Your Thoughts On Biology 2010 Exam 2

[stonecold]

I said that the overlap zone may have changes in allele frequencies but that the upper region would stay relatively similar so long as there were no changes in selection pressures. I hope they reward good biological thinking for this question.

yeah, the fact that they were different populations seems to indicate that there wouldn't have been gene flow between the two...

[masonnnn]

yeah i also said they'd remain consistent as to their current selection pressures as there was likely to be no gene flow and the crabs couldn't even reach the northern area so the areas were most likely isolated so, seperate populations.

[onerealsmartass]

so what were the other dodgy questions apart from; the jaws, centromere and fisherman??
multiple choice was fairly straight forward not many tricks in that.

[stonecold]

index fossil q was D

[onerealsmartass]

cant quite remember what the question was... but i remember a fair few D's

[sillysmile]

so are you guys suer that the other jaw was from a gorilla and not a chimp?

[onerealsmartass]

im 100% sure, cos when i was raeding the question i thought arent chimps jaws rectangular?
but reread it and it said gorillas, so i thought that gorrilas and chimps share a mroe common ancestor so they will have rectangular jaws? dont know if my line of thinking was right but yeah it was between australopithecus and a gorilla

[Stroodle]

Yeah I just wrote that the gorillas jaw was more rectangular, and that it had larger canines.

[thushan]

yeah i also said they'd remain consistent as to their current selection pressures as there was likely to be no gene flow and the crabs couldn't even reach the northern area so the areas were most likely isolated so, seperate populations.

At first I said that the average shell thickness was constant due to lack of selection pressures, but then changed to:

Average shell thickness would increase as gene flow would occur between the two populations as there is no geographical barrier: the stem of the question said to assume that the crabs cannot migrate to the other population so that students don't talk about selection pressures in the north resulting in increase in shell thickness. Btw just because there are two distinct populations does not mean that gene flow - migration and interbreeding - cannot occur.

But I agree; odd question...we'll have to see what the assessors will pay

[cypriottiger]

yea i said no change in shell thickness, because they do define the two popluations as being "northorn blue mussel"and "southen blue mussle"...
doesnt that imply they cant interbreed? did the question state they were two species?

[itsMRPHI]

I thought it was an example of co evolution :S

[pi]

the question was a bit ambiguous, lots of different interpretations

[thushan]

true that...I interpreted it as two populations of same species where gene flow can occur

[Stroodle]

I also said that gene flow could occur. Wouldn't be surprised if they'll accept either way on this one, as long as you back it up in the way they want you to..

[s2lindah]

Hi everyone
What did you guys write for the man with the translocated segments of chromosomes and how he was phenotypically normal?
I wrote something like the genes that were translocated were also found on other chromosomes so that he was not lacking the expression of any gene.