STAV 2010 queries

[VCAA Official]

1. Why can't MC question 22 be A?
2. Can you explain the answer to question 9 of the MC as well as question 6?
3. Why is the answer to 1c of the SA so?
4. What do you think of my answer to the last question on the paper? how many marks would you give me, why is it wrong (it's different to the solutions at least), i feel like it's equal to the solutions but along a different path I don't know. Q7g. my answer: they are nto our ancestors and we lived in seperate groups (travelled indepedantly).

Thank you.

[happyhappyland]

why dont u type the question up

[herzy]

put the questions up and i'll have a look!

[VCAA Official]

MC22: In 1975 a strain of a acteria was dicovered living in waste water coming from a facoty producing nylon. theis bacterium was able to break down the nylon molecule. nylon is a manmade fabric that was devveloped in 1936. it would be reasonable to state that:

*my answer a* the gene goerning nylon renakdown alwys existed in these bacteria but was only discobered in 1975
*correct answer b*: there was a mutation in these bacteria enabling them to be able to break down nylon

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last question on the paper:

the denisova homonin differs from modern hunan DNA bby 385 nucleotide bases out of a possible 16500 whereas neanderthals differ by 202 nucleotide bases. anthorpologists believe that homonin left Africa in wasves of migration firsty erectus aout 1.9 mill years ago then neanderthals between 300,000 to 500,000 years ago then finally sapiens around 70,000ya. what does the mtDNA evidence suggest aout the relationship between sapiiers, denisova homonin and their migratin out of africa

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dont' worry about the other questions I mentioned, they are too long to type out

thanks

[herzy]

um mc b) makes more sense, because a gene which is being expressed for something (e.g. nylon breakdown) which is usually useless wouldn't be a selective advantage. a mutation would need to arise, and then it would become a selective advantage. don't worry about it too much tho its a little badly worded.

second q, basically denisova migrated earlier than neanderthalensis, because they are less closely related to sapiens... greater the difference in base sequence, the greater the time since they branched off.

[stonecold]

Another awful exam.

Question 17.  Which of the following is not an example of direct evidence to support evolution.

Answer Fossils.

WTF!!!!!

Other alternatives were:
-resistance of bacteria to antibiotics
-increased pesticide resistance in insects
-observed allele frequency changes in polulations.

More to come...

[stonecold]

For 9, they say C...

[herzy]

umm that question can be explained because each of the other answers display *adaptation* which is, of course, integral to evolution. read any book on creationism, and they'll tell you how fossils are not proof of evolution. rather, fossils support other evidence (creationists: 'so-called evidence')

it's a valid question - i can understand how its confusing, but also make sure you read all the other answers carefully - fossils should have been the odd one out

hit us up wtih more!

btw, definitely not creationist. but because i am so pro-evolution, i agreed to read 'refuting evolution' as part of my attempt at open-mindedness for a friend

[herzy]

For 9, they say C...

look at your answer for q 8: Cri du Chat is dominant, and half of the woman's gametes are affected (dominant). in essense, she is Aa (or Cc)

if the man is cc, then offspring would be Cc, Cc, cc, cc = 50%

[stonecold]

umm that question can be explained because each of the other answers display *adaptation* which is, of course, integral to evolution. read any book on creationism, and they'll tell you how fossils are not proof of evolution. rather, fossils support other evidence (creationists: 'so-called evidence')

it's a valid question - i can understand how its confusing, but also make sure you read all the other answers carefully - fossils should have been the odd one out

hit us up wtih more!

btw, definitely not creationist. but because i am so pro-evolution, i agreed to read 'refuting evolution' as part of my attempt at open-mindedness for a friend

I think aspects of evolution are stupid.  I no it is considered WRONG, and I wouldn't do this in the exam, but matuation seriously has more to do with it than is made out IMO.  The alleles within a population surely could not be enough to create a new species.

Fair enough on the fossil question.  For Q9, they are trying to flog off 25%...

Also, this question, the restriction sites IMO are screwed.  I don't get what to do for part d.

[herzy]

what do you been by matuation? and the key to evolution is time: we can prove that changes occur in species in the course of a few generations as a result of intense selection and allelic variation, so if you extend that multiple times over millions of years, with little gene flow/inter breeding, speciation is kinda plausible (IMO )

[herzy]

the key to question d (and its a stupid question, some of my students came to me with it - they made a typo!) is your answer to question c. you're right, they screwed up, but what they wanted was for you to say that in full SSA no cutting would occur (homozygous for 1.4), in heterozygotes you'd have 1.4, 1.2 and 0.2 and in homozygous normal you'd have 1.2 and 0.2 (1.4 being at the top of the page, 0.2 being at the bottom)

hope you get the theory, even though the question was terrible

[stonecold]

what do you been by matuation? and the key to evolution is time: we can prove that changes occur in species in the course of a few generations as a result of intense selection and allelic variation, so if you extend that multiple times over millions of years, with little gene flow/inter breeding, speciation is kinda plausible (IMO )

It is probably VCE biology which has screwed my logic.  In reality, most traits are polygenic, so I guess if you accumulated the right alleles, you would see a significantly different phenotype.

It is just that in VCE, most things are monogenic traits so you don't get continuous variation.

Speciation depends on continuous variation, so it would be a lot more complex as you have suggested.

[stonecold]

the key to question d (and its a stupid question, some of my students came to me with it - they made a typo!) is your answer to question c. you're right, they screwed up, but what they wanted was for you to say that in full SSA no cutting would occur (homozygous for 1.4), in heterozygotes you'd have 1.4, 1.2 and 0.2 and in homozygous normal you'd have 1.2 and 0.2 (1.4 being at the top of the page, 0.2 being at the bottom)

hope you get the theory, even though the question was terrible

I don't get the cutting or even the size of the DNA bit.  Did I draw in the cutting sites wrong?

[herzy]

normally the restriction site is CCTGAGG, and when the whole gene is cut, you get two pieces of 1.2 and 0.2. When the mutation occurs, first G goes to T, so restriction site cannot restrict, and so the gene isnt cut, leaving one whole gene of 1.4