1. Ecological Succession…

2. What is Ecological Succession?  The observed process of change in the species structure of an ecological community over time.  A community begins with few pioneering plants and animals and develops through increasing complexity until it becomes stable.  Succession occurs in all natural environments.

3. 1st year Horseweed dominant; crabgrass, pigweed 2nd year Asters dominant; crabgrass 3rd to 18th year Grass scrub community; broomsedge grass, pines coming in during this stage 19th to 30th year Young pine forest 30th to 70th year Mature pine forest; Understory of young hardwoods 70th to 100th year Pine to hardwood transition 100th year plus Climax oak- hickory forest Ecological Succession

4. What are the two main types of succession?  Primary Succession  Secondary Succession

5. Examples of Succession Primary Secondary

6. Primary Succession  The process of creating life in an area where no life previously existed occurs by a process called PRIMARY SUCCESSION.  An example of an area in which a community has never lived before, would be a new lava or rock from a volcano that makes a new island.

7. Primary Succession

8. Secondary Succession  SECONDARY SUCCESSION begins in habitats where communities were entirely or partially destroyed by some kind of damaging event.  When an existing community has been cleared by a disturbance such as a fire, tornado, etc...and the soil remains intact, the area begins to return to its natural community.  Since the soil is already in place, secondary succession can take place five to ten times faster than primary succession.

9. The Circle of Life in Secondary Succession

10. Why Does Ecological Succession Occur?  Because organisms alter soil structure, chemistry, and microclimates, the species composition of ecological communities constantly changes over time.  Succession will continue until the environment reaches it’s final stage…the Climax Community.

11. These are Climax Communities

12. Threats to Succession  The grasses that move in as pioneer species are often thought of as weeds.  The subsequent growth of shrubs are considered undesirable "brush".

13. How Do Humans Affect Ecological Succession?  Clearing the land for the garden and preparing the soil for planting represents a major external event that radically re-structures and disrupts a previously stabilized ecosystem. The disturbed ecosystem will immediately begin a process of ecological succession.  Plant species that adapt to the sunny conditions and the broken soil will rapidly invade the site and will become quickly and densely established. These invading plants are what we call "weeds“ in which we consider a nuisance or invaders.

14. Primary Succession Starts off as rock and slowly over time works its way to full grown forestation.

15. Secondary Succession The process is started by a forest fire and it revives the forest back to full health.

17. Primary Succession

18. Secondary Succession

19. Biogeochemical Cycles

20. Carbon Cycle

21.  Carbon is found in the atmosphere and ocean as carbon dioxide.  Carbon is found on land in organisms, rocks, and soil.  It is found underground as coal and petroleum (fossil fuels).  Plants take in CO2 and use the carbon to build carbohydrates during photosynthesis.  Respiration and Photosynthesis are the two main processes involved in the Carbon Cycle.

22. Nitrogen Cycle

23. Step 1- Nitrogen Fixation- Special bacteria convert the nitrogen gas (N2 ) to ammonia (NH3) which the plants can use. Step 2- Nitrification- Nitrification is the process which converts the ammonia into nitrite ions which the plants can take in as nutrients. Step 3- Ammonification- After all of the living organisms have used the nitrogen, decomposer bacteria convert the nitrogen-rich waste compounds into simpler ones. Step 4- Denitrification- Denitrification is the final step in which other bacteria convert the simple nitrogen compounds back into nitrogen gas (N2 ), which is then released back into the atmosphere to begin the cycle again.

24. Phosphorous Cycle 1. Phosphate is released by the erosion of rocks. 2. Plants and fungi take up the phosphate with their roots. 3. Phosphorus moves from producers to consumers via food chain. 4. Phosphorus may seep into groundwater from soil, over time forming into rock. 5. When these rocks erode, the cycle begins again

26. Water Cycle  Evaporation. The sun heats water in rivers, lakes, and the ocean and turns it into vapor or steam, which then rises into the air.  Transpiration. The evaporation of water from the leaves of plants and trees. Water is added to the atmosphere.  Condensation. The vapor cools and turns into tiny water droplets that attach to each other and form clouds.  Precipitation. Water falls from the clouds as rain, snow, sleet, or hail.  Runoff. Some water stays on the earth’s surface and flows into rivers, lakes, reservoirs, etc.  Percolation. Other water seeps down into the earth’s natural underground reservoirs called aquifers.