scholarly journals The living fossil concept: reply to Turner

2021 ◽  
Vol 36 (2) ◽  
Author(s):  
Scott Lidgard ◽  
Alan C. Love
Keyword(s):  
Complex Problem ◽  
Morphological Stability ◽  
Main Argument ◽  
Geological Time ◽  
Problem Space ◽  
Living Fossil ◽  
Living Fossils ◽  
Tadpole Shrimps ◽  
Evolutionary Stasis

AbstractDespite the iconic roles of coelacanths, cycads, tadpole shrimps, and tuataras as taxa that demonstrate a pattern of morphological stability over geological time, their status as living fossils is contested. We responded to these controversies with a recommendation to rethink the function of the living fossil concept (Lidgard and Love in Bioscience 68:760–770, 2018). Concepts in science do useful work beyond categorizing particular items and we argued that the diverse and sometimes conflicting criteria associated with categorizing items as living fossils represent a complex problem space associated with answering a range of questions related to prolonged evolutionary stasis. Turner (Biol Philos 34:23, 2019) defends the living concept against a variety of recent skeptics, but his criticism of our approach relies on a misreading of our main argument. This misreading is instructive because it brings into view the value of three central themes for rethinking the living fossil concept—the function of concepts in biology outside of categorization, the methodological importance of distinguishing parts and wholes in conceptualizing evolutionary phenomena, and articulating diverse explanatory goals associated with these phenomena.

Problem Orientation

2018 ◽  
pp. 138-156
Author(s):  
Paul Battersby
Keyword(s):  
Complex Problem ◽  
Dynamic Mode ◽  
Global Approach ◽  
Complex Dynamic ◽  
Problem Space ◽  
Thick Description ◽  
Global Response ◽  
Problem Orientation ◽  
New Knowledge ◽  
Creative Problem

Globalization is complex, dynamic, and unpredictable. A commensurably dynamic mode of analysis is thus required for the necessary task of comprehending globalization’s intricacies and consequences. Adopting a creative, problem-based technique, this chapter develops a global approach to problem orientation. Irregular migration is the topic focus used to map out how a complex problem space can be constructed and how notions of complexity can be imaginatively applied to explore avenues for global response. A global problem orientation accepts that new knowledge can form at the interstices of different systems or schools of thought. The creative–imaginative technique discussed in this chapter encourages the use of divergent models or paradigms in tandem to enable thick description and deep analysis of complex problem spaces.

scholarly journals When Complexity Is Your Friend: Modeling the Complex Problem Space of Vocabulary

2018 ◽  
Vol 8 (4) ◽  
pp. 169 ◽  
Author(s):  
Amanda Goodwin ◽  
Yaacov Petscher ◽  
Dan Reynolds ◽  
Tess Lantos ◽  
Sara Gould ◽  
...  
Keyword(s):  
Complex Problem ◽  
Vocabulary Knowledge ◽  
Research Assessment ◽  
Word Knowledge ◽  
Problem Space ◽  
Confirmatory Factor ◽  
History Of ◽  
Standardized Measure ◽  
Theory Research ◽  
Vocabulary Assessment

The history of vocabulary research has specified a rich and complex construct, resulting in calls for vocabulary research, assessment, and instruction to take into account the complex problem space of vocabulary. At the intersection of vocabulary theory and assessment modeling, this paper suggests a suite of modeling techniques that model the complex structures present in vocabulary data in ways that can build an understanding of vocabulary development and its links to instruction. In particular, we highlight models that can help researchers and practitioners identify and understand construct-relevant and construct-irrelevant aspects of assessing vocabulary knowledge. Drawing on examples from recent research and from our own three-year project to develop a standardized measure of language and vocabulary, we present four types of confirmatory factor analysis (CFA) models: single-factor, correlated-traits, bi-factor, and tri-factor models. We highlight how each of these approaches offers particular insights into the complex problem space of assessing vocabulary in ways that can inform vocabulary assessment, theory, research, and instruction. Examples include identifying construct-relevant general or specific factors like skills or different aspects of word knowledge that could link to instruction while at the same time preventing an overly-narrow focus on construct-irrelevant factors like task-specific or word-specific demands. Implications for theory, research, and practice are discussed.

Ontogenetic sequence comparison of extant and fossil tadpole shrimps: no support for the “living fossil” concept

PalZ ◽  
2017 ◽  
Vol 91 (4) ◽  
pp. 463-472 ◽  
Author(s):  
Philipp Wagner ◽  
Joachim T. Haug ◽  
Jürgen Sell ◽  
Carolin Haug
Keyword(s):  
Sequence Comparison ◽  
Living Fossil ◽  
Tadpole Shrimps

scholarly journals Resequencing 545 ginkgo genomes across the world reveals the evolutionary history of the living fossil

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yun-Peng Zhao ◽  
Guangyi Fan ◽  
Ping-Ping Yin ◽  
Shuai Sun ◽  
Ning Li ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Charles Darwin ◽  
Eastern China ◽  
Population Expansion ◽  
Fossil Species ◽  
Living Fossil ◽  
Living Fossils ◽  
Bioclimatic Variables ◽  
The World ◽  
History Of

Abstract As Charles Darwin anticipated, living fossils provide excellent opportunities to study evolutionary questions related to extinction, competition, and adaptation. Ginkgo (Ginkgo biloba L.) is one of the oldest living plants and a fascinating example of how people have saved a species from extinction and assisted its resurgence. By resequencing 545 genomes of ginkgo trees sampled from 51 populations across the world, we identify three refugia in China and detect multiple cycles of population expansion and reduction along with glacial admixture between relict populations in the southwestern and southern refugia. We demonstrate multiple anthropogenic introductions of ginkgo from eastern China into different continents. Further analyses reveal bioclimatic variables that have affected the geographic distribution of ginkgo and the role of natural selection in ginkgo’s adaptation and resilience. These investigations provide insights into the evolutionary history of ginkgo trees and valuable genomic resources for further addressing various questions involving living fossil species.

Are wounded-tree beetles living fossils? A new nosodendrid genus from Burmese amber with bilobed tarsi (Coleoptera: Nosodendridae)

2021 ◽  
Vol 4 (1) ◽  
pp. 050-056
Author(s):  
ERIK TIHELKA ◽  
YAN-DA LI ◽  
DI-YING HUANG ◽  
CHEN-YANG CAI
Keyword(s):  
New Genus ◽  
Unique Feature ◽  
Body Plan ◽  
Compound Eyes ◽  
Living Fossil ◽  
Burmese Amber ◽  
Climbing Plants ◽  
Living Fossils ◽  
Geological Past

Nosodendridae, the wounded-tree beetles, are a small polyphagan family with less than 100 described species placed into two extant and one fossil genera. Here we describe a new nosodendrid genus and species, Mesonosa scandens gen. et sp. nov., from mid-Cretaceous Burmese amber from northern Myanmar (ca. 99 Ma). The new genus differs from extant nosodendrids in its bilobed tarsomeres 2–4, as well as putatively plesiomorphic characters such as strongly protuberant compound eyes and relatively elongate prosternum. The distinctly lobed tarsi are a unique feature within Nosodendridae, and likely represent an adaptation for climbing plants. The discovery of a third wounded-tree beetle genus from the Mesozoic indicates that while their body plan remained relatively conserved since the Cretaceous, nosodendrids have been more ecomorphologically diverse in the geological past than the present day, and thus are an example of a true “living fossil” lineage.

Structure and habits of living branchiopod crustaceans and their bearing on the interpretation of fossil forms

1985 ◽  
Vol 76 (2-3) ◽  
pp. 103-113 ◽  
Author(s):  
Geoffrey Fryer
Keyword(s):  
Recent Work ◽  
Adaptive Radiation ◽  
Living Animal ◽  
Genomic Evolution ◽  
Living Fossil ◽  
Larval Stages ◽  
Living Fossils ◽  
Morphological Stasis

ABSTRACTBranchiopods are primitive crustaceans whose history extends back at least to the Devonian, yet some are highly successful today. Most fossil branchiopods do not show many features that lead to an understanding of function, but the Devonian lipostracan Lepidocaris is an exception. Recent work on living branchiopods, especially anostracans and anomopod cladocerans, enables Lepidocaris to be considered as a living animal. Work on extant anostracan nauplii also makes it possible to deduce how its larval stages swam and collected food.Other early crustaceans are briefly considered and comments are made on the concept of “living fossils”. While rates of morphological and genomic evolution are often discordant, the concept is still useful. Some branchiopods, such as the Notostraca, display remarkable morphological stasis: on the basis of morphology, a Triassic and a present-day form appear to be conspecific. The latter may be referred to as a “living fossil”.The outstanding morphological stasis of the crustacean nauplius is noted. Its existence in Cambrian times, deducible from its distribution among modern taxa, has been confirmed by Müller's finds. Such stasis, involving part of the genome of organisms whose adults display enormous adaptive radiation, has persisted with relatively small modifications since before the commencement of the entire radiation of vertebrates.

scholarly journals DESIGNING IN COMPLEXITY: HOW SOLUTION CONJECTURES INFORM PROBLEM EXPLORATION

2021 ◽  
Vol 1 ◽  
pp. 1153-1162
Author(s):  
Wenlin Zhang ◽  
Jin Ma
Keyword(s):  
Design Theory ◽  
Process Model ◽  
Complex Problem ◽  
Design Practice ◽  
Problem Space ◽  
Design Problems ◽  
Problem Situations ◽  
Dynamic View ◽  
Three Phase ◽  
Space Expansion

AbstractEngineering designers seek to explore ‘real’ problems that must be solved across design processes. This exploration might be challenging in complex problem situations. An effective way of encouraging design exploration is conjecture-based problem exploration—informing problem re-interpretation by potential solutions. However, little evidence indicated how this process unfolds, especially in complex problem situations. This study addresses this question by articulating the underlying cognitive mechanism of conjecture-based problem exploration. Situated in a creative design practice that tackles real-world, complex problem situations, we employ grounded theory to conduct qualitative coding of interview transcripts and documents elicited from ten multidisciplinary graduate students. We developed a three-phase process model to explain conjecture-based problem exploration: (1) triggering through analogizing, inspiring, evaluating, and questioning; (2) transitioning to problem space expansion; and (3) resulting in problem focus adjustment incrementally or radically. Our explanation contributes to design theory building and encourages engineering designers to embrace a dynamic view of design problems when addressing complexity.

scholarly journals Machine learning models of problem space navigation: The influence of gender

2005 ◽  
Vol 2 (2) ◽  
pp. 83-98 ◽  
Author(s):  
Ron Stevens ◽  
Amy Soller
Keyword(s):  
Gender Differences ◽  
Problem Solving ◽  
Complex Problem ◽  
Markov Modeling ◽  
Complex Problem Solving ◽  
Problem Space ◽  
Space Navigation ◽  
Hidden Markov Modeling ◽  
Problem Solving Strategy ◽  
Solving Strategy

We have developed models of how problem spaces are navigated as male and female secondary school, university, and medical students engage in repetitive complex problem solving. The strategies that students used when solving problem-solving simulations were first classified with self-organizing artificial neural networks resulting in problem solving strategy maps. Next, learning trajectories were developed from sequences of performances by Hidden Markov Modeling that stochastically described students' progress in understanding different domains. Across middle school to medical school there were few gender differences in the proportion of cases solved; however, six of the seven problem sets showed significant gender differences in both the strategies used (ANN classifications) as well as the in the HMM models of progress. These results were extended through a detailed analysis of one problem set. For this high school / university problem set, gender differences were seen in how the problems were encoded consolidated and retrieved. These studies suggest that strategic problem solving differences are common across gender, and would be masked by simply looking at the outcome of the problem solving event.

scholarly journals The first late cretaceous mawsoniid coelacanth (Sarcopterygii: Actinistia) from North America: Evidence of a lineage of extinct ‘living fossils’

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259292
Author(s):  
Lionel Cavin ◽  
Pablo Toriño ◽  
Nathan Van Vranken ◽  
Bradley Carter ◽  
Michael J. Polcyn ◽  
...  
Keyword(s):  
North America ◽  
Eastern Coast ◽  
Time Duration ◽  
Living Fossil ◽  
Living Fossils ◽  
Life Traits ◽  
Slow Evolution ◽  
Vertebrate Assemblage ◽  
Fossil Records ◽  
The Impact

Today, the only living genus of coelacanth, Latimeria is represented by two species along the eastern coast of Africa and in Indonesia. This sarcopterygian fish is nicknamed a "living fossil", in particular because of its slow evolution. The large geographical distribution of Latimeria may be a reason for the great resilience to extinction of this lineage, but the lack of fossil records for this genus prevents us from testing this hypothesis. Here we describe isolated bones (right angular, incomplete basisphenoid, fragments of parasphenoid and pterygoid) found in the Cenomanian Woodbine Formation in northeast Texas that are referred to the mawsoniid coelacanth Mawsonia sp. In order to assess the impact of this discovery on the alleged characteristic of "living fossils" in general and of coelacanths in particular: 1) we compared the average time duration of genera of ray-finned fish and coelacanth in the fossil record; 2) we compared the biogeographic signal from Mawsonia with the signal from the rest of the vertebrate assemblage of the Woodbine formation; and 3) we compared these life traits with those of Latimeria. The stratigraphical range of Mawsonia is at least 50 million years. Since Mawsonia was a fresh, brackish water fish with probably a low ability to cross large sea barriers and because most of the continental components of the Woodbine Fm vertebrate assemblage exhibit Laurasian affinities, it is proposed that the Mawsonia’s occurrence in North America is more likely the result of a vicariant event linked to the break-up of Pangea rather than the result of a dispersal from Gondwana. The link between a wide geographic distribution and the resilience to extinction demonstrated here for Mawsonia is a clue that a similar situation existed for Latimeria, which allowed this genus to live for tens of millions of years.

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