Thanks Jeryl i appreciate that.
I'll elaborate a bit more on the protein. A protein has what is known as an 'active site' which basically means a place on the protein that gives the protein it's function. At this site are various aminoacid side chains which react with a very specific substrate (substance) and break it down. Proteins are made up of chains of aminoacids (AAs) which are folded in very specific ways, held together by weak forces and because of this they are extremely sensitive. Most proteins in humans if you heat them above 37C will begin to denature (unfold) and as a result the folding forming the active site changes so making the protein inactive. As you probably know, we call these proteins enzymes, and they form a vital role in the biochemiclal pathways in our cells. Hopefully that explains what i was talking about before.
Macro-evolution
Anyway, because enzymes rely on the 3D structure for their activity this means that disruption by mutation is very common since the 3D structure depends on the sequence of the AAs which depend on the genetic code which inturn can be altered by mutation. To cut a long story short it's very hard for a mutation to alter an existing enzyme without disrupting the enzymes activity in the process (which puts the organism at a disadvantage). The mutation has to alter the active site and in one go it has to change it so the active site now has a function it didn't have before (ie. Macroevolution). However since the previous enzyme played a role in an already existing pathway it must have a duplicate which isn't mutated inorder to still carry the existing pathway. The new enzyme must be useful and an advantage to the organism in order for its genetic sequence to be selected for and remain in the genome. The criteria for this is that there must be a substrate available that the new active site can act on (otherwise it's no use), there must be enzymes available to further react with the products of this first reaction or remove the fragments from the organism to prevent a build up toxifying it. The new enzyme must therefore fit in with existing biochemical pathways and not interfere with others by reacting with substrates that the other pathways need.
I'm only really brushing the complexity of the whole issue, that macroevolution is not a simple thing like microevolution. There are an awful lot of factors that have to be sastified at the same time inorder that macroevolution be possible.
I hope that helps explain what i meant when i was describing macroevolution previously.
Conferring an advantage to an organism is a general scientific term, not something i'm using to create an absurd case. Whether the mutation confers an advantage is not dependent on what an individual thinks - we can only tell that it has had an advantage by observing the 'fitness' of the organism once the mutation has occurred. If we observe the organism being worse off, being unable to compete as well in the environment and a lower reproduction rate as a result then the mutuation has had a negative impact on it. If we observe no change and things go on as before the mutation is described as neutral. If however we observe the organism competing in the environment better than before and reproduction rates increasing then the mutation can be said to have an advantage to that organism in that environment.
I'll elaborate a bit more on the protein. A protein has what is known as an 'active site' which basically means a place on the protein that gives the protein it's function. At this site are various aminoacid side chains which react with a very specific substrate (substance) and break it down. Proteins are made up of chains of aminoacids (AAs) which are folded in very specific ways, held together by weak forces and because of this they are extremely sensitive. Most proteins in humans if you heat them above 37C will begin to denature (unfold) and as a result the folding forming the active site changes so making the protein inactive. As you probably know, we call these proteins enzymes, and they form a vital role in the biochemiclal pathways in our cells. Hopefully that explains what i was talking about before.
Macro-evolution
Anyway, because enzymes rely on the 3D structure for their activity this means that disruption by mutation is very common since the 3D structure depends on the sequence of the AAs which depend on the genetic code which inturn can be altered by mutation. To cut a long story short it's very hard for a mutation to alter an existing enzyme without disrupting the enzymes activity in the process (which puts the organism at a disadvantage). The mutation has to alter the active site and in one go it has to change it so the active site now has a function it didn't have before (ie. Macroevolution). However since the previous enzyme played a role in an already existing pathway it must have a duplicate which isn't mutated inorder to still carry the existing pathway. The new enzyme must be useful and an advantage to the organism in order for its genetic sequence to be selected for and remain in the genome. The criteria for this is that there must be a substrate available that the new active site can act on (otherwise it's no use), there must be enzymes available to further react with the products of this first reaction or remove the fragments from the organism to prevent a build up toxifying it. The new enzyme must therefore fit in with existing biochemical pathways and not interfere with others by reacting with substrates that the other pathways need.
I'm only really brushing the complexity of the whole issue, that macroevolution is not a simple thing like microevolution. There are an awful lot of factors that have to be sastified at the same time inorder that macroevolution be possible.
I hope that helps explain what i meant when i was describing macroevolution previously.
