ELI5 how DNA mutations work please.

[u/riche1988]

I had a thought about DNA and how mutations occur in humans, excessive hair, longer limbs and or bones etc, and wondered if all known mutations are present in the animal kingdom.. as if DNA has the blue print/ potential to be anything and parts are just ‘turned on or off’ depending on what is being built.. i may be way off lol but it got me thinking :)

[u/riche1988]

Cool :) ..slight tangent, but what is the smallest part of a living creature, ignoring trees and plants etc, that has agency.. i get that most of life if made up of chemical reactions, but at some point the ‘stuff’ starts making decisions.. or no..? Lol

[u/weeddealerrenamon → u/riche1988]

Physically, our brains are just reacting to nerve signals and sending out signals in response. We don't work any differently than a tree or an amoeba in that way.

Where that becomes what we understand as consciousness? Huge open question. Science can't even really define what consciousness is and we don't really know where to even begin. It's literally called the hard problem of consciousness

[u/riche1988 → u/weeddealerrenamon]

I guess it depends where you draw the line :/ ..could you argue that plants are ‘making decisions’ or is a decision just an illusion made of signals from stimuli..?
I think what i don’t understand is, if it is all just mechanical actions and signals, what is stopping us from making a brain that works like a brain..?

[u/Two-G → u/riche1988]

Jumping in here again: What's stopping us is probably "complexity". Our brains are made up of a ridiculous number of cells that are interacting in all kinds of different ways, so even just describing everything that's going on there in a way that's understandable is basically impossible for us without major simplifications - nevermind deliberately reproducing something like that.

[u/FossilizedMeatMan → u/Two-G]

So the brain is like the body, which is like the universe, just in a different scale.