Goodbye 'extinction,' hello 'evanescence'? Validating a new paradigm


Date:
June 18, 2020
Source:
University of Chicago Press Journals
Summary:
Naturalist and zoologist Georges Cuvier established extinction as
a distinct field of science in a series of publications beginning
in 1799.

He confirmed that fossil species were formerly living species
no longer extant, confirming similar conclusions of classical
Greek scholars.

However, mechanisms thought to control the process remained
controversial for two centuries.



FULL STORY ========================================================================== Naturalist and zoologist Georges Cuvier established extinction as a
distinct field of science in a series of publications beginning in
1799. He confirmed that fossil species were formerly living species
no longer extant, confirming similar conclusions of classical Greek
scholars. However, mechanisms thought to control the process remained controversial for two centuries.


==========================================================================
As Delbert Wiens, Timothy Sweet, and Thomas Worsley review in a new
article in The Quarterly Review of Biology (June 2020), biologists
did not become seriously interested in extinction until the mid-1980s,
when the field of conservation biology was founded in response to the
impending anthropogenic sixth mass extinction. Explanations for extinction
in the geological past have centered on speculation about cause, while neglecting effect. "Without a clear understanding of cause and effect,
it is impossible to establish a mechanism or to intervene successfully
in the process of an ongoing extinction event," they write.

In an earlier study, Wiens and co-author Thomas Worsley proposed "multigenerational, attritional loss of reproductive fitness," or MALF,
as a "complete" paradigm for extinction, which encompasses cause, effect,
and a mechanism of extinction. The new paper, "Validating the New Paradigm
for Extinction: Overcoming 200 Years of Historical Neglect, Philosophical Misconception, and Inadequate Language," verifies the paradigm.

To provide context for the new paradigm, the paper explores the
history of linguistic and philosophical contradiction or misconception concerning the term "extinction." As an example, as the authors note,
in the Christian era, only a supernatural agent was thought to possess
the power to extinguish a species.

The paper cites four independent tests of the new paradigm employing observational, experimental, and wholly theoretical techniques,
utilizing phyletically diverse organisms from disparate parts of the
Earth. The new paradigm was originally derived from studies of MALF on
six species of higher plants. The authors now report seven additional, worldwide examples.

The authors also discuss the inadequacy of "incomplete" paradigms
based largely on "cause-alone" explanations and consider logical inconsistencies and difficulties inherent in the usage of the term
"extinction" itself. "The assumption that background and mass extinction
are distinct processes introduces profound conceptual problems," they
note. "Descriptive, or nonconceptually based definitions are often
circular or meaningless, and must be distinguished from explicative definitions." Mass extinctions are categorized as "unusually large
extinction events," yet that "tell[s] us nothing about the characteristics
of these phenomena, which are the result of attempting to classify the
extremes of a continuum into distinctive categories." A step in the reconceptualization of extinction, the authors posit, is a new term for extinction. They propose "evanesce," inspired by Thomas Jefferson's use
of the term "evanish." "Evanescence" does not imply an external agent performing the action and fits the understanding of extinction as a
process without adding confusing connotations, they argue. "This process
may be a precursor or complement to evolution, but not necessarily so."
MALF (multigenerational, attritional loss of reproductive fitness) is
the causal mechanism by which the vast majority of species' extinctions ("evanescences") have occurred throughout biohistory. The incorporation
of MALF and "evanesce" into discussions of biohistory, the authors
argue, provide the means to determine the causal mechanisms necessary
for intervention, and the language to elaborate more fully the processes
of population decline and extinction.


========================================================================== Story Source: Materials provided by
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style and length.


========================================================================== Journal Reference:
1. Delbert Wiens, Timothy Sweet, Thomas Worsley. Validating the
New Paradigm
for Extinction: Overcoming 200 Years of Historical Neglect,
Philosophical Misconception, and Inadequate Language. The Quarterly
Review of Biology, 2020; 95 (2): 109 DOI: 10.1086/709086 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200618120159.htm

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