Andrej Spiridonov
@andrejpaleo
Professor of paleontology and Earth systems at Vilnius University. My interests are: theoretical paleontology, evolution, geology, stratigraphy, philosophy of biology and geology, climate at scales great and small.
Special, and dearest to my heart, kind of paleontology which is known by very few
Different languages have different granularities for taxonomies of things. Depends on what is important. In Lithuanian, where horses are culturally important (as with Arabs and Mongolians), for example, there are 8 words to call "horse" and with color and physical kind variations--tens of them.
Really interesting work, which explores the biotic and abiotic #Bretskyan_hierarchy determinants of intraspecific population variability - the fuel of evolution. onlinelibrary.wiley.com/doi/epdf/10.... 🧪 #Geology #EvoBio #Macroecology
Many interesting talks at the EAVP23 at Vilnius. Dirley Cortes presents new data on the origins of extremely long-necked elasmosaurs. She also gave very interesting background of predator rich Early Cretaceous ecosystems of marine Colombia, with longest trophic chains. 🧪 ⚒️ #Paleobio
Interesting paper on Abelisaurid ornamentation: "...ordered evolutionary patterns in cranial ornamentation that are more consistent with expectations of sexual selection than with the stochastic patterns predicted under the species recognition hypothesis." doi.org/10.1017/pab.... 🧪 #EvoBio #Paleobio
Does the exception proves the rule? Or exception is just an exception? Maybe larger sizes of fruiting bodies had a spatial structure and "were waiting" for the right conditions in the future? The Cenozoic still shows permanent shift to larger fruit sizes. www.science.org/doi/epdf/10.... 🧪 #Geology
Such a process produces great "lacunas of inaction" and periods of "high concentration of events". And this happens hierarchically. So, you should expect to have 'events inside events inside events' effect. The graptolite time scales, also, curiously enough, follow the same scaling laws.
They found qualitatively the same pattern (just at shorter scales) as implied by 'compound multifractal - Poisson process' of stratigraphical boundaries www.sciencedirect.com/science/arti... . The probability of significant event is modulated hierarchically and concentrated to smallest scales.
Big conclusion—extinctions are impulsive at all scales: "...extinction in the graptoloids is not stochastically uniform but includes many more high-rate pulses than expected under a null model of uniform, memoryless extinction" doi.org/10.1017/pab.... 🧪 #EvoBio #Paleobio #Geology #Macroecology
Amazing diamond patters of the silver poplar (Populus alba) bark
#Bretskyan_hierarchy "the increase of genus age is associated with a decline in origination proportions and with increasing β-diversities. This contradicts the hypothesis of a simple Phanerozoic sorting toward extinction resistance and generalization." doi.org/10.1017/pab.... 🧪 ⚒️ #Paleobio #EvoBio
This is what I've found by flushing out the air conditioner's water from a tank — the reddish 'Sahara dust' transported here into Lithuania 3000 km from the south, from places like Atlas Mountains, Mali or Chad. 🧪 ⚒️ #Geology
"We study when model selection is unnecessary or can even be harmful for predictive performance in finite data regimes and.. need for selecting simpler models can depend on prior choice..predictively consistent priors, which keep prior predictive implications stable as model complexity increases." 🧪
Plants are exciting evolved multilevel hydraulic-mechanical structures, and allometric scaling laws help us understand how their architecture really works. "Light intensity significantly regulates size-dependent variation in allometric scaling exponents" 🧪 #EvoBio