<p>Well, burrow density didn’t really seem to be supported by the data; you had to extrapolate so much from it (I don’t even think that’s possible). The substrate made sense; it’s just that the word substrate itself is related to enzymes, and not generally used in this context that made it confusing.</p>
<p>i said substrate</p>
<p>for the crab and how you know they’re distinct species, i put like videotape their behaviours or whatever, because then you can observe if they interbreed or not, which would prove if they were distinct species or not. and I also said substrate, but i thought it was aerosol pesticides that contributed to acid rain? :S</p>
<p>I think by behaviours it meant like conditioning, habituation, etc. I thought it was aerosol pesticides, too, but apparently that’s wrong.</p>
<p>I thought the answer to the “can you tell if they are different species question” was through an observation of their morphology. Ultimately, analyzing DNA sequences would be an extremely difficult and at times usless mechanism for finding out if two species can produce viable offspring. THe most direct way to tell if they can produce offspring is thru an anaylsis of their morphology. Of course, video taping the craps behavior would have worked too…but the crabs lived in different locations and thus it would be hard to find out how the two species would interact if put together.</p>
<p>But meticulousness is not a factor for best identifying the species. The two could the same or nearly identical morphologies. In addition, videotaping would only indicate behavioral isolation or lack thereof, so it would not indicate if they could produce viable offspring. Only finite differences in DNA could accurately tell if they were different species.</p>
<p>i said DNA as well :/</p>
<p>I am not sure that temporal isolation could be identified with DNA analysis</p>
<p>Me neither, I’m pretty sure I wrote analyzing morphology.</p>
<p>Unfortunately, morphology is just fancy wording for “how it’s shaped”.</p>
<p>straight from wikipedia:
“A further problem with relying on morphological data is that what may appear, morphologically speaking, to be two distinct species, may in fact be shown by DNA analysis to be a single species.”</p>
<p>i dun think morphology would work then</p>
<p>Idk…I think there are problems with more morphological and dna analysis solely to determine this. That said, I bet that you guys are right…even tho I would argue that morphology is critical in determining if “mechanical isolation” exists in the prevention of two organisms from reproducing.</p>
<p>According to my old AP bio book (Campbell’s)</p>
<p>Mechanical isolation: Morphological differences that can prevent successful mating</p>
<p>Well, I think it’s almost understood that the crabs have similar morphologies…I mean it’s not like a crab and a giraffe.</p>
<p>I think the crux of that question was that the other choices show potential for types of isolation, but only DNA could prove that they were separate species or not. I personally was looking for offspring viability, but DNA was the closest choice.</p>
<p>@Tinks800: what book did you use??</p>
<p>I used Barrons and Princeton Review and i just read them over and over lol</p>
<p>for q 1-60, what did u guys get for the one w/ which of the following is a secondary consumer. I got it down to deer and spiders, and i put deers since they are herbivores…</p>
<p>i got rainforest for lush vegetation, deciduous for the cone-bearing trees, and i ommitted the last one</p>
<p>xShadow63- “Arthropods: Evolutionary Success”</p>
<p>why was it Arthropods for evolutionary success? I think i put humans, or manybe im thinking of a different question</p>
<p>also, in my barrons book the curve is a raw score of 61 is a 700, and more than 19 points wrong is in the 600s…</p>
<p>well…a few hours to go for results…all the best guys!!
do post your scores!!
<em>fingers crossed</em></p>
<p>If I don’t get 750+ I’m retaking in December for Regular Decision.</p>