What happens after long periods of natural selection?

Answer 1

Natural selection is the phrase used to describe the phenomenon of differential reproductive success, meaning that some variants will, on average, produce more offspring than other variants, allowing the alleles that give them this reproductive fitness to spread throughout the population at a faster rate than their rival alleles.

Basically, natural selection is what gives evolution "direction." Without natural selection, evolution could be imagined as an expanding circle, with new genotypes forming in every direction. With natural selection, evolution becomes a line that moves off into a particular direction, determined by environmental factors.

So imagine putting a pencil on a piece of paper and drawing a short stretch of line. That's what a short period of natural selection does. Now to understand what longer periods achieve, just extend the line.

Of course in reality, conditions are always changing, so the line won't be a straight line. Also, sometimes speciations occur, and the line will split into two or more lines, like a branching tree.

But basically what happens is that life changes and will continue to change, further and further away from the starting point of the line.

Answer 2

After long periods of natural selection, populations may undergo changes in their genetic composition as certain traits become more prevalent due to their adaptive advantages. Evolutionary processes such as speciation and adaptation can occur, leading to the emergence of new species with different characteristics shaped by their environment.