Changes

== Variation and Randomness ==

== Variation and Randomness ==

Natural selection becomes interesting when there is the possibility of random variation in the duplication of individuals--in other words, when an individual is copied, the copy may be slightly different from the original.  It is important to note that, as stated above, the ''mechanism'' for this variation is not explained or even taken into account by natural selection.  All that matters is that there is ''some'' process that produces variation. In this case, some of the offspring of an individual will be better (where "better" is defined as "more likely to successfully reproduce"--one can think of it as scoring higher on an evaluation) and some will be worse.  The higher-scoring offspring will soon come to dominate the population, and over successive generations the average score will also rise.

Natural selection becomes interesting when there is the possibility of random variation in the duplication of individuals--in other words, when an individual is copied, the copy may be slightly different from the original.  The random sources for this variation include mutations and recombination, or "crossing over", during meiosis.  All that matters is that there is ''some'' process that produces variation. In this case, some of the offspring of an individual will be better (where "better" is defined as "more likely to successfully reproduce"--one can think of it as scoring higher on an evaluation) and some will be worse.  The higher-scoring offspring will soon come to dominate the population, and over successive generations the average score will also rise.

==Role in Life Sciences==

==Role in Life Sciences==