Primary Succession: When no soil is present and the ground is new. Pioneer species will colonise to form new land.
Secondary Succession: When the soil is already present as is the nutrients. eg deforestation occurred.
Explanation of Primary Succession (and slight secondary)
Primary Succesion occurs from bare land. A pioneer species, that has speciallaiy adapted mechanisms may have been blown in. Due to the limitation of water (abiotic), it needs to have special adapatations. The Pioneer species changes the abiotic conditions, by dying and being decomposed by microorganisms, which helps to form soil and nutrients. This makes the conditions less hostile, so other larger species can grow. As they die, the soil gets richer in nutrients and minerals.
Secondary happens in exactly the same way, except at a later stage due to their already being a layer of soil present. At different stages, other larger plant will…