Before we start, allow me to remind you that evolution is possible when two characteristics are present in a population: inheritance and variation. Find out what they are.
Now let’s see how it works.
Six people at the table. One of the guys picks a sheet, writes nine digits and passes it around the table.
Scenario uno. The sheet is passed from guy to guy, and every one of them just passes it on. Several laps later:
Voila an example of inheritance without variation. The sheet has constant traits that are passed on unchanged. It does not evolve.
Scenario due. Every guy receiving the sheet dumps it without looking, and writes a new one, then passes on. One lap later:
Variation without inheritance in action. Every person writes new info on a sheet but ignores the old one. As he/she never got it in the first place. Nine digits change spasmodically. They might be similar to one of the past states (sheet 2 and sheet 4, for example), but due to chance only: person 4 never new what was on sheet 2.
Scenario tre. Every guy erases one digit and replaces it with another, randomly. And passes the sheet on. Next guy does the same thing.Three laps later:
Finally, evolution in action. Every guy makes a change based on just received info. Moreover, every new change is saved and passed on, and every guy edits the last version of the blueprint. We can observe the occurrences intrinsic to evolution:
- Gradual change. Neighbouring edits are similar, but the first and the last ones have almost nothing in common.
- Regressive evolution. Edit 5 is the same as edit 3. It happened due to chance.
Scenario quattro. Guys change one digit like in previous scenario. But now they were instructed to always change the smallest digit, with anything they want. Three laps later:
This is an example of selection. We sift small numbers away, cause that’s the criteria of selection. You can see how digits become larger and larger with every lap. Smalls pop up occasionally, but disappear immediately. Selection suppresses small digits. At the time, large digits are the most secure, as you can see.
In the same exact manner wolves select slowest deers, so that only fastest remain. And people sift away the least productive cows in favour of the most productive.
Q: How could wolves select the slowest deer? One has to be sentient to select.
Wolf is sentient enough to notice a slow deer, based on scent, manner of walking and so on. Even if it’s not sentient – it simply won’t catch a fast deer. Selection is simple as that.
Disclaimer: for simplicity, such topics as mutation, gradual change vs punctuated equilibrium and some others have been avoided.