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Extinctions

Biology: AQA GCSE Higher, topic 6.3.11

Extinctions

Extinction happens when there are no individuals of a species left in the world. A change in abiotic (physical) or biotic (relating to organisms) factors can cause an extinction if a species cannot adapt or move to another environment.

Rapid extinctions

Rapid extinctions

  • Sometimes abiotic (physical) factors can change rapidly to cause extinctions.
  • Large volcanic eruptions can change the carbon dioxide levels in the atmosphere, block light and cause pH changes in soils.
  • A meteorite or asteroid impact (like the one around the time of the dinosaurs) would have a similar (but larger) effect to a large volcanic eruption.
Slow extinctions

Slow extinctions

  • Geological and atmospheric changes happening over a longer period of time can also cause slower extinctions.

Test yourself on Extinctions

  • What do scientists think caused the extinction of the dinosaurs?

  • What is the main difference between how a volcanic eruption and a slow geological change can cause extinction?

  • What is likely to happen to a species that cannot adapt to the rapid changes in carbon dioxide, light and soil pH caused by a large volcanic eruption?

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