Something seems like a mystery to me and since I'm not in biology field I don't know how to even guess the answer. Basically, if bacteria don't experience death as natural cause, then at any given time there should always bacteria that have "death-free" genes to pass to next generation. Sure, there might be mutation and evolution changes, but unless *all* bacteria mutate their genes to "death" genes, we'd expect there are bacteria that never die - naturally.
The question is why evolution has never come up with complex multi-cellular organism, out of bacteria, that don't have aging and death problem? Thanks for any comments.
in article [email hidden], namducnguyen at [email hidden] wrote on 4/26/04 9:47 PM:
Quoted message said:
Something seems like a mystery to me and since I'm not in biology field I don't know how to even guess the answer. Basically, if bacteria don't experience death as natural cause, then at any given time there should always bacteria that have "death-free" genes to pass to next generation. Sure, there might be mutation and evolution changes, but unless *all* bacteria mutate their genes to "death" genes, we'd expect there are bacteria that never die - naturally.
The question is why evolution has never come up with complex multi-cellular organism, out of bacteria, that don't have aging and death problem? Thanks for any comments.
Your thinking is based on the false premise that bacteria don't exhibit natural death. IMHO this is patently false, and I know of no evidence to the contrary.
The question is why evolution has never come up with complex multi-cellular organism, out of bacteria, that don't have aging and death problem? Thanks for any comments.
Have you heard of "negligible senescence"...?
``Caleb Finch at USC coined the term "negligible senescence" to describe very slow or negligible aging (Finch 1990). He listed several animals exhibiting it, including rockfish, sturgeon, turtles, bivalves and possibly lobsters. Later in a paper from the first Symposium on Organisms with Slow Aging (which the Director of this project also spoke at), Finch further described criteria to test the occurrence of negligible aging. These include no observable age-related increase in mortality rate or decrease in reproduction rate after maturity, and no observable age-related decline in physiological capacity or disease resistance (Finch and Austad 2001). [...]''
Of course this isn't common. It doesn't make much "economic" sense normally - and more than making everlasting cars or houses does. -- __________ |im |yler timtyler.orgtimtyler.orgOpen ↗ [email hidden] Remove lock to reply.
The question is why evolution has never come up with complex multi-cellular organism, out of bacteria, that don't have aging and death problem?
Onr reason is cancer. The problem any multi-cellular organism faces is to tell its cells, which are derived from billions of generations of divisions, that now is the time to stop dividing. One way of doing this is to incorporate a genetic counter, such as a stretch of DNA that isn't copied at the end of each chromosome, to limit the total number of divisions allowed. The consequence is that lifespan is also limited, but in evolutionary terms this is a small price to pay if the chance of surviving many years of predation, disease, famine and war is in any case negligible.
The question is why evolution has never come up with complex multi-cellular organism, out of bacteria, that don't have aging and death problem?
Onr reason is cancer. The problem any multi-cellular organism faces is to tell its cells, which are derived from billions of generations of divisions, that now is the time to stop dividing. One way of doing this is to incorporate a genetic counter, such as a stretch of DNA that isn't copied at the end of each chromosome, to limit the total number of divisions allowed. The consequence is that lifespan is also limited, but in evolutionary terms this is a small price to pay if the chance of surviving many years of predation, disease, famine and war is in any case negligible.
This is not a problem for most plants. Cancer mostly kills animals because the cancer cells can be distributed via circulatory systems.
Cancers in plants tend to be locked into a fibre matrix, are not mobile, and thus are rarely life-threatening.
Many (but not all) of the organisms that exhibit negligible senescence are plants. -- __________ |im |yler timtyler.orgtimtyler.orgOpen ↗ [email hidden] Remove lock to reply.
