Logical Reasoning

PT150 · S2 · Q13 Scientist: It seems likely

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Scientist: It seems likely that the earliest dinosaurs to fly did so by gliding out of trees rather than, as some scientists think, by lifting off the ground from a running start.

Conclusion (seems likely that)

The earliest flying dinosaurs glided out of trees, rather than lifting off the ground from a running start.

Evidence

You can glide from a tree with very simple wings, and very simple wings are the middle evolutionary stage between "no wings" and the "large wings" we know the flying dinosaurs ultimately had.

Evaluate

The argument assumes a difference. Why does this lady think the first flying dinosaurs probably glided out of trees rather that lifting off the ground?

You can glide out of trees with simple "early-stage evolution" wings. She must be assuming that you can't lift off the ground to fly with simple "early-stage evolution" wings.

Goal

We need to find and eliminate four answers that add some plausibility to the idea that the first flying dinosaurs glided out of trees or detract some plausibility from the idea that the first flying dinosaurs did so by flapping they're very simple wings and lifting off from the ground.

13.

Each of the following, if true, strengthens the scientist's argument EXCEPT:

  1. Correct

    Early flying dinosaurs built their

    Why this is right

    If this answer can be said to have any impact, it is weaker than that of the other four. Ironically, almost all of us initially feel like, "Yup, (A) strengthens. I want to strengthen the idea that the first flying dinosaurs glided out of trees. (A) talks about dinosaurs and trees." But how does the fact that they built nests at the base of trees make it more plausible that they glided out of trees? Can they even climb up the trees? If they built their nests at the base of a tree, it seems like they couldn't climb the tree. No mama wants her nest all vulnerable at ground level. Nests are hidden and sheltered and protected to whatever extent the parents are capable of. If the nests were in the trees, that would strengthen. We could place dinosaurs at "the scene of the crime" ... i.e. in order to glide out of a tree, you need to be up in a tree in the first place. But this answer either suggests nothing about their ability to climb a tree, or suggests the opposite of what we want.

    Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

    74% picked this

  2. Early flying dinosaurs had sharp

    Strengthens

    This helps the plausibility of the "gliding out of trees" hypothesis by establishing that dinosaurs could feasibly climb up a tree, in order to have a launching spot from which to glide.

    3% picked this

  3. Early flying dinosaurs had unusual

    Strengthens

    This helps to give the "gliding out of trees" hypothesis a comparative advantage over the "lift off ground" one. It's saying that the first flying dinosaurs had feathers that were more conducive to gliding than to having any control during lift off.

    9% picked this

  4. Early flying dinosaurs had feathers

    Strengthens

    This hurts the plausibility of the "lifting off the ground" alternative hypothesis, by making it seem implausible that they could have run fast enough to take off.

    5% picked this

  5. Early flying dinosaurs lived at

    Strengthens

    This helps the plausibility of the "gliding out of trees" hypothesis by establishing that dinosaurs had an incentive to evolve adaptations that would allow them to climb up trees. Any dinosaurs whose mutations allowed them to climb trees would have great protection from the most dangerous predator in that dinosaurs habitat. A survival advantage like that would presumably be selected for by evolution. In other words, this answer increases the plausibility that dinosaurs could climb trees by pointing out a compelling selection pressure in the dinosaurs environment for tree-climbers.

    9% picked this

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