Natural Disruptions to Ecosystems
Introduced| English |
|---|
| disruption/dɪsˈrʌpʃn/ |
| periodic/ˌpɪərɪˈɒdɪk/ |
| episodic/ˌepɪˈsɒdɪk/ |
| random/ˈrændəm/ |
Nature shakes things up
- Ecosystems are not always calm and steady.
- Fires burn, storms rage, and floods sweep through.
- These natural events disturb the community and its environment.
- How often they happen shapes how the ecosystem responds.
What a disruption is
- A natural disruption 干扰 is an event that disturbs an ecosystem.
- Fires, storms, floods, droughts, and disease outbreaks are all disruptions.
- They can kill organisms and change the physical environment.
- But they are a normal part of how ecosystems work.
A natural disruption is…
A natural disruption — fire, storm, flood, disease — disturbs an ecosystem's balance.
Sorting by how often
- A periodic 周期性 disruption happens on a regular cycle, like spring floods.
- An episodic 偶发性 disruption is occasional and irregular, like a wildfire every few decades.
- A random 随机 disruption is rare and unpredictable, like a meteor strike.
- The frequency decides how well a community is prepared.
A periodic disruption is one that…
A periodic disruption recurs regularly — like seasonal flooding every spring.
A rare, unpredictable event like a meteor strike is a ____ disruption.
A random disruption strikes rarely and without warning.
Adapted to disturbance
- Ecosystems that face regular disruptions often adapt to them.
- Some pine forests actually need periodic fire to release their seeds.
- After a disturbance, the community usually recovers over time.
- So a natural disruption is not the end — often it renews the ecosystem.
How often does it happen?
Sort each natural disruption by how regularly it occurs - periodic, episodic, or random.
Many ecosystems are adapted to periodic disruptions and recover from them.
Ecosystems evolved with regular disruptions like fire, and often depend on them to stay healthy.
Select all true statements about natural disruptions.
Many ecosystems recover from natural disruptions. The other three are correct.
Natural disruptions are normal, and many ecosystems depend on them. Suppressing all wildfires, for example, lets dead wood build up until one huge, destructive fire results. A regular natural disruption can keep an ecosystem healthier than never disturbing it at all.
Fire and the pine forest:
- Some pines have cones that only open in the heat of a fire.
- Periodic fires clear the undergrowth and release the seeds to sprout.
- Stop all fires, and the forest becomes overgrown and vulnerable — the disruption was part of a healthy cycle.
A natural disruption — fire, storm, flood, disease — disturbs an ecosystem. They vary in frequency: periodic (regular), episodic (occasional), and random (rare, unpredictable). Ecosystems often adapt to and even depend on regular disruptions, and usually recover from them over time.