Succession - the process by which organisms occupy an uninhabited space
Primary Succession: has no soil. When there is rock, sand, volcanic ash or any other place with no nutrients, then organisms will occupy the space in a predictable way:
Steps
1. rock, sand, volcanic ash
2. pioneer species arrive: moss, lichen. These die and become humus, which becomes soil.
3. more nutrients allow the seeds of grasses, weeds, and flowers to become established. Now earthworms, beetles, microbes work on the soil
4. more nutrients allow the seeds of bushes to come and grow
5. Next fast growing trees like deciduous trees
6. a mature community of shade tolerant deciduous and coniferous (evergreen trees) come.
Secondary succession
Steps
1. soil already exists, such as after a major disaster like fire, flooding, clear cutting
2. grasses, weeds, flowers, beetles, earthworms, microbes
3. bushes
4. fast growing trees , deciduous.
5. mature community of large trees, deciduous and conifers (evergreens)
