Eukaryotes begin to diversify
Ornamented microfossils multiply in form, the first sign of an evolutionary radiation.
- When
- Known to
- ± 100 million years
- Era
- Mesoproterozoic, Proterozoic
From around 1.4 billion years ago the variety of acritarchs — resistant organic-walled microfossils, most likely algal cysts — increases markedly, with spines, plates and complex wall structures appearing. Distinct species become useful for dating rocks for the first time. It is modest compared with later radiations, but it contradicts the idea that nothing evolved during this interval.