>>11418438>How does one mutation provide enough benefit to have any effect whatsoever on survival, let alone happen to also be passed down to offspring, which pass it down to their offspring (and so on)Honestly, evolution is not that hard to understand. Imagine a species of bird of which the males have a conspicuously long red tail. A tail that doesn’t make it fly any better. Let’s see if evolution theory can explain how a bird might end up with such a long red tail.
We assume that in the distant past the tails were not so long and not so red as we see them today. Let’s assume that the average tail used to be 2 inches long and brown, with a slight reddish hue. And today the average tail is 8 inches long with a bright red color.
So, we start with the old population and the first thing we notice is that both the tail length and the color vary between the individual males. The average might be 2 inches, but there are also males with shorter (1.5 inches) and longer (2.5 inches) tails. Same goes for the color. Some tails are brighter and redder end some are less colorful.
Even if we limit ourselves to one agent of evolution -in this case sexual selection- it is easy to see how long red tails can evolve.
As with many birds the females are doing the selection. They decide with which males they mate. As both the color and the length of the males’ tail indicate health and strength, the females prefer the longer and more reddish ones over the shorter en more brownish ones. The genes for both having a long red tail (in males) as well as preferring a long red tail (in females) will be passed on more frequently than the genes for having (and preferring) shorter tails. Hence, our species of bird will have males with longer and redder tails as the generations go by.
