AZSCI Crosscutting: Cause and Effect

Question 1

A scientist observes that in a particular forest, years with higher-than-average spring rainfall are followed by summers with a greater number of wildfires. Which of the following describes a plausible mechanism that would establish this correlation as a cause-and-effect relationship, rather than a simple coincidence?

Accepted Answer

The abundant spring rain leads to rapid growth of underbrush, which then dries out in the summer, providing more fuel for fires.

Answer

This choice provides a testable mechanism linking the cause (heavy rain) to the effect (more wildfires). The rain causes an intermediate effect—the growth of fuel (underbrush)—which then leads to the final effect. This demonstrates that cause-and-effect relationships often have underlying mechanisms that explain how the cause leads to the effect. Answer A suggests correlation, not causation. Answer B is a less likely direct mechanism. Answer D introduces a human factor that isn't directly linked to the natural phenomenon of rainfall.

Question 2

In climate science, a 'positive feedback loop' is a specific type of cause-and-effect relationship. Which of the following scenarios best illustrates a positive feedback loop?

Accepted Answer

Melting of Arctic sea ice exposes darker ocean water, which absorbs more solar radiation, leading to further warming and more ice melt.

Answer

A positive feedback loop is a process where the effect of an action amplifies the original action, creating a reinforcing cycle. In this case, warming causes melting, which causes more warming, which causes more melting. The other options describe negative (balancing) feedback loops, where the effect counteracts the initial cause, leading to stabilization.

Question 3

Some cause-and-effect relationships in complex systems, like quantum mechanics or genetics, can only be described using probability. This is known as probabilistic causation. How does this differ from deterministic causation?

Accepted Answer

In probabilistic causation, a cause is not guaranteed to produce the effect every time, but it increases the likelihood of the effect occurring.

Answer

Probabilistic causation implies that a cause changes the probability of an effect's occurrence, rather than guaranteeing it. For example, exposure to a carcinogen (cause) increases the probability of developing cancer (effect), but doesn't guarantee it for every individual. Deterministic causation, often seen in classical mechanics, implies that if the cause occurs, the effect is inevitable and will follow with 100% certainty.

Question 4

In a non-linear system, the relationship between cause and effect is not proportional. Which of the following is the best example of a non-linear cause-and-effect relationship?

Accepted Answer

Adding a single grain of sand to a stable sandpile has no effect, but adding that same grain later causes a massive avalanche.

Answer

This scenario exemplifies a non-linear relationship, often associated with complex systems and tipping points. A very small cause (one grain of sand) can lead to a disproportionately large effect (an avalanche) because the system's state is near a critical threshold. The other examples all describe linear relationships where the effect is directly proportional to the cause.

Question 5

In a complex ecological system, a sudden increase in the population of a primary predator leads to a decrease in its main prey. This, in turn, causes a decline in a scavenger species that relies on the predator's leftover kills. The decline of the scavenger then allows a specific type of fungus, which the scavenger used to disturb, to flourish. This chain of events is best described as an example of:

Accepted Answer

An indirect cause-and-effect relationship.

Answer

This scenario illustrates an indirect cause-and-effect relationship. The initial cause (increase in predators) does not directly affect the fungus. Instead, it triggers a series of intermediate events (decrease in prey, then decrease in scavengers) that ultimately lead to the effect on the fungus. Simple linear relationships involve a direct link (A causes B), while feedback loops involve a cycle where the output affects the initial input. Correlation without causation would mean the events happened together by chance or due to a third, unmentioned factor.

(AZSCI) Arizona Science Test Practice Test

(AZSCI) Arizona Science Test Practice Test

AZSCI Crosscutting: Cause and Effect