2009 exam help!

[radl223]

Hey guys, sorry for the lame question, but I've been having trouble with one particular question in the 2009 Unit 4 Biol exam.

Multiple Choice, Q7.
In pigs, the number of teats and litter size are under genetic control. Each piglet must have ready access to a teat.
British breeds of female pigs (called sows) generally have 12 teats and 11 piglets each litter. Some of the traditional British breed of pigs have been crossed with the Chinese Meisham pig. Chinese Meisham sows have up to 18 teats and average 16 piglets each litter. This crossbreeding has produced a hybrid pig called the Manor Meisham.

With respect to these breeding experiments, it is most likely that:
A. British farmers wanted to produce smaller-sized litters.
B.Chinese farmers wanted to produce larger-sized litters.
C. British sows were mated with Meisham males.
D. Meisham sows were mated with British males.

The answer is D, and the explanation was:

The Meisham sows, when crossbred with British males, would be able to accommodate the litter of the hybrid offspring comfortably as they have 18 teats. If the converse mating occurred there may be far more offspring than teats.

After reading the explanation, I still don't understand it Is this question just a matter of common sense? Any ideas or better explanations?

Thankyou, much appreciated!

[curry_bro]

well, A and B are both wrong because the hybrids wont serve this function.  In my opinion, either C or D could be right... i got this quesiton wrong too, i chose C and i still dont get why.

[Scooby]

Yeah, there's not really any background knowledge you need. It's just that because the Meisham sows have a greater number of teats than the British sows, they can accommodate a larger number of offspring, which I guess is beneficial for the farmer.

If you crossed a British sow and a Meisham male, you're not going to get that large number of offspring that the farmer wants, or you're going to have too many offspring for the British sow to accommodate, since she doesn't have enough teats

[spherelin]

Hey guys, sorry for the lame question, but I've been having trouble with one particular question in the 2009 Unit 4 Biol exam.

Multiple Choice, Q7.
In pigs, the number of teats and litter size are under genetic control. Each piglet must have ready access to a teat.
British breeds of female pigs (called sows) generally have 12 teats and 11 piglets each litter. Some of the traditional British breed of pigs have been crossed with the Chinese Meisham pig. Chinese Meisham sows have up to 18 teats and average 16 piglets each litter. This crossbreeding has produced a hybrid pig called the Manor Meisham.

With respect to these breeding experiments, it is most likely that:
A. British farmers wanted to produce smaller-sized litters.
B.Chinese farmers wanted to produce larger-sized litters.
C. British sows were mated with Meisham males.
D. Meisham sows were mated with British males.

The answer is D, and the explanation was:

The Meisham sows, when crossbred with British males, would be able to accommodate the litter of the hybrid offspring comfortably as they have 18 teats. If the converse mating occurred there may be far more offspring than teats.

After reading the explanation, I still don't understand it Is this question just a matter of common sense? Any ideas or better explanations?

Thankyou, much appreciated!

I circled C. The question was more common sense and thinking about what would be most efficient/best for the offspring. I hate these questions HAHAHA

[slothpomba]

Thats kind of a shitty question...is it VCAA?

A) Doesn't make sense since this breed would produce *larger*, not smaller as the answer suggests, litters.

B) The chinese pigs already had a high number of teats and offspring, again, makes no sense.

C) Sow = Female/Chick pigs. To cut to the chase, most men lack tits. Male pigs don't (why would they need to?) have teats. We want the high teat number from meisham/chinese pigs. It doesn't make sense to breed a male chinese pig and a female british pig, since teat genes are obviously related to being female. Thus its best to...

D) Breed a female chinese pig (since the teat genes are related to female pigs and the pig with more teats is the chinese pig) with a male english pig..

My logic doesn't seem to match theirs all that much though. It really depends what makes the genes expressed and if they're linked to a sex chromosome. Probably reading too much into it though.