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  • richardmitnick 9:28 am on January 26, 2022 Permalink | Reply
    Tags: "Unravelling the mysteries of the first land plants", , , , , Cardiff University [Prifysgol Caerdydd](WLS), , , Eophytes, Lacking physical evidence the authors stop short of drawing direct connections between the two types of fossils., Paleobotany, The discovery of eophytes brings us one step closer to confirming the ancestral polysporangiophyte and suggests promising threads to follow but also presents further questions., The discovery of the eophytes raises the question of their position in the evolutionary relationship as well as implications for character evolution deep in the history of land plants., The eophytes could be the ancestral polysporangiophytes., The evidence available is inconclusive as to whether tracheid-based water-conducting tissue and sporophyte branching evolved simultaneously in the common ancestor of vascular plants or in a sequence., The School of Earth and Environmental Sciences documented fossils bearing similarities to plants still in existence.   

    From Cardiff University [Prifysgol Caerdydd](WLS): “Unravelling the mysteries of the first land plants” 

    From Cardiff University [Prifysgol Caerdydd](WLS)

    25 January 2022
    Professor Dianne Edwards
    Research Professor

    1
    Recent palaeobotanical research on early terrestrial ecosystems hints at the existence of a novel and previously unknown major group of early land plants.

    Twin papers from Professor Dianne Edwards and her team, published in the journal New Phytologist, [here and here] have uncovered pieces of a persistent puzzle, which, when solved, will provide the key to a better understanding of the early evolution of land plants.

    Through careful examination of minute fossils preserved in charcoal from the earliest Devonian strata (c. 415 Myr old) and detailed comparative work on existing plants, research led by the School of Earth and Environmental Sciences documented fossils bearing similarities to plants still in existence. Lacking physical evidence the authors stop short of drawing direct connections between the two types of fossils. Nevertheless, the fossils provide evidence for the existence of a major group of early plants called the eophytes.

    The eophytes are best understood in the context of the early history of land plants. All living vascular plants share vascular tissues containing specialised water-conducting cells known as tracheids, for which they are referred to as tracheophytes, and branched sporophytes, which underpin their classification as polysporangiophytes. These two characters separate vascular plants from the nonvascular plant lineages collectively referred to as bryophytes, which are comprised of mosses, liverworts, and hornworts.

    The evidence available is inconclusive as to whether tracheid-based water-conducting tissue and sporophyte branching evolved simultaneously in the common ancestor of vascular plants, or in a sequence. And, if so, in what order the evolution occurred. The discovery of eophytes brings us one step closer to confirming the ancestral polysporangiophyte and suggests promising threads to follow, but also presents further questions.

    The eophytes could be the ancestral polysporangiophytes, if their branched sporophytes and food-conducting cells evolved in concert and not sequentially – a question that can be solved only by new fossil discoveries.

    The discovery of the eophytes raises the question of their position in the evolutionary relationship as well as implications for character evolution deep in the history of land plants. Given their combination of characters, of which different subsets are shared with the bryophytes and with polysporangiophytes, the eophytes could occupy several positions in the evolution of early land plants. To address this, Professor Edwards advocates for further comparative studies of densely sampled extant bryophyte lineages for the anatomy and ultrastructure of the food-conducting cells.

    The incongruence between patterns of relationships implied by the traditional evolutionary sequence and the sequence of appearance of polysporangiophyte characters is deepened by the discovery of eophytes. This further complicates the mystery in two other directions. First, it indicates that a lot was happening in morphological evolution during the Silurian and Early Devonian (c. 445–400 Ma) and much of that is unknown, for now. Second, it shows that some of the evolutionary changes that are vital to untangling patterns of relationships were occurring at very small scales in these organisms.

    The first direction points to the incomplete exploration of the fossil record and suggests another important thread to follow: renewed investigations of the Silurian and Lower Devonian rock records for new plant fossils. The second indicates that integrating the new fossils in evolutionary discussions will necessitate observations of fine anatomical and ultrastructural detail, which will require fossil localities where the quality of preservation allows for levels of observational detail like those reported by the eophyte fossils.

    The work of Professor Edwards and her team, including Jennifer Morris and Lindsey Axe (Cardiff University), Wilson Taylor (The University of Wisconsin-Eau Claire (US)), Jeffrey Duckett, Paul Kenrick, and Silvia Pressel (The Natural History Museum-London (UK)), adds an important chapter demonstrating the irreplaceable role of fossils in probing the deepest recesses of plant evolution.

    See the full article here .


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    The Cardiff Unversity [Prifysgol Caerdydd] (WLS) is a public research university in Cardiff, Wales. Founded in 1883 as the University College of South Wales and Monmouthshire (University College Cardiff from 1972), it became a founding college of the University of Wales in 1893. It merged with the University of Wales Institute of Science and Technology (UWIST) in 1988 to form the University of Wales College, Cardiff (University of Wales, Cardiff from 1996). In 1997 it received its own degree-awarding powers, but held them in abeyance. The college adopted the public name Cardiff University in 1999; in 2005 this became its legal name, when it became an independent university and began awarding its own degrees.

    Cardiff University is the third oldest university in Wales and contains three colleges: Arts, Humanities and Social Sciences; Biomedical and Life Sciences; and Physical Sciences and Engineering. It is the only Welsh member of The Russell Group Association(UK). In 2018–2019, Cardiff had a turnover of £537.1 million, including £116.0 million in research grants and contracts. It has an undergraduate enrolment of 23,960 and a total enrolment of 33,190 (according to HESA data for 2018/19) making it one of the ten largest UK universities. The Cardiff University Students’ Union works to promote student interests in the university and further afield.

    Discussions on the founding of a university college in South Wales began in 1879, when a group of Welsh and English MPs urged the government to consider the poor provision of higher and intermediate education in Wales and “the best means of assisting any local effort which may be made for supplying such deficiency.”

    In October 1881, William Gladstone’s government appointed a departmental committee to conduct “an enquiry into the nature and extent of intermediate and higher education in Wales”, chaired by Lord Aberdare and consisting of Viscount Emlyn, Reverend Prebendary H. G. Robinson, Henry Richard, John Rhys and Lewis Morris. The Aberdare Report, as it came to be known, took evidence from a wide range of sources and over 250 witnesses and recommended a college each for North Wales and South Wales, the latter to be located in Glamorgan and the former to be the established University College of Wales in Aberystwyth (now Aberystwyth University [Prifysgol Aberystwyth](WLS)). The committee cited the unique Welsh national identity and noted that many students in Wales could not afford to travel to universities in England or Scotland. It advocated a national degree-awarding university for Wales, composed of regional colleges, which should be non-sectarian in nature and exclude the teaching of theology.

    After the recommendation was published, Cardiff Corporation sought to secure the location of the college in Cardiff, and on 12 December 1881 formed a University College Committee to aid the matter. There was competition to be the site between Swansea and Cardiff. On 12 March 1883, after arbitration, a decision was made in Cardiff’s favour. This was strengthened by the need to consider the interests of Monmouthshire, at that time not legally incorporated into Wales, and the greater sum received by Cardiff in support of the college, through a public appeal that raised £37,000 and a number of private donations, notably from the Lord Bute and Lord Windsor. In April Lord Aberdare was appointed as the College’s first president. The possible locations considered included Cardiff Arms Park, Cathedral Road, and Moria Terrace, Roath, before the site of the Old Royal Infirmary buildings on Newport Road was chosen.

    The University College of South Wales and Monmouthshire opened on 24 October 1883 with courses in Biology, Chemistry, English, French, German, Greek, History, Latin, Mathematics and Astronomy, Music, Welsh, Logic and Philosophy, and Physics. It was incorporated by Royal Charter the following year, this being the first in Wales to allow the enrollment of women, and specifically forbidding religious tests for entry. John Viriamu Jones was appointed as the University’s first Principal at the age of 27. As Cardiff was not an independent university and could not award its own degrees, it prepared its students for examinations of The University of London (UK) or for further study at The University of Oxford (UK) or The University of Cambridge (UK).

    In 1888 the University College at Cardiff and that of North Wales (now Bangor University [Prifysgol Bangor](WLS)) proposed to the University College Wales at Aberystwyth joint action to gain a university charter for Wales, modelled on that of Victoria University (UK), a confederation of new universities in Northern England. Such a charter was granted to the new University of Wales in 1893, allowing the colleges to award degrees as members. The Chancellor was set ex officio as the Prince of Wales, and the position of operational head would rotate among heads of the colleges.

    In 1885, Aberdare Hall opened as the first hall of residence, allowing women access to the university. This moved to its current site in 1895, but remains a single-sex hall. In 1904 came the appointment of the first female associate professor in the UK, Millicent Mackenzie, who in 1910 became the first female full professor at a fully chartered UK university.

    In 1901 Principal Jones persuaded Cardiff Corporation to give the college a five-acre site in Cathays Park (instead of selling it as they would have done otherwise). Soon after, in 1905, work on a new building commenced under the architect W. D. Caröe. Money ran short for the project, however. Although the side-wings were completed in the 1960s, the planned Great Hall has never been built. Caroe sought to combine the charm and elegance of his former (Trinity College, Cambridge) with the picturesque balance of many Oxford colleges. On 14 October 1909 the “New College” building in Cathays Park (now Main Building) was opened in a ceremony involving a procession from the “Old College” in Newport Road.

    In 1931, the School of Medicine, founded as part of the college in 1893 along with the Departments of Anatomy, Physiology, Pathology, Pharmacology, was split off to form the Welsh National School of Medicine, which was renamed in 1984 the University of Wales College of Medicine.

    In 1972, the institution was renamed University College Cardiff.

     
  • richardmitnick 10:06 am on September 3, 2020 Permalink | Reply
    Tags: "The growth and decline in Rapa Nui's population is a lesson for our future", A detailed study shows that the islanders on Rapa Nui suffered at least three societal crises during the centuries after colonization., , , , Paleobotany, Rapa Nui is also known as Easter Island., Secretive monumental statues called moai were carved between the years 1250CE and 1500CE., The population on Rapa Nui didn't crash because the Europeans came. Nor did they live in idyllic equilibrium with nature for centuries., University of Oslo   

    From University of Oslo [Titan.uio.no.]: “The growth and decline in Rapa Nui’s population is a lesson for our future” 

    1

    From University of Oslo

    1 September, 2020

    Mauricio Lima
    Departamento de Ecología
    Pontificia Universidad Católica de Chile, Santiago, Chile
    mlima@bio.puc.cl

    Nils Chr. Stenseth
    The Faculty of Mathematics and Natural Sciences
    University of Oslo
    n.c.stenseth@mn.uio.no

    1
    Secretive monumental statues, called moai, carved between the years 1250CE and 1500CE.
    The researchers studied the history of Rapa Nui because they were trying to understand what is happening with the planet today. Credit: Bjørn Christian Tørrissen/Wikimedia Commons CC BY-SA 3.0.

    The population on Rapa Nui didn’t crash because the Europeans came. Nor did they live in idyllic equilibrium with nature for centuries.

    Rapa Nui—also known as Easter Island—is one of the most remote inhabited islands in the world. The island is also surrounded by several myths, legends and narratives, not least because of the secretive monumental statues, called moai, carved between the years 1250 and 1500. Norwegian explorer Thor Heyerdahl’s Kon-Tiki expedition in 1947 also draw a lot of attention towards Rapa Nui.

    An interdisciplinary group with 11 scientists from Chile, Spain and Norway has now delivered a strong rebuttal of some of the narratives concerning Rapa Nui and the island’s population.

    Nobody knows exactly when the first humans settled on Rapa Nui, but some historians believe that a small group of Polynesian settlers arrived already around 800 to 900 A.D. On the other end of the scale, everybody agrees that Rapa Nui was populated around 1200 A.D.

    From then on, the settlers on Rapa Nui went through a succession of crises. The new study shows that the crises were linked to the long-term effects of climate change on the capacity for food production on the island.

    A controversial history

    Paleobotanical studies indicate that the island was forested when the first settlers arrived, with a range of trees, shrubs, ferns, and grasses. However, land clearing for cultivation and the introduction of the Polynesian rat led to gradual deforestation, so that Rapa Nui today is mostly covered in grassland.

    2
    This digital reconstruction shows what the interior of Rapa Nui may have looked like, with tropical forest and palm trees, before the first settlers arrived. Today, Rapa Nui is a more barren island covered in grassland. Illustration: Rod 6807/Wikimedia Commons.

    “The history of the population of Rapa Nui history has been quite controversial, and there have been two big hypotheses about its development. One of them is the ecocide hypothesis, stating that the population once suffered a big collapse because they overexploited the natural resources on the island. The other hypothesis is that a collapse occurred after the Europeans came to the island. Our research show that neither of these hypotheses are correct,” says Professor Mauricio Lima from University Católica de Chile in Santiago.

    3
    A typical landscape on Easter Island today; rounded extinct volcanoes covered in low vegetation. Photo: Bjørn Christian Tørrissen/Wikimedia Commons.

    “There is also a myth about the population on Rapa Nui living in an idyllic equilibrium with nature for centuries. That is not true either,” says Professor Nils Chr. Stenseth from the University of Oslo, Norway. The scientific report presenting their new findings was published in the journal Proceedings of the Royal Society Bin June and has drawn a lot of attention.

    Three societal crises

    A more detailed study shows that the islanders on Rapa Nui suffered at least three societal crises during the centuries after colonization. The first crisis is dated to 1450-1550, during the Little Ice Age. A less apparent decline occurred between the arrival of the first Europeans in 1772 and 1774, for reasons still unknown. There was also a crisis during the nineteenth century, due to the introduction of epidemic diseases and the slave trade. Therefore: No idyllic equilibrium, and no single big crash in the population.

    Mauricio Lima and Nils Chr. Stenseth wanted to take a closer look at the rise and fall of the population on Rapa Nui, because they suspected that there was a lesson to be learnt. And they were right. First, they gathered a lot of available data from earlier studies of archeological sites, variations in the Pacific climate, changes in the population size through the centuries, changes in forestation and agricultural practices on the island, and so on.

    Then, they integrated all the data into a scientific model based on classical population ecology theory.

    “We have used this model several times before, when we wanted to identify the reasons behind the changes in populations of other animal species like small rodents or fish species. This was a small human population on a small island with limited resources, and it seemed obvious that the model could produce interesting results,” professor Stenseth says to Titan.uio.no.

    “In order to understand what is going to happen with a population at a future point in time, you have to know what happened before”, he adds.

    When Stenseth and Lima used their model and theories to analyse the data from Rapa Nui, the conclusion soon became quite clear.

    “The demographic declines of the Rapa Nui are linked to the long-term effects of climate change on the island’s capacity for the production of food”, explains Mauricio Lima.

    They were struggling to survive

    The researchers and their scientific report describe how a small and fluctuating population struggled for survival on a small and remote island in the Pacific Ocean, in an environment that was – and is – constantly changing. This area is strongly affected by the El Niño–Southern Oscillation (ENSO), which is an irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean.

    The warming phase of the sea temperature is known as El Niño and the cooling phase as La Niña. The new report shows that Rapa Nui is most sensitive to cold ENSO phases – La Niña – which leads to decreased rainfall over the island. This in turn reduces the overall capacity for food production on the island.

    “We did not find traces of an idyllic equilibrium with nature, and we did not find traces of a huge collapse. Instead, we found traces of interactions between three factors: Climate change, human population size, and changes in the ecosystem. The climate change manifests itself as a long-term pattern of changes in rainfall over some 400 years. The population grew during this same period, and the islanders also increased and changed their use of natural resources and agricultural methods”, Lima explains.

    This explains why there were no “idyllic equilibrium” on Rapa Nui: It is difficult to achieve an equilibrium when the natural surroundings are constantly changing.

    Nils Chr. Stenseth and Mauricio Lima agree that the people on Rapa Nui were well aware of the ongoing changes in climate and ecology and the need to adapt.

    “My view is that the islanders were not only aware of the changes, but they were also able to change the way the lived on the island. They gradually changed from the quite complex society that raised the marvellous moai statues, to a later and simpler agrarian society with reduced family sizes and a new way of producing food in stone gardens”, says Lima.

    Rapa Nui yesterday is like the world today.

    Both Mauricio Lima and Nils Chr. Stenseth emphasize that their new results are not relevant only for Rapa Nui. Similar things happened on a lot of other islands in Polynesia. But the importance does not stop there:

    “The population on Rapa Nui lived – and live – on a small and remote island with limited resources, and we ourselves are living on a small and remote planet with limited resources. One of the lessons from this study is the importance of interactions between climate change, human population size and changes in the ecosystem”, says Professor Lima.

    “These three factors affected the population on Rapa Nui, and they are also important on a global scale. We studied Rapa Nui and its history because we are trying to understand what is happening with the planet. Everybody talks about climate change and the resulting problems, but very few people are talking about the rising global population and the problems it causes”, Lima adds.

    “I completely agree with Mauricio. The human population on Planet Earth is under the influence of ecological processes, just like any other animal species in a limited environment”, adds Nils Chr. Stenseth.

    A scientific controversy

    Professor Stenseth admits that the researchers behind this new report are stepping into the middle of a scientific controversy.

    “In the past, many scientists working on this subject from an archaeological or sociological point of view have had a tendency to ignore nature, to ignore ecological processes. We have in fact witnessed a fragmentation inside science, because ecologists and historians/archaeologists have been living in different worlds. What we did in this paper was to bring together different competences, both archaeologists and ecologists, in order to develop a deeper understanding. That is a main message from this work”, Stenseth insists.

    “This is very true. The interdisciplinary approach is necessary for understanding Rapa Nui – and the world we live in,”, Lima adds.

    Thor Heyerdahl as an inspiration

    The first recorded European contact with Rapa Nui happened in 1722, when Dutch navigator Jacob Roggeveen arrived with three ships on April 5 – Easter Sunday. The Dutch sailors immediately started to use Easter Island as a name, and this stuck until long after Thor Heyerdahl arrived in 1948. In recent years, the island is usually called by the name used by the indigenous population.

    Today, Rapa Nui is famous at least partly because of Heyerdahl – even if he is no longer considered as the best of scientists. But he was a great storyteller and thus served as an inspiration to both Mauricio Lima and Nils Chr. Stenseth.

    “Thor Heyerdahl is almost a household name also in my home country, and I remember reading some of his books when I was a teenager and finding them very exciting. Later on, I more or less forgot about Heyerdahl when I started to study biology and ecology. I did not think much about him until Nils asked me about gathering data from archaeological sites at Rapa Nui a few years ago. Then, it all came back to me”, recounts Professor Lima.

    See the full article here.

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