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Study Guide Succession and Catastrophic Events Test Test is May 6, 2011 Succession: A gradual process of predictable changes, that occurs in a community over time. (takes many years) . This change helps an ecosystem achieve balance (stability) Pioneer species: the first species to populate a new area Climax Community: A stable (balanced) end stage of succession where plants and animals use resources efficiently and balance is maintained. This is what completes succession “Nothing succeeds like succession” Primary Succession o Occurs in an area where no previous ecosystem existed. o Begins with bare rock, not soil o Pioneer species are Mosses and Lichens that grow in little to no soil o After soil is formed, grasses, then shrubs and then trees take over the landscape o Takes longer than secondary succession Example: Starts with a volcanic eruption where lava cools into igneous rock. Wind and water bring in moss or lichens and they grow on the rock surface. Wind and water also break down the rock, overtime forming soil Secondary Succession Occurs after a disturbance like a wildfire or hurricane After an ecosystem has been developed Pioneer species are flowers, grasses and weeds Example: A tornado uproots trees and shrubs and destroys grass root systems. The tornado drops debris allover the land. A few months after the tornado, residents notice green grass starting to grow back. Two years later hikers enjoy identifying the small shrubs that have moved in and 10 years later the area is covered with beautiful oak trees Primary Succession (It starts with exposed rock) Increase in time Balanced now Secondary Succession (It starts with a disturbance and soil) In the picture above notice that: 1. After the fire is put out, secondary succession starts 2. The first plants to move in after the fire are small grasses and shrubs 3. As you go through secondary succession you get more types of plant species in your community which increases biodiversity 4. More biodiversity equals more stability. (biodiversity: many different types of plants and animals in a specific area) Catastrophic Events: Flood Rise in water level due to a lot of rain Occurs in low lying areas Can cause animals to move or drown Causes water pollution due to debris and mixing with sewage Tornados o o o o o Mainly found in central US (grasslands) but can be found all over the world, Occurs without much notice Does not last very long but can destroy entire towns Violent whirling winds Can causes secondary succession Hurricanes Starts as a tropical storm over warm ocean waters Can be a few miles wide Last for several days Occurs along coastal areas Strong winds can cause big waves Causes massive erosion and deposition at beaches Can causes secondary succession The center is calm and known as the “eye” Earthquakes o o o o Rocks shift at a plate boundary and faults releasing tension Knocks down buildings If it happens on the ocean floor it can cause a tsunami Can cause secondary succession Volcanoes Can cause primary succession to start if eruption included lava Lava burns plants and animals in it’s path Ash can suffocate animals and block out the sun for several days Wildfires o Puts nutrients back into the soil o Destroys populations of plants and animals that can not move out of the way o Causes secondary succession Droughts Little to no precipitation in a given area over a long period of time Ponds, lakes and aquifers lose water Animals and plants (crops) die Can cause wildfires with heat of sun Can cause secondary succession