Primary Succession
• Defined: Establishment and development of an
ecosystem in an uninhabited environment
• Starts with bare rock
•Volcanic activity
– Lava cools and hardens into rock, forming new
land.
•Glaciers retreat
– New land is exposed and ready to be
inhabited.
Pioneer Species
• Defined: First organisms to inhabit new land
– Moss and lichen grow on bare rock
– Dead matter and crumbling rock  first layer of soil.
The Process Continues
• Seeds grow in the new soil.
• Small flowers & shrubs build up more
organic matter
• Small animals and insects.
The Process Continues
• Enough soil to support small trees
• Animals use the trees as a habitat
Climax Community
• Large trees take root
– Crowd in and compete with smaller trees
• Large animals inhabit new forests
Secondary Succession
• Defined: Rebuilding an ecosystem after a
disaster
– Forest fires, floods, tree falls…
Occurs at a faster rate
- Soil already exists
- Dead matter returns nutrients to
soil
Review
1) What are the first organisms to live within a newly created
patch of land called?
2) Give examples of the answer to question #1.
3) What are the final organisms to live within a newly created
patch of land called?
4) How are new areas of land created?
5) Give a few examples how the process of secondary
succession can start.
6) How does primary and secondary succession differ?