Primary successions begin at a place previously deprived of life. For example, on frozen lava after volcanic eruptions, on sea islands after earthquakes, on sand dunes, on bare rocks, river deposits. Secondary successions begin at the site of the destroyed ecosystem. An example is the overgrowing of abandoned fields, deforestation, polluted water bodies, restoration of meadows and forests after a fire, drought, flood, erosion.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.