The way that Earth’s first animals reproduced held back life’s diversity for millions of years, until stress and competition led to the development of sexual reproduction, which in turn accelerated the pace of evolution.
Co-authors of a new paper, Dr Emily Mitchell and Professor Andrea Manica, who lead our Deep-time Ecology Group and Evolutionary Ecology Group respectively, studied fossils from the oldest-known animals on Earth, dating from 574 million years ago, and found that asexual reproduction slowed the pace of evolution to a crawl, since it limited competition between different groups.
Their results, reported in the journal Nature Ecology and Evolution, could help explain a longstanding puzzle in palaeontology: why animal life appeared on Earth but then barely changed for millions of years, before a second wave of diversification gave evolutionary progress a major boost.
Read more: A lack of sex held back life’s diversity for millions of years
Emily G Mitchell and Andrea Manica. ‘The influence of reproductive mode on resource competition and diversity patterns in Ediacaran early animal communities.’ Nature Ecology and Evolution (2026). DOI: 10.1038/s41559-026-03094-2
Image: Artist's impression of an Ediacaran community Credit: Hugo Salais