Final answer:
A disease affecting oak trees would lead to a decline in primary consumers relying on acorns, subsequently impacting secondary consumers due to reduced prey availability and potentially leading to a collapse of the food web.
Step-by-step explanation:
If a disease affects oak trees, which are primary producers in many ecosystems, this would have significant consequences for various trophic levels in the food web. Since oak trees produce acorns, which serve as a crucial food source for primary consumers such as squirrels and deer, these primary consumers would likely experience a decline in population due to the scarcity of their food source. This decline would ripple through the ecosystem, impacting secondary consumers (e.g., predators like foxes and hawks that eat the primary consumers) as they would face a reduced availability of their prey.
Eventually, this could lead to a potential collapse of the food web, affecting even tertiary consumers. Creatures at the top of the food chain, such as apex predators, might suffer from lack of food, illustrating the interconnected nature of ecosystem components. Therefore, the integrity of the entire ecosystem can be threatened by disturbances at the base, highlighting the importance of producers like oak trees.