LIFE SCIENCE

Detailed explanation-1: -Secondary succession is more common and usually occurs faster than primary succession because the substrate is already present. Secondary succession occurs on a surface where an ecosystem has previously existed.

Detailed explanation-2: -Secondary succession is usually faster than primary succession because soil and nutrients are already present due to ‘normalization’ by previous pioneer species, and because roots, seeds and other biotic organisms may still be present within the substrate.

Detailed explanation-3: -Why does secondary succession typically proceed faster than primary succession? Because it mostly occurs on a surface where an ecosystem has previously existed. Primary succession only occurs on a surface where no ecosystem existed before.

Detailed explanation-4: -Secondary succession occurs when the severity of disturbance is insufficient to remove all the existing vegetation and soil from a site. Many different kinds of disturbances, such as fire, flooding, windstorms, and human activities (e.g., logging of forests) can initiate secondary succession.