Force/agent of changes

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biology_06er
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Force/agent of changes

Post by biology_06er » Sun May 14, 2006 11:07 am

Hi there

I was just going through a past exam paper (felt pretty confident I knew my stuff)!!!...Then I come across a question and well....here I am...

What does it mean force or agent of change eg: An African butterfly species exists in 2 strikingly different colour patterns...and its a table (of fill ins)..and it asks for the force or agent of change????

are the options such things like natural selection, cladogenesis, I don't know!!!

Any help would be much appreciated
biology_06er

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mith
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Post by mith » Sun May 14, 2006 5:31 pm

evolutionary pressures, such as whether the environment is more suitable to one coloration as opposed to another.
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AstusAleator
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Post by AstusAleator » Mon May 15, 2006 1:45 am

with butterflies, it's probably either predation or sexual selection.

http://www.millerandlevine.com/km/evol/Moths/moths.html
What did the parasitic Candiru fish say when it finally found a host? - - "Urethra!!"

biology_06er
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Post by biology_06er » Tue May 16, 2006 4:29 am

Hi there

Thanks for that...but I still don't really get it...I get that the butterfly would adapt to the environment...but other "forces"....is there a list or something?....another example say is...pathogenic bacteria found in many bacteria found in many hospitals are antibiotic resistant..what force/agent of change is this?


whaaaaaaaaat?

Thanks
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mith
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Post by mith » Tue May 16, 2006 4:54 am

the antibiotic, it causes only the resistant ones to live..
Living one day at a time;
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Accepting hardships as the pathway to peace;
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Doc44
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Post by Doc44 » Tue May 16, 2006 4:56 am

Hospitals are supposed to be very clean places; lots of cleaning chemicals and disinfectants used alot. The people infected with pathogens including bacteria are given a wide variety of antibiotics. All of this is to kill bacteria. This stuff kills most of the bacteria but if some of the bacteria happen to mutate (genetic change) in a way where they are not affected by the antibiotics and cleaning stuff then they are there to continue to reproduce more bacteria like themselves, resistant. The non-resistant bacteria get killed off leaving mainly the ones that the stuff doesn't kill. The antibiotics and cleaning chemicals act as the selective force to "select" the most fit bacteria which can survive in that environment, the hospital. Thats why hospitals are producing these new super bacteria and so many people with a simple infection or broken leg go to the hospital and get a really sick from a supper bacteria then got while in the hospital. We make new antibiotics which make tougher bacteria. This is evolution in progress....survival of the fittest. Of course you also have to remember that bacteria reproduce very quickly and there are a bunch of them. This increases the chances of a positive mutation happening.

Doc44

And of course the drug companies love it all the way to the bank.

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