HSC Biology Question Thread

[Natasha.97]

Hey,

What is the difference between Divergetn and convergent evolution?

Hi

Just adding onto the above answer with examples:

• Convergent Evolution: Dolphins (Mammals) and Sharks (Fish)

           - Analogous structure: Streamlined shape and fins
           - Purpose: Propulsion and stability for movement in a viscous environment

• Divergent Evolution: Pentadactyl limb (Mammals)

           - Homologous structure: Five digit limb
           - The limb is found on humans/cats/bats/whales, but perform different functions depending on their environment

Hope this helps 

[vox nihili]

Hi

Just adding onto the above answer with examples:

• Convergent Evolution: Dolphins (Mammals) and Sharks (Fish)

           - Analogous structure: Streamlined shape and fins
           - Purpose: Propulsion and stability for movement in a viscous environment

• Divergent Evolution: Pentadactyl limb (Mammals)

           - Homologous structure: Five digit limb
           - The limb is found on humans/cats/bats/whales, but perform different functions depending on their environment

Hope this helps 

Are you sure that sharks and dolphins' body types are an example of convergent evolution? The earliest mammals developed in the ocean as I understand it, therefore they probably started off with a structure that they inherited from fish. They subsequently diverged.

Analogous structures imply that they both independently evolved the same thing, but I'm not sure that's the case?

[Natasha.97]

Are you sure that sharks and dolphins' body types are an example of convergent evolution? The earliest mammals developed in the ocean as I understand it, therefore they probably started off with a structure that they inherited from fish. They subsequently diverged.

Analogous structures imply that they both independently evolved the same thing, but I'm not sure that's the case?

Hi

From what I have been taught in class and a browse through Google to make sure, dolphins evolved from land-based animals

[vox nihili]

Hi

From what I have been taught in class and a browse through Google to make sure, dolphins evolved from land-based animals

Well there you go. That's really odd!

[Mymy409]

Hi! In Communication, will we ever have to draw the structure of an entire eye?

[Natasha.97]

Hi! In Communication, will we ever have to draw the structure of an entire eye?

Hi!

I've seen past questions on this before (attached image from 2009 HSC)



It helps in memorising the relationship between the different structures of the eye and their functions.

Hope this helps!

EDIT: Contradicted myself when I said "It may not be asked", when I attached an example of a previous question...

[Mymy409]

Hi!

I've seen past questions on this before (attached image from 2009 HSC)

(Image removed from quote.)

Even if it may not be asked, it helps in memorising the relationship between the different structures of the eye and their functions.

Hope this helps!

Oh, yikes, it was actually asked, lol. Thanks!

[Daniyahasan]

Hi! In Communication, will we ever have to draw the structure of an entire eye?

Yep they can ask you that, and its a pretty simple diagram so dont stress too much:)

[Daniyahasan]

Hey guys
Can someone pls explain how I would structure my answer for this question
Thanks

[Opengangs]

Hey guys
Can someone pls explain how I would structure my answer for this question
Thanks

It's a six marker, so it requires you to have an extensive knowledge behind the reproductive techniques and genetic diversity. So, to help us break down the six marks, we need to locate appropriate and relevant information and then break these information down into its components.

So, breaking down the marks can look something like this:

1 mark -- briefly outlines what modern reproductive techniques are and how they can limit genetic diversity.
2 marks -- identifies and discusses the use of modern reproductive techniques in animals. (I would probably choose 4, but mingled with plants)
2 marks -- identifies and discusses the use of modern reproductive techniques in plants. (I would probably choose 4, but mingled with animals)
1 mark -- sustains a logical response / terminology.

Some more pointers:
Here are the list of possible reproductive techniques you can talk about.

Techniques
Artificial insemination
Artificial pollination
Cloning
Transgenic species

Examples
Bt cotton
GloWorm fish
Transgenic salmon
Dolly (through Somatic Cell Nuclear Transfer)

If you need, I can provide you a sample answer that I may have written and I'll walk you through why I did it.

[itssona]

1.   Which of the following was present in abundance when organic molecules first developed on earth?

a)   Bacteria
b)   Oxygen
c)   Glucose
d)   Water

thank youuu

[Aaron12038488]

its either A or D, i think maybe d as water vapor was an integral part in the early earths atmosphere idk. but im going with D.

[Natasha.97]

1.   Which of the following was present in abundance when organic molecules first developed on earth?

a)   Bacteria
b)   Oxygen
c)   Glucose
d)   Water

thank youuu

Hi!

Not A: Bacteria were formed after organic molecules first developed (first appeared 2.5bya e.g. cyanobacteria)
Not B: There was a lack of O₂ in the early earth, only volcanic gases were present
Not C: No organisms were present to produce glucose as a source of energy
Therefore, the answer is D.

Hope this helps

[laura.akkari]

Hi I've really struggled with graphs like no matter how hard I try I always seem to stuff them up (maths has never been my strong point). I just wanted to clarify a few things bc I've gotten different responses from different teachers about certain things. Firstly I don't understand when you are supposed to join the dots or draw a line of best fit (I lost a mark in trials for drawing a LOBF). Also I get confused over whether you are supposed to connect the first dot to 0 or not ? Thirdly, I find I always have doubt over whether to use a bar or line graph and I always end up picking the wrong one, I understand that line is usually continuous data and discrete for bar (I think), but I still get confused about it all like in one of my exams they wanted a bar graph for an experiment involving time?? Anyway, some clarification would be super helpful as the graph in trials seriously stuffed up the majority of my exam after I did the entire thing wrong after spending 15 mins on it and had to start all over again (leaving me with 5 mins to do the 7 marker which was not ideal haha). 

[itssona]

Hi!

Not A: Bacteria were formed after organic molecules first developed (first appeared 2.5bya e.g. cyanobacteria)
Not B: There was a lack of O₂ in the early earth, only volcanic gases were present
Not C: No organisms were present to produce glucose as a source of energy
Therefore, the answer is D.

Hope this helps

thank you!!