#22 - A fourteen-year study of finches on the Galapagos

[James Finch]

Hi Whomer,

As this is a question about finches, I figured I should chime in

The big issue I think you're having here is focusing on conditional reasoning in the stimulus, when it's actually using causal reasoning chains, the use of the word "because" being the big giveaway here. What the confusing question stem is ultimately asking for is an answer choice that will eliminate a potential causal objection to the argument (alternate cause, reverse causation, cause w/o effect or vice versa) as a Defender Assumption. The correct answer choice here, (B), does that by eliminating a potential situation where a cause (abundance of large, hard seeds during a rainy period) could exist while its purported effect (greater numbers of large finches) doesn't, which would directly attack the argument's ultimate conclusion of climate being a cause for the population size of the different kinds of finches.

Hope this clears things up!

[whomer]

Thank you James!

[sseyedali]

Hi there,

I had initially selected (E), but I was flipping back and forth between (B) and (E). My reasoning for (E) was that the stim states: "The larger finch varieties have to consume enormous numbers of small seeds to meet their energy demands, and some just cannot eat them fast enough."

This quote led me to think that it doesn't matter whether large seeds are present or not, becuase in either case, big birds have to eat the smaller seeds for some reason, and they cannot eat them effectively. But, I now realize that this doesnt mean that they ONLY have to eat smaller seeds, and so some explaining needs to be done about what happens to larger seeds. Is that the deal breaker here?

I also thought (E) was attractive because it complemented well the difference in survival rates: when its dry, large finches > small finches because small finches cant eat the hard seeds. When its wet, large finches < small finches because large finches cannot eat the small seeds, while small finches can eat them easily.

Any more clarification on why (E) is less attractive than (B) would be really appreciated.

[Rachael Wilkenfeld]

Exactly sseyedali. Just because our stimulus tells us there are more small seeds, doesn't mean that the large seeds automatically disappear. More small seeds doesn't need to impact the large finches as long as the large seeds still are around to fill their bellies.

With answer choice (E), it's not clear what impact it would have on the argument. Let's say the small seeds did need cracked. We don't know how cracking shells would impact energy use/needs for large finches. It doesn't explain why they aren't eating the large seeds still. Cracking small seeds isn't clearly tied into survivability of those large finches. We already know they are too slow eating the small seeds. It doesn't matter if it's due to having to crack them carefully, pick them up one by one, or any other reason. It's not a requirement that the small seeds be able to be consumed uncracked.

Hope that helps!

[sseyedali]

Exactly sseyedali. Just because our stimulus tells us there are more small seeds, doesn't mean that the large seeds automatically disappear. More small seeds doesn't need to impact the large finches as long as the large seeds still are around to fill their bellies.

With answer choice (E), it's not clear what impact it would have on the argument. Let's say the small seeds did need cracked. We don't know how cracking shells would impact energy use/needs for large finches. It doesn't explain why they aren't eating the large seeds still. Cracking small seeds isn't clearly tied into survivability of those large finches. We already know they are too slow eating the small seeds. It doesn't matter if it's due to having to crack them carefully, pick them up one by one, or any other reason. It's not a requirement that the small seeds be able to be consumed uncracked.

Hope that helps!

Yes it does, thank you. I appreciate it!