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:
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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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