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March 29, 2024, 10:37:02 am

Author Topic: VCE Biology Question Thread  (Read 3571071 times)  Share 

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Evolio

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Re: VCE Biology Question Thread
« Reply #11865 on: August 18, 2019, 11:30:33 am »
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Okay, thank you!
I looked at the notes you linked in your signature regarding the molecular clock principle.
With this principle, do you assume that there were 0 mutations at the time of divergence so that when you find the total number of mutations with the known mutation rate, you can figure out the time since they last diverged? Does this mean that there would be the same number of mutations having had occurred in both species?


darkz

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Re: VCE Biology Question Thread
« Reply #11866 on: August 18, 2019, 11:56:05 am »
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Okay, thank you!
I looked at the notes you linked in your signature regarding the molecular clock principle.
With this principle, do you assume that there were 0 mutations at the time of divergence so that when you find the total number of mutations with the known mutation rate, you can figure out the time since they last diverged? Does this mean that there would be the same number of mutations having had occurred in both species?

Yep, you'd assume that there are no differences at the time of divergence. Maybe in the ideal world, there would be the same number of mutations having occurred, but since you can have things like A -> T -> A, which you wouldn't be able to detect, it is all very theoretical.
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Chocolatemilkshake

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Re: VCE Biology Question Thread
« Reply #11867 on: August 18, 2019, 11:57:11 am »
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Are a selecting agent and a selection pressure the same thing or are they different?
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darkz

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Re: VCE Biology Question Thread
« Reply #11868 on: August 18, 2019, 12:09:52 pm »
+2
Are a selecting agent and a selection pressure the same thing or are they different?

Yes, they can be used interchangeably.
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Evolio

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Re: VCE Biology Question Thread
« Reply #11869 on: August 24, 2019, 01:26:52 pm »
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Yep, you'd assume that there are no differences at the time of divergence. Maybe in the ideal world, there would be the same number of mutations having occurred, but since you can have things like A -> T -> A, which you wouldn't be able to detect, it is all very theoretical.
Thanks, darkz!

Hi guys!
I have a few questions I want to clarify.

1. Does allopatric speciation occur at the same time? Like, there was a question on checkpoints asking whether allopatric speciation occurred based on analysing a phylogenetic tree. I said no because the different bat species speciated at different times and not the same time, thus it wouldn't be allopatric speciation.

2. When asked to define gene pool, I said the total collection of genes present in a population. Checkpoints said that it is wrong to say this. Is it because it sounds like I'm talking about the number of genes and it doesn't focus on the variations of the gene(allele)?

3. Also, mitochondria DNA, is single stranded and circular right? Because it was thought to once be a prokaryote?
Thanks in advance!
 ;D

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #11870 on: August 24, 2019, 02:08:03 pm »
+2
Thanks, darkz!

Hi guys!
I have a few questions I want to clarify.

1. Does allopatric speciation occur at the same time? Like, there was a question on checkpoints asking whether allopatric speciation occurred based on analysing a phylogenetic tree. I said no because the different bat species speciated at different times and not the same time, thus it wouldn't be allopatric speciation.

2. When asked to define gene pool, I said the total collection of genes present in a population. Checkpoints said that it is wrong to say this. Is it because it sounds like I'm talking about the number of genes and it doesn't focus on the variations of the gene(allele)?

3. Also, mitochondria DNA, is single stranded and circular right? Because it was thought to once be a prokaryote?
Thanks in advance!
 ;D
1. Depends how many groups you're talking about. If you've only got two groups (which is the most common scenario) then they must speciate at the same time because when group A can no longer interbreed with group B, then group B also can't interbreed with group A, therefore they're different species.

If you're talking about more than two groups then they can speciate at different times - for example if three groups of the same species are separated onto three different islands, they each become their own species when they can no longer interbreed. So if group A can no longer interbreed with either group B or group C then it's a separate species, but if group B and group C can still interbreed then they're still the same species, and it might take longer for them to speciate. Generally the evidence you need to know that it's allopatric speciation is just to know that the speciation occurred due to geographical separation.

2. Say the total variety of genes instead (also don't worry about having perfect definitions for the exam, you won't need them).

3.It's double stranded & circular
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Comet striker

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Re: VCE Biology Question Thread
« Reply #11871 on: August 25, 2019, 12:27:19 pm »
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Hey there,
During bacterial transformation, why are non recombinant plasmids added along with recombinant plasmids? Why not only add recombinant plasmids?
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Erutepa

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Re: VCE Biology Question Thread
« Reply #11872 on: August 25, 2019, 01:13:38 pm »
+3
Hey there,
During bacterial transformation, why are non recombinant plasmids added along with recombinant plasmids? Why not only add recombinant plasmids?
they aren't intentionally added as such, but rather they are added since the recombination process isn't perfect. Some plasmids don't successfully take up the desired gene in the recombination process and thus remain boring old plasmids. Thus, after bacterial transformation, some bacteria will possess just boring old plasmids and in order to obtain only bacteria with the recombinant plasmids, some sort of selection process will be preformed.
I suspect the reason for this is that it is easier to select for the bacteria with the recombinant plasmid rather than selecting for the recombinant plasmid itself and then performing bacterial transformation with the desired plasmids only.
Hopefully that makes sense. :)
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Chocolatemilkshake

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Re: VCE Biology Question Thread
« Reply #11873 on: August 28, 2019, 07:33:15 pm »
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Hi all,

Is it necessary to know the different types of phylogenic trees and what a cladogram is? Or do you just need to be able to formulate a general phylogenic tree/interpret them?

Thanks  :)
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Erutepa

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Re: VCE Biology Question Thread
« Reply #11874 on: August 28, 2019, 08:34:15 pm »
+2
Hi all,

Is it necessary to know the different types of phylogenic trees and what a cladogram is? Or do you just need to be able to formulate a general phylogenic tree/interpret them?

Thanks  :)
is this for units 1/2 or units 3/4 biology?

for units 3/4 you do not need to know about phylogenetic trees or cladograms. That was taken out of the study design as of 2017.

For units 1/2 you do need to know about phylogenetic trees, but I'm not sure about the specifics you are asking (I don't remember much 1/2 bio)

EDIT: please disregard my incorrect statement above.
 I unfortunately confused phylogenetic trees with pedigree charts and just realised now how foolish i have been. Pedigree charts are not needed, but you do need to know how to interpret phylogenetic trees in relation to the relatedness of different species just as Phoenixx Fire has said below.
« Last Edit: August 29, 2019, 10:44:31 am by Erutepa »
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Chocolatemilkshake

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Re: VCE Biology Question Thread
« Reply #11875 on: August 28, 2019, 09:26:09 pm »
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is this for units 1/2 or units 3/4 biology?

for units 3/4 you do not need to know about phylogenetic trees or cladograms. That was taken out of the study design as of 2017.

For units 1/2 you do need to know about phylogenetic trees, but I'm not sure about the specifics you are asking (I don't remember much 1/2 bio)

Units 3/4. Okay thanks that is super helpful!
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PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #11876 on: August 28, 2019, 09:40:20 pm »
+2
^You do still need to know about phylogenetic trees. You just need to be able to use them to determine relatedness though (so you need to be able to look at one and tell which species are more closely related/diverged more recently)
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caffinatedloz

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Re: VCE Biology Question Thread
« Reply #11877 on: August 29, 2019, 10:25:54 am »
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Adding on from this...



Are species A and B equally related to species C or would species B be closer related because of the order they are written?

PhoenixxFire

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Re: VCE Biology Question Thread
« Reply #11878 on: August 29, 2019, 10:51:10 am »
+1
A and B are equally related to C. You could switch A and B and it would still be the same cladogram.
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caffinatedloz

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Re: VCE Biology Question Thread
« Reply #11879 on: August 29, 2019, 12:32:14 pm »
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Awesome! Thank you PF!