LSAT 136, Section 3, RC Passage 3, Animal Behavior

RC Passage 3 Explanation

PASSAGE TEXT: Traditional theories of animal behavior assert that animal conflict within a species is …

Paragraph Summaries

1. Traditional theories say animal conflicts within a species are usually ritualized and predictable. The Galápagos tortoise example shows this: the taller-looking tortoise wins through display, not serious fighting.
2. The spider A. aperta doesn’t fit that model because its fights vary a lot and can include biting and shoving. Riechert thinks evolutionary game theory explains this better because it treats fighting behavior as flexible depending on risks, rewards, and conditions.
3. Riechert predicts that spider fighting will change based on things like opponent size, danger from predators, and how easy it is to find another web site. Since good sites are scarcer in grasslands, grassland spiders should be more willing to escalate fights than riparian spiders.

Analysis

The passage is setting up a pretty simple contrast: old model = animals follow a fixed script; new model = animals adjust based on the situation.

The tortoises are used for the clean old-school example. But the spiders don’t fit it.

Evolutionary game theory is useful because it makes room for tradeoffs. A spider doesn’t need to “reason” like a human. The point is that, over evolutionary time, strategies that produce better reproductive success stick around. So “fight hard” can be a good strategy when the web site is valuable and alternatives are bad, but a terrible strategy when injury risk is high and another site is easy to find.

The grassland/riparian comparison is the test case. Grassland = fewer suitable web sites, so losing your spot is costly. Riparian = lots of suitable habitat, so why get into a full spider brawl if you can probably find another place?

For the questions, don’t let “game theory” distract you into human rational-choice stuff. The passage explicitly says evolutionary game theory is not about conscious reasoning. It’s about instinctive strategies measured by reproductive payoff.

TLDR: A. aperta fighting behavior is too variable for the old ritualized-conflict model, and evolutionary game theory gives a better way to explain and predict that variation.