Self-study
P1
The characteristic smell or taste of a plant, to insects as well as to humans, depends on its chemical composition. ███████ █████████ ██████ ███████ ███ ██████████ ██ ████████ ███████████ ███████ ███ ██████████ ███
Intro topic ·
Two kinds of chemicals in plants: primary and secondary
Chemicals determine smell and taste of plants to insects and humans.
Primary substances ·
Stuff required for growth and functioning; found in all plants
Secondary substances ·
No known role in growth/functioning; give plants distinctive tastes and smells
P2
███████ ██████ ██ ████ ██████ █ █████ ████ ██ ████ ███████ ██████ ███ █████████ ██████████ ████ ████ ██████ ███
Origin of secondary substances ·
Insects played major role
Causal mechanism 1 ·
Insects like some scents over others
Secondary substances result from mutations. Insects prefer some scents over others, which means the substances that produce those preferred scents are more likely to be passed on to future generations.
Causal mechanism 2 ·
Some substances produce stuff that helps defend against insects
Causal mechanism 3 ·
Some substances produce stuff that warns insects not to eat the plant
P3
███ ████████ ██ ████████ ██ █████ █████ ███ ████ ██ ████████████ ███████████ ███ █████████ ███████ ██████ ███ ████████████ ████████ ██ ███████ ███ ██ ███████ ██ ███ ██████ ████ ███ ███████ ████████ ███████ █████ ████ ████ ██████ ██ █████ █████ ██ ██████ ████ ██ ██████████ ███ ███████ █████████ ████ ███ ██████ █ ███ ██ ████████ █ ███████ ██████████ ██ █████ ██ ██ █████ ██████ ███ ██ ██████ ████ ██ ██ █████ ███ ███████ ██ ████ █████ ███████ ███████ ███████ ████ ██ ██████ ███ ██████ █████ ████████ ████ ███ ███████████ ███ ████ ██████████ ██████ ███ ███████ ██ ████████ ████ ██ █████ ██████████████ ███████ ██ ██████ ██ █████ ██ ███ ███████████ ███ ███████████ █████ ███ █████ ██████ ████ ████████ ██ ████████ ████ ███████ ███ ███ ███ ███████ ██ ███████ ███████ ██ ███████ ████ ████ ██████ ██ ██████ ██████████ ████ ████████ ███████ ███ █████ ███████████ ██████████ ██████ ██ ███████
Competition between insects and plants ·
Insects evolve to respond to plants' defenses
Might evolve way to detoxify plant's poison or store the poison in an unharmful way, for example. Might evolve way to identify poisonous plants.
Passage Style
Phenomenon-hypothesis (RC)
Single position
14.
Based on the passage, the ██████ █████ ██ ████ ██████ ██ █████ ████ █████ ███ ██ ███ █████████ ██████████ █████ ███ ████████████ ███████ ██████ ███ ████████
a
The diversity of █████████ ██████████ ████ ███████ ██ █ █████ ██████████ ██ ████████████ ██ ███ ██████ ██ ███████ ████ █████ ████ █████ ██████████ ███ ██████████ ██████████ ███ ████████████ ████████
Not supported, because we don’t know about any “proportional” relationship in plants and insects. The passage doesn’t suggest that the greater the number of insects interacted with, the more secondary substances a plant develops. For example, would a plant that has interacted with 10 species of insects have more secondary substances than a plant that has interacted with 9? We have no evidence of this relationship.
b
Although few species ██ ██████ ████ █████████ ████ ████████████ ███████████ ████ ████████ ████ ███████ ██ ███████ ███ ██████ ███████ ██████ ███████ ███ ██████ ██ ██████████ ███ ███████ ███████ ██ █████████
Not supported, because the author never suggests that only “few” species of plants have benefited from insects. We have no reason to think the proportion of plants that have benefited from insects of limited; it could be that all plants have benefited from insects.
c
Throughout the process ██ ████████████ ███████ ███ ██████ ██ █████ ███████ ██████ ████ ██████ ███ █████████ █████████ █████ ███ ██████ ██ ████████ ██ ██████ ███ ██████████
Not supported, because we have no evidence either that the number of species per family has gone up or that the number of families has gone down.
d
No particular secondary █████████ ███ ████████ ██ ██████ ██ ██████ ████████ ██ ████████ ██████ ██ ████ █████████ ███████ ████ ██████████ █████ ██████████ █████████ ██████████ ███ ███████ ██ █ █████ ████████
Supported, because we know that secondary substances appear
e
While many species ██ ███████ ████ ███████ ████ ██ █████████████ ███████ ████████ █████████ ████ ███ ████ ████ ███████ ████████ ████████ ██ ███████ █████████ ███████████
Not supported. We have no reason to think no insect has ever developed immunity to a secondary substance. The author never says she provides an exhaustive list of all potential defense mechanisms. So the fact she doesn’t mention immunity doesn’t imply that no insects have developed immunity.