Succession Review Answer Key 1. Draw a picture of primary succession. Tell what types of plants/trees are in each stage. Tell whether each stage has pioneer, intermediate, and/or climax community. 2. You have inherited a fifty-acre abandoned farm field from a tree hugging back-to-nature woman who insists that the property be maintained in such a way that it will revert to the condition it was in prior to human intervention. A. How would the property move through the stages of succession? • • • • • Follow the pattern of secondary or old field succession. Grasses would first overtake the plowed land. Shrubs would start to come in, and eventually take over the grass. Shrubs would then be replaced by softwood trees that favor sunlight, like pines and cedars. Eventually hardwood trees would take over, like maples and oaks, forming a climax community. 2. You have inherited a fifty-acre abandoned farm field from a tree hugging back-to-nature woman who insists that the property be maintained in such a way that it will revert to the condition it was in prior to human intervention. B. How would you protect the area from the modern problems that would affect it? Consider nonnative species and other factors that did not exist prior to human intervention. • • • • Refrain from planting ornamental plants, allowing the native species more space to thrive Clean up trash and food around the area to preserve the natural habitats and eating patterns of the wildlife. Prevent deer from eating the saplings Remove invasive plants 3. What are two ways that you can recognize if a species is a dominant species in a community? • • How much ground it covers (Ex. Trunks of trees) How much light it captures (Ex. Leaves of trees) 4. Explain how the BHT, frequency, and abundance can help you figure out what stage of succession the community is in. • The BHT will tell you which species is dominant, and the frequency and abundance will give you an idea of how many of the different types of trees there are. • For example: • If softwood trees are more abundant and dominant, you can tell that the forest is at an intermediate stage. • The presence of young hardwood trees (low BHT) tells you that the forest is transitioning into a climax community. 5. Which type of succession would occur faster… primary or secondary? Give reasons to support your answer. • • • Secondary succession will occur faster. Soil or bottom sediment is already in place from an earlier existing ecosystem (possibly destroyed by a fire or flood). Seeds of earlier plants might still exist in the soil and can quickly grow into new plants, given enough water and sunlight. 6. A forest fire just wiped out our plot next to the Timberlane tennis courts. What are two positive scenarios that could come out of this? • • Increased levels of biodiversity if the plants are allowed to grow back naturally More stable environment because of the increased biodiversity. 7. Which stage of succession demonstrates the most stability? Explain your reasoning. • • • The climax community demonstrates the most stability. These stage of succession has the greatest variety of living things. If some organisms are affected by disease (or some other condition), it will have less of an impact on the ecosystem as a whole because there are other organisms there to help fulfill the role of the afflicted organisms. 8. Name three abiotic factors that play a role in forest succession, and describe their possible effects. • • • Sunlight: Plants have varying tolerances for shade. As succession progresses, there is more shade from the larger plants, and so the smaller grasses and weeds that need sunlight tend to die off. Space: As larger plants move into an area, there is physically less space for the smaller plants to grow and develop. Nutrients: The amount and type of nutrients available changes with the different types of plants. 9. Describe how wildlife can also change with the stages of succession. • Plants determine the types of wildlife you will see in an area. Certain types of herbivores eat certain types of plants, so they will go where the food is. Certain types of plants provide shelter for different types of animals as well. • • • Ex. Squirrels live in trees and eat nuts. You will only find them in mature forests where they find their preferred shelter and food. 10. Are the Timberlane and Hopewell woods in the same stage of succession? • Timberlane has more softwood trees that are indicative of earlier succession. 11. Why is only 10% of the energy passed on from one trophic level to the next? • Energy is lost to respiration • Energy is lost to build the body • Not all of the prey is consumed 12. Why is an ecosystem more sensitive to disruption from the top than it is from the bottom? • The top has more diversity 13. How do detritivores fit into the ecosystem? • They recycle material- not energy • They are essential in a forest, almost all of the nutrients are in the biomass and need to be processed back into the soil.