BIOL4 Biology Unit 4 Exam - 13th June 2011

Yep. I'm so pissed off that all this completely irrelevant Ecology crap is what will get me into university to study Pharmacology. It is so annoying. I wish we got to choose modules or something for the A Level.

Finally starting to feel more confident about this exam. Ive been doing lots of revision, its just silly application questions. Like, i get the process of respiration and photosynthesis but its the ones where they apply it to something, and i just have NO clue what theyre going on about.

Every other topic in this module im VERY confident with, but with respiration and photosynthesis im REALLY struggling - probably because its alot of biochemistry which i SUCK at. Theyre probably going to be on this paper too, since they wernt in January.

for percentage cover you use quadrats again, but you grid the quadrats using string or something like that. you then randomise it by using coordinates again. however, this time you count how many plants (that your investigating) are in the whole quadrat. so if the plant your investigating covers 5/10 squares within the quadrat then thats 50% obviously. if one square is covered only half then you still count it. then you work out the average as before....

Doesnt let me rep u!


The area of soil was left for five years. During this time, the index of diversity fell to 3.75. Suggest an explanation for this fall. (4 marks)

not sure how this question is to do with succession since succession increases the biodiversity

whats the whole question, like any previous parts to it that might be useful as this seems strange...?

Its a long question

Its Q7 part (v)

AQA BYA 5- JUne 2007


Am really struggling with these Q below:
• 7b (v)---> not sure how this question is to do with succession since succession increases the biodiversity
• q8aii--> the answer is wrong in all measures ( or am being thick)
• 6a-6ciii (last part glucose?!)
• 8b ???
•
Anyone feel free to answer ( +rep)

can you link me to the paper please ...

7b - to be honest, this is tough but i think its to do with animals coming into the area and actually restricting succession.

Initially, the area has become diverse in plants due to 1 year of succession occurring. However, animals colonise the area because there is plenty of vegetation to feed on, so they survive and successfully reproduce. Over time this leads to an increase in the numbers of animals in the area, however the growth of new vegetation is not sufficient enough to support the increase in new organisms. Therefore species diversity is decreased due to these organisms feeding on the remaining vegetation in the area.

dunno if this is right but its an educated guess? lol.


8aii) yeh just leave out the big C and think of only the small letters above.

So, ‘c’ allele for ‘carbonaria’ is dominant to ‘i’ allele for ‘insularia’ which is dominant over ‘t’ allele for ‘typica’ .....

so if we have 2 carbonaria moths with codes of Ci Ci, there is a possibility of ‘ii’ being formed which would be ‘insularia’ in homozygous form. then say we have 2 moths of Ct Ct - there is a chance of them forming ‘tt’ offspring, which would code for ‘typica’ in homozygous form. but either of the above 2 codes (Ci Ci and Ct Ct) can code for CC,Ci or Ct as the offspring which would be ‘carbonaria’ again as 'C' is dominant over 'i' and 't' ..... hope this is clear haha...


I will try and answer the other two tomorrow im tireddd now haha.... hope this helps anyway. what does the markscheme say?

MARK SCHEME

Just had a quick look at your answers..its slightly different to ms ! But then again am not testing your knowledge !:P but would like to know

how to interpret ms

So for 8aii:

CiCi doesnt give a phenotype of carbonaria

There is no way u cross 2 carbonaria and get both offspring: ctct and cict
At least one Cc must be present in genotype of each parent= so they are carbonaria
Each parent must have had at least one Ct to give CtCt= typica

MARK SCHEME

Just had a quick look at your answers..its slightly different to ms ! But then again am not testing your knowledge !:P but would like to know

how to interpret ms

So for 8aii:

CiCi doesnt give a phoenotype of carbonaria

There is no way u cross 2 carbonaria and get both offspring: ctct and cict
At least one Cc must be present in genotype of each parent= so they are carbonaria
Each parent must have had at least one Ct to give CtCt= typica

edit: sorry just got you..... yeh the big 'C' i wrote before was just highlighting that they are dominant. imagine those to be the little 'c' sorry .... thats what i meantttt


so C^c C^i , C^c C^i .....for the parents is what i actually meant.

True but that doesnt give the third phenotype which is C t C i or C t C t

can someone explain how do you calculate the population in JAN 2011 paper 1 c ii?

basically, you have the total population 'per million' so you need to convert it to 'per 1000' as birth and death rate are 'per 1000':
107 x 1000 = 107000

next you subtract the death rate from birth rate:
20 - 5 = 15 (alternately you can convert these to 'per million' i.e. 20 - 5 = 15, 15/1000 = 0.015)

finally you multiply 15 and 107000 to get 1605000 (this is how many people the population will increase by) and add this to the original population:
107000000 + 1605000 = 108605000

hope this helped

oh thanks !

whatdid you get last time? or are you not resitting this paper?

ye i am resitting the paper, i got a solid D last time

how about u?