*SAT Subject Test Biology E/M June 2016 Discussion Thread*

@WinnerWannabe i think it will be better than the ones in the past since this one was fairly difficult

Yeah it must have been chemical because the synapse is a chemical signal

What did you guys get for the insect one because everyone is disagreeing on that answer

Guys was the muscle signal electrical or chemical

Which question was the insect one?

@neehal120

The muscle signal was chemical; I’m 100% positive. The specific neurotransmitter is acetylcholine, which PR mentioned.

@WinnerWannabe That one was #11, where it asked you to match one of the population size graphs to the description, “the population of insects around a tree after it falls until it is finally decomposed.”

@neehal120 I said C, the bell curve. I’ve heard people argue A, the exponential increase, but given that nutrients and space decrease as the tree decomposes, I find C to be more logical.

I’ve also heard people say D, the linear decrease, while arguing that the insects aren’t necessarily the decomposers; however, I think it’s implied here.

Ok! I think I put the bell curve because the population will increase within the tree when it initially falls and will decrease as the tree decomposes.

@mastersuperfan but the question stated that the tree fell and began to decompose therefore you could also infer that because the tree died after falling it was decomposing, therefore the population of insects living in the tree would die as time increased because less and less of the tree would remain to provide them with a habitat

@neehal120 Yes, but the tree wasn’t completely swarmed by insects right away. After it fell, some insects came to decompose it, and over time they reproduced to increase the population.

Too bad college board doesn’t release the exam with the answers after testing…

@mastersuperfan but then why would they decrease if they were the decomposes of the plant

Also do you guys think it will be minus 3 or 4 for an 800

@neehal120 As the decomposition continues, the amount of space and nutrients decreases, limiting the number of insects that can continue decomposing the tree. Thus, not all insects will be able to stay, and some will leave. It’s as if the tree has its own carrying capacity. The insect population starts out small and grows exponentially until it hits the carrying capacity; simultaneously, the carrying capacity is constantly decreasing until the tree has finished decomposing.

@mastersuperfan By that logic then as they decompose then their habitat is also decreasing which will result in many dead and the insects are reproducing therefore it should be no growth at the beginning and then decreasing growth as time increases

@neehal120 No, because the tree isn’t completely swarmed with insects yet. It’s not like the tree is already surrounded by insects ready to decompose it before it even falls. Some insects come over to the tree first, and they reproduce at the tree to increase the population size exponentially before they hit the carrying capacity.

@mastersuperfan but I am saying that the insects lived in the tree therefore they should have been right next to the tree to decompose otherwise the question should have stated that the insects began to decompose the tree after X number of minutes

@neehal120 How would we able to assume that enough insects lived inside the tree to completely cover it after it fell?

And Arthropoda cannot decompose the tree itself they can only decompose the leaves from the tree therefore it would be more reasonable to assume that they lived in the tree and when the tree fell the bark was decomposes by fungi or bacteria

hey. Did anyone take the test today? does it have the same curve as the one from yesterday