Which of the following is the best definition of primary succession?

Question

1. Primary succession is the introduction of plant life on newly formed soils or soils that were previously uninhabited.

2. Primary succession is the reintroduction of plant life in areas that were previously occupied but have undergone a disturbance.

3.Primary succession is the destruction of plant life due to human pressures.

4. Primary succession is the destruction of plant life due to natural pressure such as fire.

5. None of the above

Answer 1

Primary succession is the gradual growth of organisms in an area that was previously bare, such as rock. (For example lichens, mosses, and ferns will first appear on bare rock.)

Answer 2

Choice #5 would probably be the best of the options available.

#1 is close, but primary succession involves the formation of soil from a pristine substrate (i.e. a recently cooled lava flow, rock exposed from glacial retreat, or an abandoned strip mine) by colonizing organic lifeforms, so technically the plants introduced to newly formed soil would most likely be early secondary succession (since they would be replacing lichens etc. that were present originally to facilitate soil formation).

#2, 3, and 4 all describe secondary succession (disturbances of the existing order).