The Biological Question Thread

[Jdog]

yeah cool thanks, apparrently, theres a differentiation now betweeen australopithecus species, they've introduced a new one calle paranthropus, of which there is no mention in Nature of BIo. Just read that ammendment . VCAA released a paper on this topic recently ifanyone's interested just google it.

[lexitu]

IF PLANNING TO DO THE AUSTED EXAM AND DON'T LIKE SEEING QUESTIONS DON'T READ THIS.




The answers list B and A respectively. However, although it is more likely to be X-linked (not directed to answer for the most likely in question) D and C are also correct. Can someone please confirm this and or point out some obvious mistake that I made? Thanks.


Also, what would your answer for this be and please tell me that these are stupid options:

Question 22

Fossils in the genus Australopithecus are thought to represent branches on the tree of life intermediate between apes and humans because:

A.   They show many features that are intermediate between apes and humans
B.   They show a mixture of the features of apes and humans

Cheers.

EDIT 3: THE F##K'S SAKE EDITION

Also these questions which are not good at all. I'm getting angry at the answers. So before I disclose them I want to know what people would say:


The forelimbs of birds and bats are:
 
A.   Homologous
B.   Convergent
C.   Analogous
D.   Both analogous and convergent

Question 24

Which of the following does not come under the category of genetic drift?
 
A.   The founder effect
B.   The bottleneck effect
C.   Sexual recombination
D.   Gene flow   

[Russ]

Your photo isn't loading, switch it from google hosting to a proper photohost (tinypic or imageshack etc.) and I'll answer that.
For 23, the forelimbs are analogous structures but examples of convergent evolution, which suggests D. Depending on how literal the question is, it could conceivably be C.

For 24...I really need to go check if gene flow is part of drift or independent of it, but I'm thinking C

[lexitu]

Thanks Russ.

Ahh yeah will do right now, thought it worked because it was displaying for me.

I agree with you Russ. I put analogous and convergent and they had homologous which is clearly wrong considering they are of different classes. Besides are we expected to know that bats are mammals and birds aves?

Also, for 24, they have the answer as D but I am 98% sure it is recombination (which can clearly result in drift because of its randomness).

Don't know if you missed it, but how about 22?

[Russ]

I see no way in which they're homologous, I agree that A is wrong unless I'm missing something pretty major. Can't speak for whether or not you need to know it, but the birds/bats thing is a pretty typical example so I suspect it might be on the design somewhere.

In that case I'll actually go find last semester's notes (not doing population genetics again till next year). It's possible that since recombination is a random event, that classifies it as drift...bit of a sneaky question if so.

I skipped 22, the two options confused me since I was taught that either would be suitable. Maybe someone else can help with that.

For the pedigree: even though the question doesn't specifically say that you have to nominate the most likely, you always do. When answering pedigree questions, it's always theoretically possible that a trait that skips a generation could be dominant (eg spontaneous mutation arose). Because of stuff like that, you're always working out which mode of inheritance is most likely.

Assuming you meant q8, C is incorrect, it can't be X-dominant or I-4 would need to be affected. D is plausible, but less likely due to the 2:1 ratio of men:women affected.

[lexitu]

Yeah I agree 100%. They are wrong.

I was also thinking that either could be correct for Q22 so don't worry about it.

For the pedigree I definitely agree that I should have circled sex-linked (I somehow disproved it, in the timed exam), but I trust VCAA to have a pedigree with only one inheritance mode or make it clear that there may be a more likely option in the exam.

Yeah for Q8 C is definitely incorrect.

As always the study designs are ambiguous as ever so it's hard to know exactly what they want of us, although it's my opinion that specific examples are usually not needed for VCAA exams because enough information is always present in the stem of the question.

There are even more errors going through the answers, but I won't bother you with them. Thanks for your efforts anyway, always appreciate your readiness to help:

And to anyone wanting to do this exam - don't do it; it sucks.

[stonecold]

These are from LisaChem 2007.  Not too sure of their answers.

[stonecold]

...

[lexitu]

Here are the answers

Unless you thought the answers were wrong?

[stonecold]

yeah, i thought they might be wrong :S

[Wally]

...

don't quote me but im pretty sure the answer for that one is d

[stonecold]

...

don't quote me but im pretty sure the answer for that one is d

They say A.  I personally thought that they were all wrong.

Wouldn't the genotypes be ABE abe ABe abE  ?

[lexitu]

Question 7 - I'm not sure about: I find that stuff very confusing.

But question 3, I am 100% sure that all answers are wrong.

EDIT: Haha, just noticed that I wrote "question 7" twice.

[Wally]

oh hang on yeah it would be A. i'm not gonna bother explaining it cause i will totally stuff it up but remember the "A/a" aren't swapped over and i think that's how you got your answer that you just wrote

they've also put the possibilities written in answer A in a different order to make it more confusing (logically the second and third combos should be switched around)

[stonecold]

How is A right?  Doesn't that represent crossing over which has occurred between alleles A/a and B/b ?