# Did a lack of sex hold back the evolution of the first animals?

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Podcast: [The Fossil Files](https://stenobird.com/podcast/the-fossil-files-7375611)
Published: 2026-07-14T03:13:00+00:00
Episode link: https://a94020de-22e2-432b-af22-019fdb3026ee.libsyn.com/did-a-lack-of-sex-hold-back-the-evolution-of-the-first-animals
Audio file: https://traffic.libsyn.com/secure/a94020de-22e2-432b-af22-019fdb3026ee/episode_37_ediacaran_balanced.mp3?dest-id=5062010
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Duration seconds: 2955

## Resource

The first animals turned up in the Ediacaran as simple frond-like organisms that didn't do much of anything. Why was this Pre-Cambrian 'Avalonian biota' so static and boring for 12-20 million years before animals started diversifying, moving and becoming more complex? This week we look at a new paper that reconstructs the ecology of the early Avalonian biota, in particular their sexual and and asexual reproductions strategies. To try and figure out what kind of sex these organisms were (or weren't) having, we need to do turn to some interesting maths based on their locations of the fossil surface. This unlocks all sorts of interesting evolutionary dynamics, potentially explaining how animals started to diversify after increasing sexual reproduction and competition in an increasingly dynamic and changeable environment. Life needed chaos! (and sex). This week's paper is "The influence of reproductive mode on resource competition and diversity patterns in Ediacaran early animal communities" by Emily Mitchell and Andrea Manica published in Nature Ecology and Evolution , published June 2026 https://doi.org/10.1038/s41559-026-03094-2 We also mention another paper by Scott Evans ( https://www.science.org/doi/10.1126/sciadv.aed9916) and the story of the discovery of the Ediacaran fossils in Charnwood fossil https://en.wikipedia.org/wiki/Tina_Negus Wide screen art by Hugo Salais.

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