Suggest two reasons why the tarplant has become endangered.
State three reasons why conserving species is important.
Explain how gibberellin causes germination in seeds.
If tarplant seeds survive for a long time in the soil, the soil acts as a seed store that can help secure the species’ future survival. Very little is known about how long tarplant seeds survive in the soil, or about the proportion of those seeds that can germinate. As a result, researchers used computer models to predict how these factors could influence the chance that the tarplant becomes extinct. The models included: • high or low survival values of tarplant seeds in the soil • different germination percentages of tarplant seeds. The model predictions are shown in Fig. 4.1.
Using Fig. 4.1, describe how each of the following affects the tarplant’s risk of extinction: high seed survival compared with low seed survival of the tarplant seeds different germination percentages of the tarplant seeds.
Using Fig. 4.1, discuss whether soil scraping ought to be recommended as part of the management plan to try to conserve the tarplant.