Question

Imagine you are an explorer who has just discovered two previously unknown large islands. Each island has a population of a species of shrub unknown elsewhere. On Island A, the shrubs have high concentrations of certain poisonous chemicals in their leaves. On Island B, the shrubs have nonpoisonous, edible leaves. The islands differ in many ways—for instance, Island A has less rainfall and a colder winter than Island B, and it has some plant-eating insects that are not found on Island B. Island A also has a large population of muntjacs, a small tropical deer that loves to eat shrubs. You suspect the muntjacs have been the selective force that has caused evolution of leaf toxins. How could you test this hypothesis? What alternative hypotheses can you think of? What data would disprove your hypothesis, and what data would disprove the other hypotheses?

a. How could you test the hypothesis of muntjacs causing evolution of leaf toxins?
b. What are the alternative hypotheses for the evolution of leaf toxins?
c. What data would support the muntjacs hypothesis?
d. What data would disprove the alternative hypotheses?

Answer 1

To test the hypothesis of muntjacs causing evolution of leaf toxins, manipulations of the presence or absence of muntjacs on the islands can be conducted, while alternative hypotheses for the evolution of leaf toxins could include abiotic stressors or the presence of other herbivores or insect pests.

Step-by-step explanation:

To test the hypothesis of muntjacs causing evolution of leaf toxins, you could conduct an experiment where you manipulate the presence or absence of muntjacs on the islands. On Island A, you could remove all muntjacs and observe if the shrubs still produce high concentrations of poisonous chemicals. On Island B, you could introduce muntjacs and see if the shrubs start evolving toxins. If the presence or absence of muntjacs directly affects the evolution of leaf toxins, then the data would support the muntjacs hypothesis.

The alternative hypotheses for the evolution of leaf toxins could include natural factors such as abiotic stressors like temperature or rainfall, or the presence of other herbivores or insect pests. To disprove these alternative hypotheses, you could conduct experiments where you manipulate the abiotic factors or the presence of other herbivores or insect pests and observe if the shrubs still evolve leaf toxins. If the shrubs continue to evolve toxins regardless of these factors, then the alternative hypotheses would be disproven.