Seed plants can't take hold on bare rock until soil forms
- The idea
- Predict
- See it
- Why
- Check
The idea
“Plants could grow on bare rock right away if enough seeds landed.”
A sunny, empty patch with seeds blowing in sounds easy to grow on. Roots need soil, and bare rock has none.
The short version
The mistake: Plants could grow on bare rock right away if enough seeds landed.
What's actually true: Bare rock has no soil, so pioneer species like lichens must build it before rooted plants can grow.
- Succession on bare rock, with no soil, is primary succession. Its first species, like lichens, are pioneer species.
- Pioneers help weather the rock and add organic matter when they die. Over many years, that builds soil.
- After a fire or on an abandoned field, the soil is still there. That's secondary succession, and plants return much faster.
On the exam: On bare rock, ask if soil has formed yet. Without soil, more seeds won't help.