Self-study
Support If newly hatched tobacco hornworms in nature first feed on plants from the nightshade family, they will not eat leaves from any other plants thereafter. ████████ ███████ █████████ ████ ████ ██ █████ █████ ██ ██████ ██ ████ ████ ██ ██████ █████ ████ ███████████ ████ █████ █████████ ██ ███████ ████ █████████ ██████████ ███████████ ████ ████ █ ██████████ █████ ████ ██ ████ █ ███████████ ███ █████ █████████ ██████ ██████████ ██ ███ ████████ █████████ ██ █████ ██ █████ ████ ██ ████████████ ███ █████ ████ ███████████ ███████ ███████ █████████ █ ██████ █████
Summarize Argument: Phenomenon-Hypothesis
Scientists hypothesize that when a hornworm’s first meal is from a nightshade, its taste receptors become habituated to indioside D, and afterward anything without indioside D doesn’t taste good. This is based on the fact that newly hatched hornworms that first feed on nightshades don’t eat leaves from non-nightshades afterward, whereas newly hatched hornworms that first feed on non-nightshades are open to eating non-nightshades afterward.
Notable Assumptions
The author assumes that there isn’t another explanation for the observed diet patterns of hornworms. For example, what if there’s some other chemical besides indioside D that might be the reason hornworms that eat nightshades prefer nightshades and don’t eat non-nightshades? Or what if the hornworms don’t necessarily care about the taste of nightshades, but become physically addicted to it, without regard to taste?
6.
Which one of the following, ██ █████ ████ ███ ████ ███████ ███ ███ ███████████
a
Tobacco hornworms that █████ ███ ██ ██████████ ██████ ████ ██ ██████████ ███ ███ ███ ███████ ██ ██████████ █████ ████ ███ ██████
We’re concerned with the consumption of nightshades vs. non-nightshades. Preferences or the lack of preferences within the nightshades has no clear impact.
b
If taste receptors ███ ███████ ████ ███████ █████████ ████ █████ ███ ██ ██████████ ███████ █████ █████████ ████ ████████████ ████ ██ █████ ███████
This corroborates the theory that taste receptors are part of the explanation for the observed diet patterns.
Plausibility
Plausibility
Presenting evidence that corroborates (in Strengthen) or conflicts (in Weaken) with the author's hypothesized explanation or the predictions that follow from that explanation.
c
Tobacco hornworm eggs ███ ████ ████████ ████ ██ ██████████ ███████
Where the eggs are laid has no clear impact. We’re concerned with the diet patterns of newly hatched nightshades and what explains the distaste for non-nightshades among the worms that first feed on nightshades.
d
Indioside D is ███ ███ ████ ████████ ████ ██████ ████ ██ ██████████ ███████
This weakens the argument by suggesting there may be another chemical responsible for the worms’ preference for nightshades after first feeding on nightshades.
e
The taste receptors ██ ███ ███████ ████████ ████ █████████████ █████████ ██ ███████ █████████ █████████ ██████████
This doesn’t help connect taste receptors to habituation to nightshades or to the chemical indioside D. We also don’t know the significance of a “physiological reaction.” Does that mean the worms can taste chemicals? We don’t know.