Succession

• Primary succession
• Begins in a place without soil
• sand dunes
• sides of volcanoes
• landslides
• flooding/land left after glaciation
• Starts with the arrival of living things such as LICHENS that do  not need soil to survive (called PIONEER SPECIES)
• Lichens - mutualistic relationship between algae and fungus
• algae photosynthesis - fungus absorbs water and minerals and cling onto rocks
• Soil starts to form as lichens and the forces of weather and erosion help break rocks into smaller pieces
• when lichens die, they decompose, adding small amounts of organic matter to the rock to make soil
• simple plants like mosses and ferns can grow in the new soil
• the simple plants die adding ore organic material
• the soil layer thickens and grasses and windflowers and other plants begin to take over
• these plants die thus more nutrients added to the soil
• shrubs and trees can survive
• insects smalls birds and mammals have begun to move in
• what was once a bare rock now supports a variety of life
• Secondary succession
• begins ina place that already has soil and was once a home of living organisms
• occurs faster and has different pioneers species than primary successin
• eg. after forest fires
• Climax community
• a stable group of plants and animals that is the end result of succession pricess
• does not always mean big trees
• grasses in prairies
• cacti in deserts