In our discussions of plant adaptations and natural selection we talked about how a
random genetic mutation in a plant can result in characteristics that are
beneficial—or those that are harmful—to the plant. What exactly is a mutation,
and how does one occur?A mutation is a random
genetic variation that is passed on to offspring. For the most part, the replication of
chromosomes preceding cell division is flawless, and results in an identical copy.
However, occasionally random errors in the coding occur. These errors, or variations, are
called mutations.
What types of mutations are beneficial to an organism? One
example would be a mutation that gave a plant a bitter taste; this would discourage
herbivores from eating it. This plant would therefore have an advantage over its tasty
relatives, and would survive to reproduce, passing the bitterness to its offspring.
Other mutations cause harm to the organism. These
mutations might affect, for example, a plant’s resistance to disease, ability to
photosynthesize, or other factors affecting its ability to compete. Most harmful mutations
don’t persist for long in a species, because the affected individuals don’t
survive to reproduce.
And finally, many mutations are believed to have no effect
whatsoever on the organism.
Mutations—these random errors in the replication of
chromosomes—are one more factor ensuring genetic variability in a population.
