Passage Discussion

[jgmartin82]

DECEMBER 2012, SECTION I, PASSAGE 2

Passage 1

Paragraph 1 tells us about where plants get their characteristic smells and tastes. Apparently plants have two categories of substances. Primary for basic function and secondary, which has no known function but is responsible for the distinctive smells and tastes of plants. We get something as well about how the secondary substances vary plant to plant but are similar in closely related plants.

This feels like background, no real arguments being presented, let’s use it for context and keep our eyes peeled for an argument as we hit the second paragraph.

Paragraph 2 has a nice strong topic sentence. Apparently the insects played a role in the development in the secondary substances. We never seem to get an argument though, just description of how the insects played the role. The gist is that the plants randomly develop a substance through mutation, but will only pass that trait on if it helps them survive. This is basic evolution theory. Some substances attract friendly insects, some ward off or kill unfriendly insects. We don’t need to understand every word here, but it is important to know why it’s here and to do our best to get the gist of things.

Paragraph 3 gives us another helpful topic sentence. Apparently the insects and plants have evolved together. Insects eat plants; plants develop defenses; insects figure out a work around, and so on and so forth. We do bring it full circle back to the smell and taste; apparently the insects evolve those senses to figure which things they should eat and which they should avoid. Other consequences are listed as well as specifics about how the competition played out, but let’s not doddle, we’ll come back if we’re asked about it.

The Scale
So we got to the end of this thing without ever seeing a real argument. The author never gave much of an opinion, there didn’t seem to be much in the way of claims or counterclaims. What’s going on here? In fact, we’ve got one of those oddball LSAT passages that doesn’t present an argument. This was a strictly informative passage. It’s cool, it happens, nothing to panic about; just know they exist and roll with it when they appear.

Since we’ve got no argument, there’s no sense in imagining a scale. Instead, let’s get a simple sense of the major ideas we’ve got. Plants get their smell and taste from secondary substances, which aren’t essential to their function. These tastes and smells evolved in large part due to insects: we’re talking evolution people. The insects evolved along with the plants and that included their ability to smell and taste different plants.

A lot of that summary can be gleaned from the opening senses of paragraphs. It’s by no means a rule, but writers tend to clue you in to major points with the first part of their paragraphs. Use their clues to guide your read.