Cambrian (Paleozoic 1)

Paleozoic Era – Time for Ancient Life

The Paleozoic Era, named after the Greek for ‘Ancient Life’  is split into six geological periods.

Paleozoic Era 1: The Cambrian Period – An Explosion in Life

Key Events

  • There is an explosion in the diversity of life on Earth, although there are also ‘extinction events’ where populations are wiped out.
  • Marine life flourishes, but the land remains comparatively barren.
  • The first representatives appear of most of the large groups (‘phyla’) living today.
Illustration of life during the Cambrian Period. Copyright: Vix Southgate

Facts, Debates & Trivia

  • The name comes from ‘Cymru’ (Wales), where Britain’s Cambrian rocks are best exposed.
  • Arthropods (creatures with exoskeletons), like trilobites or shrimps, are very common during this period.
  • The oldest rocks in Cornwall, at Old Lizard Head, form during the Cambrian Period around 500 million years ago.
The Earth Story Trail signs for the Paleozoic Era, which has six geological periods, the Cambrian, the Ordovician, the Silurian , the Devonian, the Carboniferous and the Permian.


  • Seas are relatively warm.
  • Continents are probably dry and rocky.
  • Polar ice is absent for most of the period.
The Earth 540 million years ago. The red dot marks the location of what will eventually become Cornwall. Credit: C.R. Scotese/I. Webster.


541-485.4 million years ago

(53.4 million years)

1 metre = 10 million years

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