International Society for History, Philosophy, and Social Studies of Biology


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Program

MONDAY, JULY 6  /  11:00 - 12:30  /  DS-R340
Individual papers
Species Questions: Missing Links, New Concepts, and Metaphysics

Hypothetical common ancestors and the search for missing links

Richard Javier Stephenson (University of Cincinnati, United States)

In trying to reconstruct the evolutionary history of life, biologists and paleontologists often come across many instances of missing links. The characteristics of these ancestral forms is important for understanding the history of taxa and the attributes of descendent organisms. However, hypothesis about the characteristics these common ancestors can be problematic if these ancestors are interpreted as descriptions of some potential actual organism. Lindberg and Ghiselin demonstrated this issue in 2003 with their evaluation of the hypothetical ancestral mollusc or HAM. This paper looks to expand Lindberg and Ghiselin’s criticisms of the HAM to issues in regards to the use hypothetical common ancestors in finding actual common ancestors in the fossil and genetic records. It will focus on the assumptions made for such projects, and bring to question what role if any hypothetical ancestors play in the investigation of missing links and transitional forms.


The mechanism of neo-biological species concept: From reproductive isolation to communicative isolation

Bo-Chi G. Lai (Da-Yeh University, Taiwan)

The debates of different species concepts proposed by the major biological scholars in 2000 have been regarded as the modern species concepts formed. In the debates, the biological species concept (BSC) proposed by Ernst Mayr was one of popular species concepts in decades. In Species Concepts and Phylogenetic Theory (2000), there are important debates among 4 major species concepts: “The Biological Species Concept”, “The Hennigian Species Concept”, “The Phylogenetic Species Concept” and “The Evolutionary Species Concept”. Ernst Mayr not only modify the BSC to more molecular evolutionary theories and phylogenetic concerns but also defense that the BSC is the only concept can illustrate the meanings of species referring to both species as taxa and the category species. The mechanism of BSC concept is based on “reproductive isolation”: members of biological species are united by being reproductively compatible and at least potentially. However, there are several critiques on the BSC, such as the concept of species will be limited in because the reproductive isolation mechanism will fail to identify species in evolutionary process. The communicative isolation mechanism, the basis of Neo-Biological Species Concept (Neo-BSC), is modified from the idea of reproductive isolation. The communication is grounded on the successful response to the signal between individuals, and the signal is in a broad meaning from gene level to individual level. The mechanism will not only try to answer the critiques but also to solve the problem of applying the Neo-BSC on the asexually reproductive organisms. Just as Mayrs claimed, “... since this is often misunderstood, that species taxa are multidimensional, but the nondimensional situation is required to determine the crucial biological properties of the species concept”, my work is trying to continue to develop the BSC consummately.


The relevance of the metaphysics of time and temporal persistence for the species problem and the organism problem

August Martin (Universiteit Leiden, Netherlands)

I argue in favor of the view that biological entities occupying distinct levels of biological organization can exhibit distinct modes of temporal persistence. I call this the “disparate persistence” (DP) thesis. Its relevance becomes apparent when considering implications of the organism problem and the species problem. The “species problem” (Richards 2010) is propelled by disagreements over the metaphysical status of species, and whether species are sets, kinds, or individuals. The “organism problem” (Pepper and Herron 2008), part of the problem of biological individuality (J. Wilson 1999; Clarke 2010), is propelled by disagreements over resolutions to unclear cases of biological entities that exhibit poor integration and unclear boundaries. I will show how these problems are related. Pluralistic accounts (J. Wilson 1999) advance multiple kinds of biological individuals, each potentially requiring a species concept, and so necessitating species pluralism. Furthermore, species concepts and organism concepts harbor underlying assumptions about the temporal persistence of species and organisms. Crane (2004) and Reydon (2004, 2008) demonstrate that different species concepts imply different models of temporal persistence. Some species concepts model species as 4D perduring objects, while other species concepts model species as 3D enduring objects. Importantly, Hull (1989) argues that 4D perduring objects must have perduring parts; therefore, the organisms of 4D perduring species must also be 4D perduring objects. Organism concepts and concepts of biological individuals themselves entail endurantism or perdurantism. A resolution to the organism problem that necessitates 3D enduring organisms, given Hull’s claim, would lead to the unwelcome imposition that a resolution to the species problem would be restricted to 3D endurantist species concepts. The DP thesis dissolves this tension by allowing species and organisms to exhibit distinct modes of temporal persistence.