period to illuminate the tensions and ambiguities that emerged when forms of teleological reasoning interacted with major developments in biological thought. This sets the stage for an examination of Pittendrigh’s (Adaptation, natural selection, and behavior. In: Roe A, Simpson GG (eds) Behavior and evolution. Yale University Press, New Haven, pp 390–416, 1958) introduction of “teleonomy” and its early uptake in the work of prominent biologists. We then explore why teleonomy subsequently foundered and consider whether the term may yet have significance for discussions of goal-directedness in evolutionary biology and philosophy of science. This involves clarifying the relationship between teleonomy and teleological explanation, as well as asking how the concept of teleonomy impinges on research at the frontiers of evolutionary theory.

FREE PDF GRATIS: Biological Theory

Alô Academia Brasileira de Ciências: mais uma tempestade se aproxima na teoria da evolução.

An approaching storm in evolutionary theory 

Review of: Rereading Darwin’s Origin of Species: The Hesitations of an Evolutionist, by Richard G. Delisle and James Tierney,  2022.  Bloomsbury Academic, London. 176 pp. ISBN: 9781350259577

Alexander Czaja

Evolution, Volume 77, Issue 4, 1 April 2023, Pages 1170–1172, https://doi.org/10.1093/evolut/qpad009

Published: 26 January 2023

For about 10 years, something important has been brewing in the world of evolution, a great storm that, unfortunately, has so far only made itself felt among a few biologists, historians, and philosophers of biology and evolution (Jablonka & Lamb, 2005, 2020; Laland et al., 2014; Müller, 2017; Pigliucci & Müller, 2010; Skinner, 2015). Reading the work of most practicing biologists, one hardly sees any sign of this gathering storm. On the contrary, in standard textbooks and popular literature, no winds of resistance have been felt, and the ship known as the Modern Theory of Evolution (MTE) sails safely and undisturbed from its usual academic course. It remains to be seen how strong the storm will ultimately be.

One recent manifestation of this storm is the new book Rereading Darwin’s Origin of Species by Richard G. Delisle and James Tierney, a short read aimed at reaching a larger audience. Delisle is a paleoanthropologist who also holds a PhD in philosophy. His co-author, James Tierney, studied philosophy at the University of Chicago and is currently Director of the English Language Program at Yale University.

To get straight to the point: The book has no intention of capsizing the MTE ship or to unseating the modern theory but puts forth some provocative theses against the generally accepted view that Darwin was the first modern evolutionary thinker in history: the authors try to demonstrate that there is a wide gap between Darwin and evolutionists today. The most daring of their theses states that Darwin was not an evolutionist in the modern sense of the word. Indeed, the authors question the appropriation of Darwin by proponents of the MTE, who have always placed him and his Origin of Species at the conceptual center of their own model. The book provides compelling arguments that the MTE is based on a highly distorted and anachronistic picture of Darwin, both of his time and main work. Having set forth their case for a fresh look at the Origin, the authors delve deep and meticulously in Darwin’s main work, by uncovering its neglected ambiguities and contradictions. After years of collective Darwin euphoria, in which—as the authors self-critically note—they themselves actively participated, it is now time for a more critical approach. The authors call it “returning Darwin to the human dimension” (p. x) and they wonder “[w]hy has it taken so long for us to realize that Darwin’s commitment to evolutionism was incomplete?” (p. 6).

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Dicas químicas podem ter possibilitado o surgimento da multicelularidade

Chemical factors induce aggregative multicellularity in a close unicellular relative of animals

Núria Ros-Rocher, Ria Q. Kidner, Catherine Gerdt, +2, and Joseph P. Gerdt 

Authors Info & Affiliations

Edited by Joan Strassmann, Washington University in St. Louis, St. Louis, MO; received November 30, 2022; accepted February 14, 2023

April 24, 2023

120 (18) e2216668120

https://doi.org/10.1073/pnas.2216668120  

Image/Imagem

Significance

Whether the first multicellular animals utilized chemical cues to regulate cellular aggregation remains poorly studied. We discovered that aggregation of a unicellular close animal relative is induced by chemical cues, as observed in some animals and other unicellular species. This discovery expands the prevalence of chemically regulated multicellularity in unicellular animal relatives, which suggests that this trait may have been common in the close unicellular ancestors of animals. Our findings also yield a biochemical tool to further dissect the stages of aggregation in an emerging unicellular model and determine the extent of their homology to aggregation mechanisms in animals.

Abstract

Regulated cellular aggregation is an essential process for development and healing in many animal tissues. In some animals and a few distantly related unicellular species, cellular aggregation is regulated by diffusible chemical cues. However, it is unclear whether regulated cellular aggregation was part of the life cycles of the first multicellular animals and/or their unicellular ancestors. To fill this gap, we investigated the triggers of cellular aggregation in one of animals’ closest unicellular living relatives—the filasterean Capsaspora owczarzaki. We discovered that Capsaspora aggregation is induced by chemical cues, as observed in some of the earliest branching animals and other unicellular species. Specifically, we found that calcium ions and lipids present in lipoproteins function together to induce aggregation of viable Capsaspora cells. We also found that this multicellular stage is reversible as depletion of the cues triggers disaggregation, which can be overcome upon reinduction. Our finding demonstrates that chemically regulated aggregation is important across diverse members of the holozoan clade. Therefore, this phenotype was plausibly integral to the life cycles of the unicellular ancestors of animals.

FREE PDF GRATIS: PNAS Sup. Info.

Darwin, nós temos um problema: árvores evolutivas baseadas na anatomia podem estar erradas.

Molecular phylogenies map to biogeography better than morphological ones

Jack W. Oyston, Mark Wilkinson, Marcello Ruta & Matthew A. Wills 

Communications Biology volume 5, Article number: 521 (2022)

Image/Imagem: fabelacorrea / Adobe Sto

Abstract

Phylogenetic relationships are inferred principally from two classes of data: morphological and molecular. Currently, most phylogenies of extant taxa are inferred from molecules and when morphological and molecular trees conflict the latter are often preferred. Although supported by simulations, the superiority of molecular trees has rarely been assessed empirically. Here we test phylogenetic accuracy using two independent data sources: biogeographic distributions and fossil first occurrences. For 48 pairs of morphological and molecular trees we show that, on average, molecular trees provide a better fit to biogeographic data than their morphological counterparts and that biogeographic congruence increases over research time. We find no significant differences in stratigraphic congruence between morphological and molecular trees. These results have implications for understanding the distribution of homoplasy in morphological data sets, the utility of morphology as a test of molecular hypotheses and the implications of analysing fossil groups for which molecular data are unavailable.

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60 anos de silêncio revela insights em busca de vida extraterrestre.

Inferring the Rate of Technosignatures from 60 yr of Nondetection

Claudio Grimaldi1,2

Published 2023 April 13 • © 2023. The Author(s). Published by the American Astronomical Society.

The Astronomical Journal, Volume 165, Number 5

Citation Claudio Grimaldi 2023 AJ 165 199

DOI 10.3847/1538-3881/acc327

Image/Imagem: Deviant Art

Abstract

For about the last 60 yr the search for extraterrestrial intelligence has been monitoring the sky for evidence of remotely detectable technological life beyond Earth, with no positive results to date. While the lack of detection can be attributed to the highly incomplete sampling of the search space, technological emissions may be actually rare enough that we are living in a time when none cross the Earth. Here we explore the latter possibility and derive the likelihood of the Earth not being crossed by signals for at least the last 60 yr to infer upper bounds on their rate of emission. Under the assumption that technological emitters are distributed uniformly in the Milky Way and that they generate technoemissions at a constant rate, we find less than about one to five emissions generated per century with 95% credible level. This implies optimistic waiting times until the next crossing event of no less than 60–1800 yr with a 50% probability. A significant fraction of highly directional signals increases the emission rates' upper bounds, but without systematically changing the waiting time. Although these probabilistic bounds are derived from a specific model and their validity depends on the model's assumptions, they are nevertheless quite robust against weak time dependences of the emission rate or nonuniform spatial distributions of the emitters. Our results provide therefore a benchmark for assessing the lack of detection and may serve as a basis to form optimal strategies for the search for extraterrestrial intelligence.

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