Re: Is there a forseeable end to evolution? Can evolution go on forever?

To: Jim Henriques
Dear Jim,

Q:  Can evolution go on forever?

A:  Yes.  Evolution can and does go on as long as there are living things.  
In each generation there are changes in gene frequency in a population due 
to mutation, drift, and selection.  Evolution is going on right now but in 
organisms like humans it is too slow to be noticeable.  Changes are 
noticeable over 10,000's of years.  However, you can, each year, find 
examples of evolution in bacteria - just read the medical reports of 
strains of bacteria which are resistant to antibiotics like vancomycin or 
ampicillin.  (Or mosquitoes that have become resistant to DDT.)

Q:  Is there a foreseeable end to evolution? 

A:  No.  One of the common mistakes in thinking about evolution is the idea 
that evolution is a goal oriented process, but it is not.  Evolution is 
blind.  All that is happening is that certain organisms or individuals 
survive and propagate through time - changes are due to which individuals 
survive - there is no final product.  As a hypothetical example, take a 
bacterial strain that grows better on glucose than galactose.  Grow it one 
galactose and you will select for mutants that grow better on galactose.  
Then grow it one glucose again and you will select for mutants that grow 
better on glucose.  Evolution has occurred but the net result is that you 
are right back where you started.  You can also see evidence that evolution 
is blind in terms of animal specialization.  In most cases, species that 
are ecological 'generalists' survive longer than specialists - yet time and 
time again species become specialists as niches become available - they 
cannot "see around the corner" that their "ecological niche choice" is a 
historical dead-end.

If you have questions e-mail me at mccarter@genetics.wustl.edu

Sincerely,

Jim McCarter
M.D. / Ph.D. Student 
(interests: development, genetics, parasitology, evolution, genomics, drug 
design)