CIE A2 Paper 42 Biology - May 9th

What did ya'll write for which field would have more inverterbrates, and the one about mark-release-recapture's validity

Reply 21

tuckerthetatman

1

Grazed field because there will be less birds predating the invertebrates. For the validity I wrote allow time for the population to mix and capture the animals in a random area within the field to avoid any bias.

Reply 22

TerraformingYou

1

The thing about the prediction was that birds fed on the invertebrates, but invertebrates fed on the seed.. I don't know if this is correct, but won't invertebrates be unable to eat the seed if grassland was grazed? I was confused what to write haha

I wonder if just saying "random sampling" would be good for the results of the mark-release-recapture to be reliable..

Reply 23

sara_od

9

I couldn't think of anything for the validity one, so I wrote make sure the marking can't fall off and make sure any phenotypic variations aren't mistaken for a different species.
I wrote grazed had more inverterbrates because of predation by birds, too

Reply 24

Dohaeris

OP

3

For validity, I wrote that none of the animals should be marked in such a way that it affects their chances of survival, and there must be no migration of the animals being studied either into or out of the grasslands.

And I wrote ungrazed, because then there would be no herbivores feeding on the plant material (as stated in the question) and so there would be more seeds available for the invertebrates. Am I alone here?

All in all, the paper wasn't difficult. Pretty good

Reply 25

SamihaTahsin

3

i picked ungrazed cause seeds grow better there so the invertebrates have a larger source of food

Reply 26

SamihaTahsin

3

Original post by Dohaeris

For validity, I wrote that none of the animals should be marked in such a way that it affects their chances of survival, and there must be no migration of the animals being studied either into or out of the grasslands.

And I wrote ungrazed, because then there would be no herbivores feeding on the plant material (as stated in the question) and so there would be more seeds available for the invertebrates. Am I alone here?

All in all, the paper wasn't difficult. Pretty good

for the validity question, my first point was something like the marker used should be such that it's not harmful to the invertebrate, otherwise it might die. it's a little modified, but is it ok?

(edited 7 years ago)

Reply 27

A.S.J

2

HI.
I did chem and bio both.
For biology I thought it was an okay paper but was definitely surprised at no Muscles and not enough genetic technology. I also did q9. But because part A was 6 marks I only mentioned aerobic respiration. I did a similar question before and the examiners mark for every small thing.
I was shocked at the Krebs cycle marks though.
So i started from the link reaction to krebs cycle and the products and said that the products go to oxidative phosphorylation.
Over all it was okay althought people said it was hard.

Chemistry was a pain!!! What was that thing??? Im so shocked! I mean im so scared now. Such a weird paper!
Im praying the gt goes to as low as 45 for an A!

Paper 5 today was okay too. For the 8 mark qstn i described that we could use a quadret at a known area for both fields and described what to keep constant.
For the invertibrates i wrote that they should be taken and released in the same area.
They should be markes in a way thay it doesnt effect them and that they should be left for enough time to breed.

I chose ungrazed because then the plants have enough time to mature

The smoking one? PEFR the variables,
I wrote the volunteera should be all of same age
From the same environment
Same number of volunteers

The null hypothesis
I wrote that the original PEFR value for all volunteers had no significanct different
What about ou all?

Anyone do physics AL here??

Reply 28

Munii

1

So, I made a realllyyyyy careless mistake today. You know that part with the Simpson's rank correlation? I didn't "1 -" to get the rs. I honestly did not see it in the formula, I don't know how I missed it. Do you think there's be an ecf for the questions relating to it??

Reply 29

Dohaeris

OP

3

Original post by Munii

So, I made a realllyyyyy careless mistake today. You know that part with the Simpson's rank correlation? I didn't "1 -" to get the rs. I honestly did not see it in the formula, I don't know how I missed it. Do you think there's be an ecf for the questions relating to it??

You didn't do variant 52, did you? We didn't have a question about spearman's rank correlation on our paper.

Reply 30

Munii

1

Original post by Dohaeris

You didn't do variant 52, did you? We didn't have a question about spearman's rank correlation on our paper.

I did 51 ... :/ was hoping at least one person here did the same :frown:

Reply 31

A.S.J

2

Original post by Munii

So, I made a realllyyyyy careless mistake today. You know that part with the Simpson's rank correlation? I didn't "1 -" to get the rs. I honestly did not see it in the formula, I don't know how I missed it. Do you think there's be an ecf for the questions relating to it??

Original post by Munii

I did 51 ... :/ was hoping at least one person here did the same :frown:

Was it a lot different then 52?
If it has other parts then yes, ecf. :smile:

Reply 32

Munii

1

Original post by A.S.J

Was it a lot different then 52?
If it has other parts then yes, ecf. :smile:

Thanks so much! I feel so much better now...
I dont think it was thatttt different. Question 1 was to investigate if the distance of plants from a pond's edge influenced their species abundance and distribution. We had to write and describe our method, answer statistics related questions about soil investigations. Question 2 was about nicotine addiction and a rat experiment to reduce it basically...

Reply 33

Coolmeechy

3

Original post by tuckerthetatman

It wasn't too difficult except for that 8 marker, didn't revise much on the diversity index

same here..It wasnt difficult but i hadnt revised tht portion. :s-smilie:

Hope my made up answer hav atleast a few points from the markscheme.

Reply 34

A.S.J

2

Original post by Munii

Thanks so much! I feel so much better now...
I dont think it was thatttt different. Question 1 was to investigate if the distance of plants from a pond's edge influenced their species abundance and distribution. We had to write and describe our method, answer statistics related questions about soil investigations. Question 2 was about nicotine addiction and a rat experiment to reduce it basically...

The first one for us was to describe any method that would help us know about biodiversity. I said to use quadrats
The second one was PERF and smoking

Reply 35

Coolmeechy

3

Original post by tuckerthetatman

Grazed field because there will be less birds predating the invertebrates. For the validity I wrote allow time for the population to mix and capture the animals in a random area within the field to avoid any bias.

Original post by sara_od

I couldn't think of anything for the validity one, so I wrote make sure the marking can't fall off and make sure any phenotypic variations aren't mistaken for a different species.
I wrote grazed had more inverterbrates because of predation by birds, too

I am actually confused...How would a grazed field have less birds predation?..

Reply 36

TerraformingYou

1

Original post by Coolmeechy

I am actually confused...How would a grazed field have less birds predation?..

That's what I found so confusing.. The argument for the grazed area is that if the area is grazed, probably less birds would be there to predate on the invertebrates..

That being said, I answered ungrazed because ungrazed areas would probably have more seeds for the invertebrates to eat on, resulting in less competition for food and their populations to increase (but at the same time this may cause more birds to lie within the area, but I felt like answering ungrazed overall made more sense)..

Reply 37

sara_od

9

Original post by TerraformingYou

That's what I found so confusing.. The argument for the grazed area is that if the area is grazed, probably less birds would be there to predate on the invertebrates..

That being said, I answered ungrazed because ungrazed areas would probably have more seeds for the invertebrates to eat on, resulting in less competition for food and their populations to increase (but at the same time this may cause more birds to lie within the area, but I felt like answering ungrazed overall made more sense)..

Brids trying to feed in the grazed field will have competition from the herbivores so they're more likely to eat from the ungrazed field. Less birds in the grazed field means more inverterbrates.
Plus, the herbivores that eat the growing plants poop out the seeds, they wouldn't be competing with the inverterbrates. The grazed would actually have more seeds because grazing increases pollination and the creation of seeds
But it's over so it doesn't really matter anymore lol
Good luck with your results and other exams!

Reply 38

Coolmeechy

3

Original post by TerraformingYou

That's what I found so confusing.. The argument for the grazed area is that if the area is grazed, probably less birds would be there to predate on the invertebrates..
That being said, I answered ungrazed because ungrazed areas would probably have more seeds for the invertebrates to eat on, resulting in less competition for food and their populations to increase (but at the same time this may cause more birds to lie within the area, but I felt like answering ungrazed overall made more sense)..

Yea.. I answered ungrazed too with similar reasons. I am guessing its not a yes or no answer. Both are probably right and depend on the justification we gave...

Reply 39

TerraformingYou

1

Original post by Coolmeechy

Yea.. I answered ungrazed too with similar reasons. I am guessing its not a yes or no answer. Both are probably right and depend on the justification we gave...

Fingers crossed for good reasoning xD

CIE A2 Paper 42 Biology - May 9th

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