scholarly journals Developmental influence on evolutionary rates and the origin of placental mammal tooth complexity

2021 ◽  
Vol 118 (23) ◽  
pp. e2019294118
Author(s):  
Aidan M. C. Couzens ◽  
Karen E. Sears ◽  
Martin Rücklin
Keyword(s):  
Computational Model ◽  
Adaptive Radiation ◽  
Growth Pattern ◽  
Self Regulation ◽  
Evolutionary Rates ◽  
Morphological Adaptation ◽  
Dental Evolution ◽  
Bud Growth ◽  
Enamel Knots ◽  
Upper Molar

Development has often been viewed as a constraining force on morphological adaptation, but its precise influence, especially on evolutionary rates, is poorly understood. Placental mammals provide a classic example of adaptive radiation, but the debate around rate and drivers of early placental evolution remains contentious. A hallmark of early dental evolution in many placental lineages was a transition from a triangular upper molar to a more complex upper molar with a rectangular cusp pattern better specialized for crushing. To examine how development influenced this transition, we simulated dental evolution on “landscapes” built from different parameters of a computational model of tooth morphogenesis. Among the parameters examined, we find that increases in the number of enamel knots, the developmental precursors of the tooth cusps, were primarily influenced by increased self-regulation of the molecular activator (activation), whereas the pattern of knots resulted from changes in both activation and biases in tooth bud growth. In simulations, increased activation facilitated accelerated evolutionary increases in knot number, creating a lateral knot arrangement that evolved at least ten times on placental upper molars. Relatively small increases in activation, superimposed on an ancestral tritubercular molar growth pattern, could recreate key changes leading to a rectangular upper molar cusp pattern. Tinkering with tooth bud geometry varied the way cusps initiated along the posterolingual molar margin, suggesting that small spatial variations in ancestral molar growth may have influenced how placental lineages acquired a hypocone cusp. We suggest that development could have enabled relatively fast higher-level divergence of the placental molar dentition.

scholarly journals Dental evolutionary rates and its implications for the Neanderthal–modern human divergence

2019 ◽  
Vol 5 (5) ◽  
pp. eaaw1268 ◽  
Author(s):  
Aida Gómez-Robles
Keyword(s):  
Divergence Time ◽  
Modern Human ◽  
Evolutionary Rates ◽  
Middle Pleistocene ◽  
Last Common Ancestor ◽  
Modern Humans ◽  
Bayesian Analyses ◽  
Sima De Los Huesos ◽  
Dental Evolution ◽  
Quantitative Analyses

The origin of Neanderthal and modern human lineages is a matter of intense debate. DNA analyses have generally indicated that both lineages diverged during the middle period of the Middle Pleistocene, an inferred time that has strongly influenced interpretations of the hominin fossil record. This divergence time, however, is not compatible with the anatomical and genetic Neanderthal affinities observed in Middle Pleistocene hominins from Sima de los Huesos (Spain), which are dated to 430 thousand years (ka) ago. Drawing on quantitative analyses of dental evolutionary rates and Bayesian analyses of hominin phylogenetic relationships, I show that any divergence time between Neanderthals and modern humans younger than 800 ka ago would have entailed unexpectedly rapid dental evolution in early Neanderthals from Sima de los Huesos. These results support a pre–800 ka last common ancestor for Neanderthals and modern humans unless hitherto unexplained mechanisms sped up dental evolution in early Neanderthals.

scholarly journals From mechanisms to function: an integrated framework of animal innovation

2016 ◽  
Vol 371 (1690) ◽  
pp. 20150195 ◽  
Author(s):  
Sabine Tebbich ◽  
Andrea S. Griffin ◽  
Markus F. Peschl ◽  
Kim Sterelny
Keyword(s):  
Adaptive Radiation ◽  
Evolutionary Significance ◽  
Morphological Adaptation ◽  
Novel Food ◽  
Integrated Framework ◽  
Experimental Approaches ◽  
Evolutionary Consequences ◽  
Selection Of ◽  
The Way

Animal innovations range from the discovery of novel food types to the invention of completely novel behaviours. Innovations can give access to new opportunities, and thus enable innovating agents to invade and create novel niches. This in turn can pave the way for morphological adaptation and adaptive radiation. The mechanisms that make innovations possible are probably as diverse as the innovations themselves. So too are their evolutionary consequences. Perhaps because of this diversity, we lack a unifying framework that links mechanism to function. We propose a framework for animal innovation that describes the interactions between mechanism, fitness benefit and evolutionary significance, and which suggests an expanded range of experimental approaches. In doing so, we split innovation into factors (components and phases) that can be manipulated systematically, and which can be investigated both experimentally and with correlational studies. We apply this framework to a selection of cases, showing how it helps us ask more precise questions and design more revealing experiments.

scholarly journals Evolution of the locomotor skeleton in Anolis lizards reflects the interplay between ecological opportunity and phylogenetic inertia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Nathalie Feiner ◽  
Illiam S. C. Jackson ◽  
Edward L. Stanley ◽  
Tobias Uller
Keyword(s):  
Adaptive Radiation ◽  
Morphological Diversity ◽  
Evolutionary Rates ◽  
Greater Antilles ◽  
Ecological Opportunity ◽  
Morphological Diversification ◽  
Phylogenetic Inertia ◽  
Evolutionary Trajectories ◽  
Repeated Evolution ◽  
Variable Evolutionary Rates

AbstractAnolis lizards originated in continental America but have colonized the Greater Antillean islands and recolonized the mainland, resulting in three major groups (Primary and Secondary Mainland and Greater Antillean). The adaptive radiation in the Greater Antilles has famously resulted in the repeated evolution of ecomorphs. Yet, it remains poorly understood to what extent this island radiation differs from diversification on the mainland. Here, we demonstrate that the evolutionary modularity between girdles and limbs is fundamentally different in the Greater Antillean and Primary Mainland Anolis. This is consistent with ecological opportunities on islands driving the adaptive radiation along distinct evolutionary trajectories. However, Greater Antillean Anolis share evolutionary modularity with the group that recolonized the mainland, demonstrating a persistent phylogenetic inertia. A comparison of these two groups support an increased morphological diversity and faster and more variable evolutionary rates on islands. These macroevolutionary trends of the locomotor skeleton in Anolis illustrate that ecological opportunities on islands can have lasting effects on morphological diversification.

Prediction and validation of avascular tumor growth pattern in different metabolic conditions using in silico and in vitro models

2021 ◽  
pp. 2150024
Author(s):  
Mahshid Heidari ◽  
Mahboubeh Kabiri
Keyword(s):  
Tumor Growth ◽  
Computational Model ◽  
Growth Pattern ◽  
In Silico ◽  
Cell Activity ◽  
In Vitro Models ◽  
Growth Behavior ◽  
Cell Counting ◽  
Modeling Framework

Objectives: In recent years, scientists have taken many efforts for in vitro and in silico modeling of cancerous tumors. In fact, three-dimensional (3D) cultures of multicellular tumor spheroids (MCTSs) are good validators for computational results. The goal of this study is to simulate the 3D early growth of avascular tumors using MCTSs and to compare the in vitro models with the results and predictions of a specific computational modeling framework. Using these two types of models, the importance of metabolic condition on tumor growth behavior and necrosis could be predicted. Materials and methods: We took advantage of a previously developed computational model of tumor growth (constructed by integrating a generic metabolic network model of cancer cells with a multiscale agent-based framework). Among the computational predictions is the importance of glucose accessibility on tumor growth behavior. To study the effect of glucose concentration experimentally, MCTSs were grown in high and low glucose culture media. After that, tumor growth pattern was analyzed by MTT assay, cell counting and propidium iodide (PI) staining. Results: We obviously observed that the rate of necrosis increases and the rate of tumor growth and cell activity decreases as the glucose availability reduces, which is in line with the computational model prediction.

scholarly journals EVOLUTIONARY RATES IN THE ADAPTIVE RADIATION OF BEETLES ON PLANTS

Evolution ◽  
2004 ◽  
Vol 58 (9) ◽  
pp. 1984-2001 ◽  
Author(s):  
Brian D. Farrell ◽  
Andrea S. Sequeira
Keyword(s):  
Adaptive Radiation ◽  
Evolutionary Rates

EVOLUTIONARY RATES IN THE ADAPTIVE RADIATION OF BEETLES ON PLANTS*

Evolution ◽  
2004 ◽  
Vol 58 (9) ◽  
pp. 1984 ◽  
Author(s):  
Brian D. Farrell ◽  
Andrea S. Sequeira
Keyword(s):  
Adaptive Radiation ◽  
Evolutionary Rates

scholarly journals Higher evolutionary rates in life-history traits in insular than in mainland palms

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cibele Cássia-Silva ◽  
Cíntia G. Freitas ◽  
Larissa Pereira Lemes ◽  
Gustavo Brant Paterno ◽  
Priscila A. Dias ◽  
...  
Keyword(s):  
Life History ◽  
Adaptive Radiation ◽  
Life History Traits ◽  
Fruit Size ◽  
Habitat Type ◽  
Taxonomic Diversity ◽  
Evolutionary Rates ◽  
Volcanic Island ◽  
Optimal Value ◽  
Volcanic Islands

AbstractIsolated islands, due to the reduced interspecific competition compared to mainland habitats, present ecological opportunities for colonizing lineages. As a consequence, island lineages may be expected to experience higher rates of trait evolution than mainland lineages. However, island effects on key life-history traits of vascular plants remain underexplored at broad spatiotemporal scales, even for emblematic island clades such as palms. Here, we used phylogenetic comparative methods to evaluate potential differences in size and macroevolutionary patterns of height and fruit diameter among mainland, continental, and volcanic island palms. Further, phylogenetic beta-diversity was used to determine if lineage turnover supported an adaptive radiation scenario on volcanic islands. Volcanic island palms were taller than their continental island and mainland counterparts, whereas continental island palms exhibited smaller fruit size. Height and fruit size of palms evolved under evolutionary constraints towards an optimal value. However, scenarios of adaptive radiation and niche conservatism were not supported for the height and fruit size of volcanic and mainland palm clades, respectively, as expected. Instead, continental island palms exhibited higher evolutionary rates for height and fruit size. Insular palm assemblages (continental and volcanic) are composed of unique lineages. Beyond representing evolutionary sources of new palm lineages, our results demonstrate that insular habitats are important in shaping palm trait diversity. Also, the higher phenotypic evolutionary rates of continental island palms suggest disparate selection pressures on this habitat type, which can be an important driver of trait diversification over time. Taken together, these results stress the importance of insular habitats for conservation of functional, phylogenetic, and taxonomic diversity of palms.

scholarly journals Which one is better: Assessment and Locomotion imitation strategies in Changing Environments

2021 ◽  
Vol 2113 (1) ◽  
pp. 012034
Author(s):  
Cunying Chen ◽  
Hua Zhang
Keyword(s):  
Computational Model ◽  
Performance Feedback ◽  
Environmental Changes ◽  
Self Regulation ◽  
Dynamic Environments ◽  
Uncertain Environments ◽  
Mode Theory ◽  
Changing Environments ◽  
Regulatory Mode

Abstract Imitation is ubiquitous, yet what self-regulation orientations’ role played in imitation strategies is poorly understood, which is particularly challenging in dynamic and uncertain environments. According to regulatory mode theory, we model two imitation strategies: assessment and locomotion. Assessment pays more attention on comparation among different alternatives, they repeatedly measure, evaluate, and compare desired means and try to find out the ‘best’ one. Contrariwise locomotion refers to ‘keep moving’, once choosing one alternative, they change some choices and learn from the resulting performance feedback. Using a computational model, we explore the performance implications of dynamic environments for these two imitation strategies. Consequently, when environment is stable, assessment is more effective in maintaining the lead, whereas locomotion prevails as environmental changes become more frequent and substantial. We contribute to the literatures on strategy, imitation, and NK studies.

scholarly journals Continental cichlid radiations: functional diversity reveals the role of changing ecological opportunity in the Neotropics

2016 ◽  
Vol 283 (1836) ◽  
pp. 20160556 ◽  
Author(s):  
Jessica Hilary Arbour ◽  
Hernán López-Fernández
Keyword(s):  
Central America ◽  
Adaptive Radiation ◽  
Morphological Diversity ◽  
Evolutionary Rates ◽  
Ecological Niches ◽  
Ecological Opportunity ◽  
Ecological Release ◽  
Adaptive Radiations ◽  
Lineage Diversification

Adaptive radiations have been hypothesized to contribute broadly to the diversity of organisms. Models of adaptive radiation predict that ecological opportunity and ecological release, the availability of empty ecological niches and the response by adapting lineages to occupy them, respectively, drive patterns of phenotypic and lineage diversification. Adaptive radiations driven by ‘ecological opportunity’ are well established in island systems; it is less clear if ecological opportunity influences continent-wide diversification. We use Neotropical cichlid fishes to test if variation in rates of functional evolution is consistent with changing ecological opportunity. Across a functional morphological axis associated with ram–suction feeding traits, evolutionary rates declined through time as lineages diversified in South America. Evolutionary rates of ram–suction functional morphology also appear to have accelerated as cichlids colonized Central America and encountered renewed opportunity. Our results suggest that ecological opportunity may play an important role in shaping patterns of morphological diversity of even broadly distributed lineages like Neotropical cichlids.

Community evolution in Greater Antillean Anolis lizards: phylogenetic patterns and experimental tests

1995 ◽  
Vol 349 (1327) ◽  
pp. 69-75 ◽  
Keyword(s):  
Puerto Rico ◽  
Habitat Use ◽  
Adaptive Radiation ◽  
Driving Force ◽  
Phylogenetic Analyses ◽  
Experimental Tests ◽  
Small Islands ◽  
Ecological Interactions ◽  
Morphological Adaptation ◽  
Community Evolution

Phytogenies can be useful not only as a means of examining evolutionary hypotheses, but also as a source of hypotheses that can be tested using extant taxa. I illustrate this approach with examples from the study of community evolution in Caribbean Anolis lizards. Phylogenetic analyses indicate that not only are Anolis communities on Jamaica and Puerto Rico convergent in structure, but they have attained their similarity by evolving through a nearly identical sequence of ancestral communities. Examination of the pattern of community evolution suggests that interspecific competition is the driving force behind anole adaptive radiation. This hypothesis can be tested by investigating whether anoles shift their habitat use in the presence of competitors and, if so, whether such shifts lead to morphological adaptation to the new habitat. These hypotheses have been tested experimentally by introducing lizards onto small islands. Preliminary results indicate the existence of ecological interactions among sympatric anoles and that shifts in habitat use are accompanied by microevolutionary changes in morphology.

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