According to a new study led by researchers at the University of Birmingham and involving an international team of collaborators, the number of species within ecological communities on land has increased only sporadically through geological time, with rapid increases in diversity being followed by plateaus lasting tens of millions of years.
Previously, many scientists have argued that diversity increased steadily through geological time, which would mean that biodiversity today is much greater than it was tens of millions of years ago. But building an accurate picture of how land diversity was assembled is challenging because the fossil record generally becomes less complete further back in time. By using modern computing techniques, capable of analysing hundreds of thousands of fossils, patterns are starting to emerge that challenge this view.
Researchers - University - Birmingham - School - Geography
The researchers, from the University of Birmingham's School of Geography, Earth and Environmental Sciences and other institutions in the UK, USA and Australia, were able to study fossil data collected by palaeontologists over the past 200 years at around 30,000 different fossil sites around the globe. The team focused on data from land vertebrates dating back to the very earliest appearance of this group nearly 400 million years ago.
They found that the average number of species within ecological communities of land vertebrates have not increased for tens of millions of years. Their results, published in Nature Ecology & Evolution, suggest that interactions between species, including competition for food and space, will limit the overall number of species that can co-exist.
Lead - Researcher - Dr - Roger - Close
Lead researcher, Dr Roger Close, says: "Scientists often think that species diversity has been increasing unchecked over millions of years, and that diversity is much greater today than it was in the distant past. Our research shows that numbers of species within terrestrial communities are limited over...
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