Self-study
Support The caterpillar of the monarch butterfly feeds on milkweed plants, whose toxins make the adult monarch poisonous to many predators. ███ ███████ ██████████ █████ ████████████ ██ ███ ████ ██ ████████ ███████ ██ ████ ███████ ██ ██████████ ██ ███ ████████ ██████████ ██ ███ ██ █████████ ████ ███ ███████ ██ ██ ██████ ██████ ██ ███████ ██ ███ ██████ ███████████ ██ ███ ████████
Phenomenon-Hypothesis
This stimulus exhibits textbook phenomenon-hypothesis reasoning:
Fact: Monarchs eat milkweed, making them poisonous to predators.
Fact: Viceroys don’t eat milkweed, but they look a lot like monarchs.
Fact: Vireroys are seldom preyed upon.
________
Explanation: They’re seldom preyed upon because they look like the monarch.
We weaken this kind of reasoning by brainstorming alternate explanations for the phenomenon and/or poking holes in the explanation presented to us. It’s worth noodling a bit on these themes in advance. Maybe viceroys also emit a terrible odor (alternate cause). Maybe viceroys and monarchs live in completely different places (poking a hole).
8.
Which one of the following, ██ ██ ████ ██████████ ██ ██ █████ █████ ████ █████████ █████████ ███ █████████
a
Some predators do ███ ████ █ █████ ████████ ██ ███████ ████ ████ ██ ████████ ███████
“Some” is the real killer here. The stimulus accepts
b
Being toxic to █████████ ████ ███ ███████ ██████████ ███████████ ██████ ████ ███████ ██ ███ ███████ ██ █████ ████ ███████████ ██████ ███ █████████ ██████
The causal mechanism at play in the stimulus involves viceroys being protected because of their resemblance to monarchs, not because they themselves are toxic. On the stimulus’ proposed explanation, individual monarchs are protected by their toxicity because most monarchs are toxic, and individual viceroys are protected because they look like monarchs.
c
Some of the █████████ ██ ███ ███████ █████████ ████ ████ ██ █████████
This strengthens the stimulus’ proposed causal mechanism by establishing a connection between the two species – they don’t, for example, live on different continents.
d
The viceroy butterfly ██ █████ ██ ████ ██████████
This provides an alternate explanation for why the viceroys are seldom preyed upon. It’s not because they look like monarchs, it’s because they themselves are poisonous!
(D) is perhaps tricky because the idea that viceroys don’t eat milkweed might suggest they aren’t poisonous. But all it really means is they aren’t milkweed poisonous. They could still be poisonous in other ways.
e
Toxicity to predators ██ ███ █████████ █████ ██ ██████████ ███ ████ █ ███ █████████ ████████
Even if no other species does so, monarch butterflies do use their toxicity to avoid predators. That’s enough to support the stimulus’ proposed explanation that looking like monarchs helps viceroys avoid predators.