Life has existed on Earth for billions of years, shaped by dramatic events — explosions of new life forms and mass extinctions. Explore the geological timescale and its key turning points.
Scientists divide Earth's long history into a geological timescale, split into three broad eras (you don't need to memorise exact dates or every period name):
| Era | Roughly |
|---|---|
| Paleozoic | "Ancient life" — began around 541 million years ago (Mya) |
| Mesozoic | "Middle life" — the age of dinosaurs |
| Cenozoic | "New life" — the current era, since 65 Mya |
South Africa has a rich fossil record documenting key events in this history, including trilobites in the Karoo, and evidence of changing sea levels along the coast.
Around 541 Mya, a relatively short period called the Cambrian Explosion saw the rapid appearance of most major animal groups still around today — giving huge insight into the origins of animal diversity.
Throughout Earth's history, there have been five mass extinctions — events where a large percentage of species died out relatively quickly. Two are especially important to know:
In just the last four million years, significant changes have occurred in species found in Africa — including the evolution of humans (studied further in Grade 11 and 12). Today, scientists warn that the current rate of extinction is higher than at almost any point in the past, largely due to human activity — sometimes called the sixth extinction.
Click an event to see where it falls on Earth's timeline (not drawn to a strict linear scale, so early events are still visible).
| Era | Approx. start (Mya) | Approx. end (Mya) |
|---|---|---|
| Paleozoic | 541 | 250 |
| Mesozoic | 250 | 65 |
| Cenozoic | 65 | 0 (present) |