• Social networking for fossils shows comm

    From ScienceDaily@1:317/3 to All on Mon Feb 28 21:30:40 2022
    Social networking for fossils shows community impacts of mass
    extinctions

    Date:
    February 28, 2022
    Source:
    University of Texas at Austin
    Summary:
    By applying an algorithm akin to what social media sites use to
    make friend suggestions, researchers have identified communities
    of ancient life in the fossil record and tracked how their numbers
    changed through each of the planet's mass extinctions.



    FULL STORY ==========================================================================
    By applying an algorithm akin to what Facebook uses to make friend
    suggestions, researchers have identified communities of ancient life in
    the fossil record and tracked how their numbers changed through each of
    the planet's mass extinctions.


    ==========================================================================
    As expected, the number of communities -- a group of different species
    living in the same general area -- dropped during mass extinction
    events. But the rate at which communities disappeared did not always
    track with the overall loss of life and biodiversity during an extinction,
    a result that suggests that the ecological impacts of an extinction are
    not always linked with the number of species that perish.

    "There have been times in our history where there have been major
    events that saw tremendous changes in communities, but very few species disappeared," said lead author Drew Muscente, who conducted the study
    when he was a postdoctoral researcher at The University of Texas at
    Austin's Jackson School of Geosciences. "And there have been events where
    many species had disappeared and communities and ecosystems were barely affected at all." Muscente is now an assistant professor at Cornell
    College. The study was recently published in the journal Geology.

    The results underscore the importance of studying communities to get a
    broader perspective on environmental change -- both in the past and in
    the present.

    "We try to understand how changes in these communities lead to fundamental transformation of entire ecosystems," said coauthor Rowan Martindale,
    an associate professor at the Jackson School.



    ========================================================================== Identifying communities in the fossil record is notoriously
    difficult. Most research on paleocommunities focuses on comparing samples
    and collections of fossils that have been taken from rocks of various ages
    and locations. And although conventional computational methods can be used
    to group samples into paleocommunities, they work best with relatively
    small datasets of only a few hundred or thousand fossil collections. Due
    to this limitation, the conventional methods can only be applied to data
    from specific regions and time periods, as opposed to the entire record.

    The researchers were able to overcome these challenges and examine
    the entire fossil record by applying a community detection algorithm
    based on network analysis methods. Social media companies are known for
    using these sorts of methods to connect users, but they are becoming increasingly applied across a range of scientific disciplines.

    According to Muscente, this study is the first time that network analysis
    has been applied to detect paleocommunities throughout the entire fossil
    record of marine animal life -- from when animal life first appeared to
    the current geologic era.

    Matthew Clapham, a paleobiology professor at the University of
    California Santa Cruz who was not involved with the study, said that
    another advantage of the network analysis method is the emphasis on
    visualizing connections, rather than just the types of animals present
    in an ecosystem.

    "It brings the analysis closer to the way that the communities actually
    worked because communities and interactions between species are networks,"
    he said.



    ========================================================================== Drawing on a database of 124,605 collections of marine animal fossils
    from around the world, and representing 25,749 living and extinct
    animal groups, or genera, the algorithm identified more than 47 million
    links between these samples and organized them into 3,937 distinct paleocommunities.

    The study tracked the communities and biodiversity over the past 541
    million years. The research showed that while mass extinction events
    took a toll on both, the degree of decline sometimes differed.

    Some extinctions affected communities more than biodiversity. Some
    affected biodiversity more than communities. And some affected both
    about the same.

    Furthermore, the researchers did not find a link between the cause
    of an extinction and whether it took a great toll on communities or biodiversity.

    The results indicate that the larger ecological impacts of extinction
    are more about which species are lost rather than the number of species
    lost. If an environment's key players are preserved, communities can
    remain intact. But if too many of these players are removed, the community crumbles with it.

    Muscente said he hopes that the network analysis methods first applied
    in this study can be improved and used to study modern ecosystems.

    "I'd like to try and bridge the gap from the rock record to the present,"
    he said.

    The study's other coauthors include scientists at the Rensselaer
    Polytechnic Institute, the University of Idaho, the Carnegie Institution
    for Science and Harvard University.

    The research was funded by the Keck Foundation, the Deep Carbon
    Observatory, the Alfred P. Sloan Foundation, the Carnegie Institution
    for Science and the National Science Foundation.

    ========================================================================== Story Source: Materials provided by University_of_Texas_at_Austin. Note: Content may be edited for style and length.


    ========================================================================== Related Multimedia:
    *
    An_example_of_network_with_connections_between_various_forms_of_ancient
    sea_life ========================================================================== Journal Reference:
    1. A.D. Muscente, Rowan C. Martindale, Anirudh Prabhu, Xiaogang
    Ma, Peter
    Fox, Robert M. Hazen, Andrew H. Knoll. Appearance and disappearance
    rates of Phanerozoic marine animal paleocommunities. Geology,
    2021; 50 (3): 341 DOI: 10.1130/G49371.1 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/02/220228103821.htm

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