If you have paid attention to the headlines during the last twenty years, you are probably aware of stem cells. A popular understanding of stem cells, at least, what I have understood, is that these early embryonic cells hold the potential to transform into every different type of cell an organism will possess.
However, as these cells divide and the embryo grows, stem cells begin to become specified as a particular type of cell. As this transformation occurs they lose the ability to become alternative cell types. Eventually, they fill a particular niche wonderfully, but have lost the ability to become a radically different type of cell.
Stem cells can serve as a metaphor illustrating a powerful idea regarding Darwin’s proposed mechanisms for evolution. Research reveals that random mutations and natural selection do transform species, however, at a surprising cost. Continue reading “Evolution’s random mutations and natural selection”