How does the potato crop failure in ireland demonstrate the relationship between humans and the environment? a) because potatoes grew naturally in ireland, people came to rely on them as a main source of food. when the potato crop failed in the 1800s, the irish were able to switch to other agricultural products. b) in the mid—1800s, the potato crops failed in ireland. the loss of this primary food source, combined with harsh british policies, caused about one million people to starve to death. therefore, people relied on the environment for their livelihood. c) the spanish never assisted the irish in methods of growing potatoes effectively. as a result, the irish were not prepared for the airborne virus which killed the potatoes. d) the potato was the main source of food for people in ireland in the mid—1800s. the potato famine shows that the irish should have had a more diverse diet.