According to a study published by researchers at the University of Cambridge in the open access journal Public Library of Science Biology on the 17th, early animals formed complex ecological communities more than 550 million years ago, laying the foundation for the Cambrian outbreak. The first animals evolved at the end of the Ediacaran period about 580 million years ago.
However, the fossil record shows that after the initial prosperity, the diversity decreased in the preparatory stage of the rapid germination of biodiversity in the "Cambrian explosion" nearly 40 million years later. Scientists believe that this decline in diversity is evidence of mass extinction about 550 million years ago and may be caused by environmental disasters, but previous studies have not investigated the structure of these ancient ecological communities.
To assess evidence of the Ediacaran mass extinction, the researchers analyzed the meta community structure of three fossil assemblages that spanned the last 32 million years of the geological period (575 million to 543 million years ago). They used published paleoenvironmental data, such as ocean depth and rock characteristics, to find meta community structures that indicate environmental specificity and species interactions. This analysis reveals the increasingly complex community structure in the late fossil assemblage, which indicates that species become more specific and participate in more inter species interactions at the end of the Ediacaran, which is a common trend in the process of ecological succession.
The results show that competitive exclusion rather than mass extinction led to the decline of diversity in the late Ediacaran. The analysis shows that the ecological and evolutionary dynamic characteristics usually associated with the Cambrian outbreak, such as community complexity and niche adaptation, were established by the first animal communities in the late Ediacaran. Ediacaran was the fuse that ignited the Cambrian explosion.
