Search results for "evolution"
showing 10 items of 11096 documents
Language, Childhood, and Fire: How We Learned to Love Sharing Stories.
2022
Stories do not fossilize. Thus, exploring tales shared during prehistory, the longest part of human history inevitably becomes speculative. Nevertheless, various attempts have been made to find a more scientifically valid way into our deep human past of storytelling. Following the social brain hypothesis, we suggest including into the theory of human storytelling more fine-grained and evidence-based findings (from archaeology, the cognitive sciences, and evolutionary psychology) about the manifold exaptation and adaptation, genetic changes, and phenotypic plasticity in the deep human past, which all shaped the emergence of storytelling in hominins. We identify three preconditions for humans…
Increasing temperature and productivity change biomass, trophic pyramids and community‐level omega‐3 fatty acid content in subarctic lake food webs
2021
Climate change in the Arctic is outpacing the global average and land-use is intensifying due to exploitation of previously inaccessible or unprofitable natural resources. A comprehensive understanding of how the joint effects of changing climate and productivity modify lake food web structure, biomass, trophic pyramid shape and abundance of physiologically essential biomolecules (omega-3 fatty acids) in the biotic community is lacking. We conducted a space-for-time study in 20 subarctic lakes spanning a climatic (+3.2 degrees C and precipitation: +30%) and chemical (dissolved organic carbon: +10 mg/L, total phosphorus: +45 mu g/L and total nitrogen: +1,000 mu g/L) gradient to test how temp…
Carbon dynamics in highly heterotrophic subarctic thaw ponds
2015
Abstract. Global warming has accelerated the formation of permafrost thaw ponds in several subarctic and arctic regions. These ponds are net heterotrophic as evidenced by their greenhouse gas (GHG) supersaturation levels (CO2 and CH4), and generally receive large terrestrial carbon inputs from the thawing and eroding permafrost. We measured seasonal and vertical variations in the concentration and type of dissolved organic matter (DOM) in five subarctic thaw (thermokarst) ponds in northern Quebec, and explored how environmental gradients influenced heterotrophic and phototrophic biomass and productivity. Late winter DOM had low aromaticity indicating reduced inputs of terrestrial carbon, wh…
Increasing concentration of polyunsaturated fatty acids in browning boreal lakes is driven by nuisance algaGonyostomum
2020
Elevated concentrations of dissolved organic carbon (DOC) promote browning of lakes, which alters the physicochemical properties of water and ecosystem functioning. However, browning‐induced changes in basal production of polyunsaturated fatty acids from the n‐3 and n‐6 families (n‐3 and n‐6 PUFA) in lakes are not fully understood. The concentrations of PUFA, which are micronutrients required to maintain growth and reproduction of consumers, have been suggested to either rise or decline in seston as a response to lake browning. Elevated DOC concentrations may also promote bacterial biomass and production and thus potentially increase the concentration of bacterial fatty acids (BAFA) in sest…
Coupling of iron and dissolved organic matter in lakes–selective retention of different size fractions
2023
AbstractIncreasing concentration of iron (Fe) is observed in many boreal lakes, such as for the present study in Oslo Østmark, SE-Norway (1983–2018). As Fe-regulating processes are complex and dynamic, the link between mobilizing and retention processes is still not well understood. A seasonal study (2017–2018) from two headwaters, with medium and high dissolved organic matter (DOM) concentrations, showed that the loading of Fe to the lakes was highly dependent on flow conditions. Significantly higher values of Fe were related to autumn and winter periods with high runoff of highly colored and aromatic DOM compared to a severe drought period with minimum Fe values in the lakes. Compared to …
Metabolic plasticity of mixotrophic algae is key for their persistence in browning environments
2022
Light availability is the main regulator of primary production, shaping photosynthetic communities and their production of ecologically important biomolecules. In freshwater ecosystems, increasing dissolved organic carbon concentrations, commonly known as browning, leads to lower light availability and the proliferation of mixotrophic phytoplankton. Here, a mixotrophic algal species (Cryptomonas sp.) was grown under five increasing dissolved organic carbon concentrations to uncover the plastic responses behind the success of mixotrophs in browning environments and their effect in the availability of nutritionally important biomolecules. In addition to the browning treatments, phototrophic, …
Co-evolution between streaming and live music leads a way to the sustainable growth of music industry : Lessons from the US experiences
2017
While digitization of music, particularly streaming services, has gained increasing popularity, it has also led to a steady decline in the revenues of recorded music industry. This is causing strong concern regarding a potential collapse of the music industry comparable to other print media industries such as newspaper and book publishing. However, recent changes in the music industry initiated by a resurgence of the live music industry are giving rise to some expectations for the survival and growth of the music industry. The parallel paths of increasing popularity of streaming services and a resurgence of live music suggest that these two dynamics are working together in a co-evolutionary…
Red-list of Italian bryophytes. 1. Liverworts and hornworts
2023
The objective of this study is to provide an updated conservation status of all liverworts and hornworts in the Italian territory, evaluated according to IUCN's Guidelines for Application of IUCN Red List Criteria at Regional Level. Overall, 27.4% of taxa assessed in this study are assigned to a risk category and, therefore, considered threatened in Italy. Four liverworts are considered as Extinct, two liverworts and one hornwort Possibly Extinct at regional level. Moreover, a further 9.8% are assessed as Near Threatened, 10.8% as Data Deficient and 49.7% as Least Concern. Most threats are co-occurring, indicating that many taxa are subjected to a set of correlated adverse processes. The ma…
Genome-wide mapping of signatures of selection using a high-density array identified candidate genes for growth traits and local adaptation in chicke…
2023
Abstract Background Availability of single nucleotide polymorphism (SNP) genotyping arrays and progress in statistical analyses have allowed the identification of genomic regions and genes under selection in chicken. In this study, SNP data from the 600 K Affymetrix chicken array were used to detect signatures of selection in 23 local Italian chicken populations. The populations were categorized into four groups for comparative analysis based on live weight (heavy vs light) and geographical area (Northern vs Southern Italy). Putative signatures of selection were investigated by combining three extended haplotype homozygosity (EHH) statistical approaches to quantify excess of haplotype homoz…
Biology of the sauropod dinosaurs: the evolution of gigantism
2010
The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to ha…