KEYNOTE SPEAKERS
Species invasions are pervasive in Earth’s history, yet the ecological and evolutionary consequences of species invasions vary greatly. Invasion events can be organized in a hierarchy of increasing invasion intensity from ephemeral invasions to globally pervasive invasive regimes. Each level exhibits emergent properties exceeding the sum of interactions at lower levels. The ecological impacts of lower-level impacts can be negligible or result in temporary community accommodation. Invasion events at moderate to high levels of the hierarchy permanently alter quantitative aspects of ecological communities, regional faunas, and global ecosystems. The prevalence of invasive species results in quantifiable evolutionary changes by fostering niche evolution, differential survival of ecologically generalized taxa, faunal homogenization, and suppressing speciation. These impacts can contribute to mass extinctions and biodiversity crises that alter the trajectory of ecological and evolutionary patterns of life. In this talk, we’ll explore the impacts of invasions at various levels of the hierarchy incorporating examples of ephemeral invasions in local strata, the regional Richmondian Invasion, the Great Ordovician Biodiversification Event, the Great American Biotic Interchange, and the Late Devonian Biodiversity Crisis. The fossil record provides a long-term record of how invasion impacts may scale up through time, which can augment ecological studies of modern species invasions.
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Ediacaran fossils occupy a crucial position in the history of life on Earth, marking the transition between 3 billion years of microbial life and the Cambrian explosion of modern animals. The oldest Ediacaran fossils exhibit unique anatomies, making it difficult to resolve the key processes underlying their evolutionary biology. However, the sessile nature of Ediacaran organisms, coupled with their in-situ preservation, means detailed ecological analyses can be used to “reverse engineer” these evolutionary dynamics. In this talk I will discuss how ecological analyses have enabled us to resolve the life-cycles of key species, determine competition dynamics, and investigate the role that stochastic and deterministic processes played within these communities and on early animal evolution.
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Paleontological record holds the only direct evidence on the long-term evolution and ecological change. Theoretical and experimental studies of modern ecological-evolutionary systems show the prevalence of nonlinear processes in the biotal change. Since paleontological record spans many orders of magnitude on the time scale it reflects convolution of complex internal biotic dynamics with external climate systems, which exhibit range of scale free and scale specific dynamic regimes. This overwhelming complexity of paleoecological and evolutionary dynamics requires application of rigorous techniques which can handle non-linearity, stochasticity and non-stationarity of stratigraphic time series. The recurrence plots and recurrence quantification analysis which are based on the dynamical systems theory represent one such a tool. Recurrence is a return of a system to the similar condition, and it is a fundamental property of any system experiencing change. Therefore it can yield insights on some of the long-standing issues in paleontology, for example stability vs. continuity of change, and contingency vs. determinism in biotal evolution. In this talk we will explore some of the applications and modern developments of recurrence plots in characterizations of paleocommunity dynamics in the context of extinction events, their use as an additional tool for stratigraphic correlation, and the detection of time-specific anomalies in dynamics of marine biota and geochemical records.
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Irresectable of their exact date of origin, birds are well diversified already in the early Cretaceous, i.e. when undoubted avians first occur in the fossil record. As expected, a variety of morphologically primitive taxa (often resembling non-avian dinosaurs in their body-plan and osteology) are known from this epoch, but these ones co-occur with morphologically derived forms, appearing to be very close to the modern radiation of birds. The origin and early evolutionary history of modern-birds (the clade Ornithuromorpha) is not clear, as no clearly transitional forms are known. It is generally believed that the origin of Ornithuromorpha is linked with the basal divergence of the clade Ornithothoraces, which also includes the so-called opposite birds, Enantiornithes. In my presentation I will discuss a possible alternative hypothesis of the origin of morphologically modern birds, which I proposed recently – this links Ornithuromorpha with one particular group of opposite birds. I will further discuss the ecological prerequisites for the evolutionary formation of Ornithuromorpha, and trace their early adaptations.
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