Reading Comprehension

PT127 · S4 · P2 · Q9 Inclusive Fitness Theory

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Mechanisms for recognizing kin are found throughout the plant and animal kingdoms, regardless of an organism's social or mental complexity.

Topic

Why kin recognition exists among animals and how it can be explained by different evolutionary theories.

Framework

Answer / Explain

Main Point

Scientists have several explanations for why animals recognize their kin: inclusive fitness theory proposes it’s to protect their own genetic legacy by helping relatives, but in some cases (like with tiger salamanders), avoiding kin may purely be for self-preservation to reduce risk of disease. *The Most Valuable Sentence is probably the last sentence of P2: and the last sentence of P3: *

P1: Introduction to Inclusive Fitness Theory

All kinds of organisms can recognize their kin, and one important theory (inclusive fitness) says this happens so creatures can increase the survival of their own genes—not just through offspring, but through relatives, too. This theory helps explain behaviors that don’t seem to benefit an individual directly, like sterile worker bees helping their family.

P2: Applying Inclusive Fitness Theory to Cannibalism

This theory is supported by studies of cannibal tadpoles: they usually avoid eating their relatives, which makes sense if they’re trying to protect their own genetic legacy. Occasionally, ultra-hungry tadpoles will eat siblings anyway—implying that self-preservation can sometimes override this behavior.

P3: Alternative Explanation—Disease Avoidance

But inclusive fitness isn’t the only answer! For tiger salamander cannibals, avoiding kin may actually just be about not catching deadly diseases, since they’re more likely to get sick from eating relatives. For them, kin recognition may not be about helping family, just avoiding illness and preserving their own life.

9.

The passage states which one of the following about some spadefoot toad tadpoles?

  1. They develop the ability to

    Bad Match

    The cannibals learn to recognize siblings, not fellow carnivores. The passage says they nip other tadpoles and release siblings; it never says they can tell which tadpoles are also cannibals.

    2% picked this

  2. They feed only upon omnivorous

    Contradicted

    Carnivorous tadpoles feast "on other animals including members of its own species," and the trigger can be eating a freshwater shrimp. Their diet is not limited to omnivorous tadpoles.

    1% picked this

  3. Correct

    They change in body size

    Why this is right

    The second paragraph says eating another tadpole or a shrimp can trigger changes in physiology, "causing the tadpole to become larger and exclusively carnivorous."

    Skill tested: Locate Detail · how this choice captures the passage's function is the move to repeat next time.

    87% picked this

  4. Their carnivorousness constitutes an important

    Opposite

    The tadpoles' kin-sparing cannibalism is offered as support for inclusive fitness theory. The passage says it "suggests that the inclusive fitness theory offers at least a partial answer," not that it calls the theory into question.

    6% picked this

  5. Their carnivorousness would not occur

    Too Strong

    The passage never states that carnivorousness could not exist without an evolutionary payoff. It uses the tadpoles to illustrate kin recognition under inclusive fitness theory, and it stops well short of this sweeping conditional claim. Inclusive fitness theory isn't saying, "traits only develop if they benefit the species as a whole". It's saying, "traits can develop because, even though they don't benefit the individual's survival, they benefit the survival of an organism that shares most of the individual's genes (i.e. a relative)."

    4% picked this

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