scholarly journals Ancient origin of high taxonomic richness among insects

2016 ◽  
Vol 283 (1824) ◽  
pp. 20152476 ◽  
Author(s):  
Matthew E. Clapham ◽  
Jered A. Karr ◽  
David B. Nicholson ◽  
Andrew J. Ross ◽  
Peter J. Mayhew
Keyword(s):  
Evolutionary History ◽  
Animal Species ◽  
Environmental Drivers ◽  
Ecological Interactions ◽  
Time Intervals ◽  
The Past ◽  
Fossil Insect ◽  
The Earth ◽  
Family Level ◽  
History Of

Insects are a hyper-diverse group, comprising nearly three-quarters of all named animal species on the Earth, but the environmental drivers of their richness and the roles of ecological interactions and evolutionary innovations remain unclear. Previous studies have argued that family-level insect richness increased continuously over the evolutionary history of the group, but inclusion of extant family records artificially inflated the relative richness of younger time intervals. Here we apply sampling-standardization methods to a species-level database of fossil insect occurrences, removing biases present in previous richness curves. We show that insect family-richness peaked 125 Ma and that Recent values are only 1.5–3 times as high as the Late Palaeozoic. Rarefied species-richness data also tentatively suggest little or no net increase in richness over the past 125 Myr. The Cretaceous peak in family richness was coincident with major radiations within extant groups but occurred prior to extinctions within more basal groups. Those extinctions may in part be linked to mid-Cretaceous floral turnover following the evolution of flowering plants. Negligible net richness change over the past 125 Myr implies that major radiations within extant groups were offset by reduced richness within groups that are now relict or extinct.

scholarly journals Extensive introgression and mosaic genomes of Mediterranean endemic lizards

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Weizhao Yang ◽  
Nathalie Feiner ◽  
Catarina Pinho ◽  
Geoffrey M. While ◽  
Antigoni Kaliontzopoulou ◽  
...  
Keyword(s):  
Evolutionary History ◽  
Mediterranean Islands ◽  
The Past ◽  
Island Endemics ◽  
Extant Species ◽  
Mediterranean Island ◽  
History Of ◽  
Entire History ◽  
The Mediterranean ◽  
The Mediterranean Basin

AbstractThe Mediterranean basin is a hotspot of biodiversity, fuelled by climatic oscillation and geological change over the past 20 million years. Wall lizards of the genus Podarcis are among the most abundant, diverse, and conspicuous Mediterranean fauna. Here, we unravel the remarkably entangled evolutionary history of wall lizards by sequencing genomes of 34 major lineages covering 26 species. We demonstrate an early (>11 MYA) separation into two clades centred on the Iberian and Balkan Peninsulas, and two clades of Mediterranean island endemics. Diversification within these clades was pronounced between 6.5–4.0 MYA, a period spanning the Messinian Salinity Crisis, during which the Mediterranean Sea nearly dried up before rapidly refilling. However, genetic exchange between lineages has been a pervasive feature throughout the entire history of wall lizards. This has resulted in a highly reticulated pattern of evolution across the group, characterised by mosaic genomes with major contributions from two or more parental taxa. These hybrid lineages gave rise to several of the extant species that are endemic to Mediterranean islands. The mosaic genomes of island endemics may have promoted their extraordinary adaptability and striking diversity in body size, shape and colouration, which have puzzled biologists for centuries.

Obituary notices of fellows deceased

1877 ◽  
Vol 25 (171-178) ◽  
Keyword(s):  
Past History ◽  
The Past ◽  
The Earth ◽  
History Of ◽  
Reign Of Terror ◽  
Accurate Observation

George Poulett Scrope. It is scarcely possible at the present day to realize the conditions of that intellectual “reign of terror” which prevailed at the commencement of the present century, as the consequence of the unreasoning prejudice and wild alarm excited by the early progress of geological inquiry. At that period, every attempt to explain the past history of the earth by a reference to the causes still in operation upon it was met, not by argument, but by charges of atheism against its propounder; and thus Hutton’s masterly fragment of a ‘Theory of the Earth,’ Playfair’s persuasive‘ Illustrations,’ and Hall’s records of accurate observation and ingenious experiment had come to be inscribed m a social Index Expurgatorius ,and for a while, indeed, might have seemed to be consigned to total oblivion. Equally injurious suspicions were aroused against the geologist who dared to make allusion to the important part which igneous forces have undoubtedly played in the formation of certain rocks; for the authority of Werner had acquired an almost sacred cha­racter; and “ Vulcanists ” and “ Huttonians ” were equally objects of aversion and contempt. To two men who have very recently—and within a few months of one another—passed away from our midst, science is indebted for boldly en­countering and successfully overcoming this storm of prejudice. Hutton and his friends lived a generation too soon ; and thus it was reserved tor Lyell and Scrope to carry out the task which the great Scotch philosopher had failed to accomplish, namely, the removal of geology from the domain of speculation to that of inductive science.

scholarly journals Defaunation precipitates the extinction of evolutionarily distinct interactions in the Anthropocene

2019 ◽  
Vol 5 (6) ◽  
pp. eaav6699 ◽  
Author(s):  
Carine Emer ◽  
Mauro Galetti ◽  
Marco A. Pizo ◽  
Pedro Jordano ◽  
Miguel Verdú
Keyword(s):  
Seed Dispersal ◽  
Evolutionary History ◽  
Bird Species ◽  
Forest Fragments ◽  
Ecological Interactions ◽  
Rescue Effect ◽  
History Of ◽  
Local Extinctions ◽  
Functional Features ◽  
Avian Seed Dispersal

Species on Earth are interconnected with each other through ecological interactions. Defaunation can erode those connections, yet we lack evolutionary predictions about the consequences of losing interactions in human-modified ecosystems. We quantified the fate of the evolutionary history of avian–seed dispersal interactions across tropical forest fragments by combining the evolutionary distinctness of the pairwise-partner species, a proxy to their unique functional features. Both large-seeded plant and large-bodied bird species showed the highest evolutionary distinctness. We estimate a loss of 3.5 to 4.7 × 104 million years of cumulative evolutionary history of interactions due to defaunation. Bird-driven local extinctions mainly erode the most evolutionarily distinct interactions. However, the persistence of less evolutionarily distinct bird species in defaunated areas exerts a phylogenetic rescue effect through seed dispersal of evolutionarily distinct plant species.

HYSTERESIS EFFECTS IN SOIL MOISTURE MOVEMENT

1962 ◽  
Vol 42 (2) ◽  
pp. 247-253 ◽  
Author(s):  
W. J. Staple
Keyword(s):  
Moisture Content ◽  
Past History ◽  
Rate Of Change ◽  
Moisture Loss ◽  
Time Intervals ◽  
Moisture Movement ◽  
Wetting And Drying ◽  
The Past ◽  
History Of ◽  
Different Depths

Hysteresis was assessed by measuring the tension and moisture content of sections of soil at different time intervals during the redistribution of moisture in uniformly packed columns of Grenville silt loam. Moisture tension was measured by a null method and moisture content was measured gravimetrically.The rate of change of tension with moisture content dψ/dθ and hence the diffusivity, in the tension range 25 to 400 centimeters of water was more than twice as great for drying as for wetting. During redistribution of moisture, when both drying and wetting were involved, different ψ, vs. θ relationships existed at different depths, and the slopes dψ/dθ and diffusivities in the profile were often lower than those for either drying or wetting alone.Further work is needed to assess the importance of hysteresis on moisture movement in practical problems. It seems possible that data on hysteresis, and a knowledge of the past history of wetting and drying, may provide estimates of moisture loss and conservation in fallowed fields.

scholarly journals Ancient origins and multiple appearances of carotenoid-pigmented feathers in birds

2014 ◽  
Vol 281 (1788) ◽  
pp. 20140806 ◽  
Author(s):  
Daniel B. Thomas ◽  
Kevin J. McGraw ◽  
Michael W. Butler ◽  
Matthew T. Carrano ◽  
Odile Madden ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Performance ◽  
Evolutionary History ◽  
Carotenoid Pigments ◽  
Biological Functions ◽  
The Family ◽  
Family Level ◽  
History Of ◽  
Living Species ◽  
Insight Into

The broad palette of feather colours displayed by birds serves diverse biological functions, including communication and camouflage. Fossil feathers provide evidence that some avian colours, like black and brown melanins, have existed for at least 160 million years (Myr), but no traces of bright carotenoid pigments in ancient feathers have been reported. Insight into the evolutionary history of plumage carotenoids may instead be gained from living species. We visually surveyed modern birds for carotenoid-consistent plumage colours (present in 2956 of 9993 species). We then used high-performance liquid chromatography and Raman spectroscopy to chemically assess the family-level distribution of plumage carotenoids, confirming their presence in 95 of 236 extant bird families (only 36 family-level occurrences had been confirmed previously). Using our data for all modern birds, we modelled the evolutionary history of carotenoid-consistent plumage colours on recent supertrees. Results support multiple independent origins of carotenoid plumage pigmentation in 13 orders, including six orders without previous reports of plumage carotenoids. Based on time calibrations from the supertree, the number of avian families displaying plumage carotenoids increased throughout the Cenozoic, and most plumage carotenoid originations occurred after the Miocene Epoch (23 Myr). The earliest origination of plumage carotenoids was reconstructed within Passeriformes, during the Palaeocene Epoch (66–56 Myr), and not at the base of crown-lineage birds.

The Common Fossils of The British Rocks

The Geologist ◽  
1858 ◽  
Vol 1 (1) ◽  
pp. 18-29
Author(s):  
S. J. Mackie
Keyword(s):  
Past History ◽  
Time And Space ◽  
The Road ◽  
The Past ◽  
The Earth ◽  
The World ◽  
History Of ◽  
The Common

In a magazine devoted especially to the propagation of Geological knowledge, it seems no infringement of its space, no deterioration of its value, tha t some pains should be taken to aid the student in his early efforts, and to disperse broadcast some useful elementary information, which may prove to the mass at once a source of instruction and of enjoyment, and so, by clearing the road to future and higher studies, may foster a dawning taste, and ultimately prove the means of adding many volunteers, and not unlikely even some brilliant master-minds to the ranks of Geologists, that otherwise, deterred at the outset, might perhaps have turned their attention and talents to some more accessible, if not more congenial study.Who does not feel some interest in the past history of this beautiful world—the scene of our labours and of our loves—of our successes and of our failures—the stage of our existence and the tomb of our dust ? If the animated creations of the past were dumb brute animals, still the earth was green and gay with trees, and plants and flowers—the hu m of insects vibrated on the summer's air, and the snows of winter covered the ancient lands with their hyemal mantle—the tides of ocean rose and fell, and the world went rolling on through time and space, through years and seasons. There were earthquakes the n and blazing volcanos—and winds and storms—great waves and merry dancing ripples on the sea.

A Discussion on the evolution of the Precambrian crust - Introductory remarks

1973 ◽  
Vol 273 (1235) ◽  
pp. 316-316 ◽  
Keyword(s):  
Early History ◽  
Geological Time ◽  
Precambrian Rocks ◽  
The Past ◽  
Geological Processes ◽  
The Earth ◽  
Large Numbers ◽  
The World ◽  
History Of

The realization that the behaviour of the Earth has changed radically during geological time has come about largely in the last decade. This development, which constitutes one of the major advances in geological thinking, results from the study of Precambrian phenomena in many parts of the world and in particular from the work of a small number of geochronologists. In the last ten years as large numbers of unfossiliferous Precambrian rocks have been dated, it has become clear that the nature of geological processes has varied throughout geological time and that one of the cardinal doctrines of geology - the concept that the present is the key to the past — could not be applied to the study of the early history of the Earth.

scholarly journals The past, present and future of ancient bacterial DNA

2020 ◽  
Vol 6 (7) ◽  
Author(s):  
Nicolas Arning ◽  
Daniel J. Wilson
Keyword(s):  
Demographic Transition ◽  
Dental Plaque ◽  
Evolutionary History ◽  
High Throughput Sequencing ◽  
Industrial Revolution ◽  
Environmental Isolates ◽  
Bacterial Dna ◽  
Content Type ◽  
The Past ◽  
History Of

Groundbreaking studies conducted in the mid-1980s demonstrated the possibility of sequencing ancient DNA (aDNA), which has allowed us to answer fundamental questions about the human past. Microbiologists were thus given a powerful tool to glimpse directly into inscrutable bacterial history, hitherto inaccessible due to a poor fossil record. Initially plagued by concerns regarding contamination, the field has grown alongside technical progress, with the advent of high-throughput sequencing being a breakthrough in sequence output and authentication. Albeit burdened with challenges unique to the analysis of bacteria, a growing number of viable sources for aDNA has opened multiple avenues of microbial research. Ancient pathogens have been extracted from bones, dental pulp, mummies and historical medical specimens and have answered focal historical questions such as identifying the aetiological agent of the black death as Yersinia pestis . Furthermore, ancient human microbiomes from fossilized faeces, mummies and dental plaque have shown shifts in human commensals through the Neolithic demographic transition and industrial revolution, whereas environmental isolates stemming from permafrost samples have revealed signs of ancient antimicrobial resistance. Culminating in an ever-growing repertoire of ancient genomes, the quickly expanding body of bacterial aDNA studies has also enabled comparisons of ancient genomes to their extant counterparts, illuminating the evolutionary history of bacteria. In this review we summarize the present avenues of research and contextualize them in the past of the field whilst also pointing towards questions still to be answered.

scholarly journals Insensitivity of alkenone carbon isotopes to atmospheric CO<sub>2</sub> at low to moderate CO<sub>2</sub> levels

2018 ◽  
Author(s):  
Marcus P. S. Badger ◽  
Thomas B. Chalk ◽  
Gavin L. Foster ◽  
Paul R. Bown ◽  
Samantha J. Gibbs ◽  
...  
Keyword(s):  
Isotope Fractionation ◽  
Isotope Composition ◽  
Ice Core ◽  
Co2 Uptake ◽  
Geological Time ◽  
Time Intervals ◽  
The Past ◽  
The Earth ◽  
Global Carbon ◽  
Carbon System

Abstract. Atmospheric pCO2 is a critical component of the global carbon system and is considered to be the major control of Earth's past, present and future climate. Accurate and precise reconstructions of its concentration through geological time are, therefore, crucial to our understanding of the Earth system. Ice core records document pCO2 for the past 800 kyrs, but at no point during this interval were CO2 levels higher than today. Interpretation of older pCO2 has been hampered by discrepancies during some time intervals between two of the main ocean-based proxy methods used to reconstruct pCO2: the carbon isotope fractionation that occurs during photosynthesis as recorded by haptophyte biomarkers (alkenones) and the boron isotope composition (δ11B) of foraminifer shells. Here we present alkenone and δ11B-based pCO2 reconstructions generated from the same samples from the Plio-Pleistocene at ODP Site 999 across a glacial-interglacial cycle. We find a muted response to pCO2 in the alkenone record compared to contemporaneous ice core and δ11B records, suggesting caution in the interpretation of alkenone-based records at low pCO2 levels. This is possibly caused by the physiology of CO2 uptake in the haptophytes. Our new understanding resolves some of the inconsistencies between the proxies and highlights that caution may be required when interpreting alkenone-based reconstructions of pCO2.

The Measure of the Machine: How Exposure to Current Technology Can Upgrade a Student’s Education

2004 ◽  
Author(s):  
Robert Conger ◽  
Amanda Blum ◽  
Paul A. Erickson
Keyword(s):  
Computer Technology ◽  
Evolutionary History ◽  
The Internet ◽  
Technology In Education ◽  
Computing Power ◽  
Educational Benefits ◽  
The Past ◽  
History Of ◽  
Design Projects ◽  
Remarkable Progress

Over the past decade there has been a distinct trend toward implementing computer technology in education. The advent of affordable, student accessible computing power has allowed engineering curricula to follow the trends of computer technology in the engineering workplace. The developments in hardware and software, combined with the explosive entrance of the Internet, have allowed design projects to evolve into elaborate and imaginative endeavors. The enhanced speed at which projects can now be completed allows students the opportunity to undertake tasks of greater magnitude, while the advanced tools now available permit students to solve more sophisticated and lifelike problems. The examination of a senior-level design course, in which students must design and build a maze-solving robot, serves to highlight the educational benefits that stand to be gained through the judicious application of technology. The evolutionary history of this design course demonstrates the remarkable progress that computer technology has allowed in educational settings.

Sign in / Sign up

Export Citation Format

Share Document