Inductive reasoning about evolution?

Question

Since mutations ocuur when a bacteria divides, it is safe to assume that in multicellular species when two cells undergo meiosis, mutations happen too. (If this statement is wrong, please point it out). And since most cells are completely functional without the rest of the body (provided their strata resembles the blood from its species), we can argue they have the ability to adapt to their sorroundings as independent species do (again, Im only assuming, so I may be wrong) by mutation and natural selection. Now, if these statements are true, body cells may evolve and make themselves fitter and therefore, making the individual healthier and less prone to dying from epidemics or poisoning.

Now, a second thought: isnt this process exactly what makes the ability to become somewhat more inmune to some poisons by injecting a growing dose of them gradually?

Answer 1

your statements are not quite accurate. mutations do occur in our cells all the time, but our DNA repair systems are very robust. even if a mutation get through (which they do once in awhile) it won't likely be in a gene or regulatory element that it important to that cell, meaning there won't be any effect on the cell. if a mutation does affect a cell or group of cells, and there is a selective advantage to that new cell, then yes it may make the individual healthier. however, those mutations would not likely affect the germline and therefore won't be passed down through generations.

in the case of poisoning, usually the body enhances its natural protection, but not through mutations.

Answer 2

>"when two cells undergo meiosis, mutations happen too."

Yes. But meiosis only occurs in the production of gametes (sex cells ... sperm or egg cells). But since the rest of your question is about normal body cells, not sex cells, I'm guessing you mean mitosis, not meiosis.

>"body cells may evolve and make themselves fitter and therefore, making the individual healthier and less prone to dying from epidemics or poisoning"

It's an interesting theory. The problem is that natural selection involves replication with inheritance. As you say, mitosis is exactly that ... replication of body cells with inheritance. However, that replication is mostly local (a skin cell that develops a mutation, will replicate only in its own vicinity) ... if that skin cell were to spread and replicate throughout the body, this is similar to metastasis of a cancer.

However, your theory is not without merit. In a way, this is the way that the body develops antibodies to pathogens (and resistance to toxins). However, it's not so much that the cells themselves evolve resistance, but rather, after many white blood cells die trying to fight off the bacterium or virus, they eventually produce some protein (the antibody) that neutralizes the pathogen. Once this occurs, then the cells that produce this protein (the antibody) themselves replicate using mitosis, to produce more of it. This fends off the current attack, and prepares the body to produce more of that antibody if it is attacked again by the same bacterium or antibody.

An interesting theory.

Answer 3

Don't confuse adaptation with mutation. Cells often have mechanisms by which utilization of a pathway creates an up-regulation of the enzymes in the pathway. This is the mechanism of tolerance.

There are ways that mutations alter survival patterns of single cells. This is cancer. Altered DNA enhances the ability to grow independent of normal organismal regulation, evade the immune system, and tolerate chemotherapy.

Answer 4

Have you figured in the difference between somatic cells, which die with the organism and germ cells that provide the heritability of traits?