Will every population always converge to a “middle” that contains greatest amounts of whatever is being measured with “increasing” number of traits on wither side in order to make a bell curve visual distribution?

Question

Or are there populations where the curve graphs will converge on either end instead of the middle? Is it a fixed rule in Statistics that we “should” always have a bell curve distribution? If not, why does it seem like my data must make a bell curve distribution? Is it a rule in nature that that are greatest amounts of something in a group while slope downwards by number and value of trait towards the gretest middle and from it downwards? What is the special trait about the bell curve that it is underscored so much?

In: 2

Answer 1

Sorta

But it doesn’t start with the bell curve. That just describes what happens. There’s no magic bell curve constant that propagates through nature making sure distributions are following the rules.

It’s more that because of entropy and fierce competition among life forms, things tend to either regress to the mean or, if the trait is desirable, rise up to the new peak.

If a predator gets really good at hunting, the prey will get really good at evading. Not all prey. Some die out. But those don’t show up in the distribution do they?

It’s a case of winning traits being “adopted” by all and/or of outliers being killed off.

You see this in non living systems too, as the most stable state is low energy. And outlier high energy systems decompose until stable.

But there are other distributions. Lawyer salaries tend to be bimodal in the US for instance. Lotta people making $80k and lotta people making $200k+. Not as many outside of that.