The early evolution of animals
The early evolution of animals
The early evolution of animals
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Metazoan evidence 4: Molecular<br />
• Molecular clock<br />
Data<br />
– Genes accumulate changes with time<br />
– Can extrapolate back to see when lineages<br />
diverged<br />
– BUT the rates is not constant!<br />
– Bilaterians calculated to diverge anywhere<br />
between 900 and 570 Ma!<br />
– More recent values tend to value a bilaterian<br />
divergence <strong>of</strong> 570 Ma, closely matching the<br />
fossil record (sponges recently argued to be<br />
earlier - raises taphonomic “issues”)
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