Stromatolites (Multiple choice Q) (1 Viewer)

[Chrisssss]

I have a question on a work sheet which I haven't been able to come up with a definitive answer to, and was seeking opinions.

Stromatolites, an ancient cyanobacteria that have survivied in Shark Bay in Western Australia, are very similar to those found as fossil remains dating back millions of years.
Why have these ancient forms remained unchanged for so long?
a) The stromatolites are able to adapt to any environment
b) The environment has not changed significantly over time
c) The stromatolites have not been able to undergo mutations
d) The stromatolites are not able to adapt to a changing environment


Since Australia has changed significantly over time it can't be b), and since stromatolites still exist I doubt it's d), otherwise they wouldn't be around. Overall I'm thinking c), though I'm not really convinced.
Any responses would be appreciated.

 

[beentherdunthat]

EDIT; only {a} sounds logical because it means they undergo mutations/natural selection to adapt to the env.
- can't be {b} or {d}
and C will be ruled out coz it kind of contradicts darwins theory of natural selection

 

[Chrisssss]

EDIT; only {a} sounds logical because it means they undergo mutations/natural selection to adapt to the env.
- can't be {b} or {d}
and C will be ruled out coz it kind of contradicts darwins theory of natural selection

Good point regarding c), although I didn't think it was a) due to the fact that if 'they could adapt to any environment' it doesn't make sense why they would only currently exist in the unique conditions of Shark's Bay W.A. If they could adapt to any environment it would make sense that they would be dispersed almost worldwide.

 

[brenton1987]

if 'they could adapt to any environment' it doesn't make sense why they would only currently exist in the unique conditions of Shark's Bay W.A. If they could adapt to any environment it would make sense that they would be dispersed almost worldwide.

Stromatolites are just cyanobacteria and grains of sediment. Cyanobacteria is found all over the world.
I would definately pick a.

 

[midifile]

Since Australia has changed significantly over time it can't be b), and since stromatolites still exist I doubt it's d), otherwise they wouldn't be around. Overall I'm thinking c), though I'm not really convinced.
Any responses would be appreciated.

I think that it is b. Even though the environment over the whole of Australia has changed, there are certain niches that have remianed stable. If the stromalites environment changed dramatically, either there would have been changes in the population as certain varients are selected for or against, or the population would have died out. Therefore they wouldnt have survived unchanged for millions of years

a) - If the stromalites were able to adapt to new environments and the environment changed, then they would have changed, and therefore would not be the same as they were millions of years ago.
c/d) - If the stromalites were unable to undergo mutations and the environment changed (as you said Australia did), chances are they would have been unable to survive.

Hope that doesnt make it too confusing, seeing as I have contradited what you said.

 

[Shadose]

Stromatolites, an ancient cyanobacteria that have survivied in Shark Bay in Western Australia, are very similar to those found as fossil remains dating back millions of years.
Why have these ancient forms remained unchanged for so long?
a) The stromatolites are able to adapt to any environment
b) The environment has not changed significantly over time
c) The stromatolites have not been able to undergo mutations
d) The stromatolites are not able to adapt to a changing environment

At least its definitely not d
I doubt it would be a) as that means it would have survived everywhere world wide
Its either b) or c) for me ... I might have chosen b) as the most relevant answer.

 

[Chrisssss]

I think that it is b. Even though the environment over the whole of Australia has changed, there are certain niches that have remianed stable. If the stromalites environment changed dramatically, either there would have been changes in the population as certain varients are selected for or against, or the population would have died out. Therefore they wouldnt have survived unchanged for millions of years

a) - If the stromalites were able to adapt to new environments and the environment changed, then they would have changed, and therefore would not be the same as they were millions of years ago.
c/d) - If the stromalites were unable to undergo mutations and the environment changed (as you said Australia did), chances are they would have been unable to survive.

Hope that doesnt make it too confusing, seeing as I have contradited what you said.

Very good points. It still seems a bit unlikely to me although now taking into consideration your argument the rest seem even more unlikely.
Thanks.

 

[Campione]

Within any generation there will be a significant variation. Natural Selection introduces this, Stromatolites are just the same, since primeval Earth's climatic conditions, the versatility and resilience must be taken into account since for millions of years Stromatolites has existed and survived. Now that may have been found by Archaeologists and Palaentologists, this is what the conclusion has come to.

 

[aussiechick007]

lol, that was a question in my bio half yearly i did yesterday.... and i picked b so i hope its right!

 

[Undermyskin]

A is the most likely answer within this whole range of poor choices, I suppose.

D should be crossed out at first since the Aus environment has significantly changed over the last few million years. This also leads to the suspicion of B which we all know contradicts this fact.

C sounds weird to me because as far as I know from last year, there hasn't been any mention of any organism unable to undergo mutations especially under this mutagen-abundant period. Their DNA is made up of the same materials (nucleotides with base, sugar, phosphate, blah blah blah) so at least I can assure the affect of UV light on 2 pyrimidines next to each other is at least one likely cause for any organisms inhabiting in Aus.

A is pretty much well supported: climate of any place around the world must have changed significantly due to the constant movements of continents, plus the abundance of stromatolites around the world proves its ability to adapt to many types of environments. Generally, simple organisms can always survive and develop strongly when meeting favourable niches.

 

[aussiechick007]

now, i'd really love to know for sure what the answer is... will know when i get my bio exam back next week i suppose lol

 

[midifile]

now, i'd really love to know for sure what the answer is... will know when i get my bio exam back next week i suppose lol

Yes.. Please post it up when you know.

 

[Chrisssss]

I think that it is b. Even though the environment over the whole of Australia has changed, there are certain niches that have remianed stable. If the stromalites environment changed dramatically, either there would have been changes in the population as certain varients are selected for or against, or the population would have died out. Therefore they wouldnt have survived unchanged for millions of years

a) - If the stromalites were able to adapt to new environments and the environment changed, then they would have changed, and therefore would not be the same as they were millions of years ago.
c/d) - If the stromalites were unable to undergo mutations and the environment changed (as you said Australia did), chances are they would have been unable to survive.

Hope that doesnt make it too confusing, seeing as I have contradited what you said.

Oh yeh I forgot to give everyone the answer. The correct answer is as above, B. I spoke to my teacher about it and as midifile said although overall Australia has changed certain parts maintained. So thanks again for that post (I ended up choosing b).

 

[aussiechick007]

yes we got our bio papers back and i was right it was b