Question about origins of survival and instinct

[Nexus555]

Hello, I have a question concerning life, evolution and most importantly - instincts.

I understand the theory of evolution, however the one aspect that I do not understand is why do these collections of atoms that form molecules, etc, form a will to survive? I understand the biological side of life, however when it comes to instincts and such, how do we form those in the evolutioniary process? Why is it that life at the even most basic form, want to eat, survive, reproduce and form instincts? How does it know to perform these functions. While I know these are features only unique to life itself; how can lifeforms form these instincts?

 

[Sojourner01]

Why is this any different to any other trait? A life form that can't be bothered to survive...well, won't. The very early microbes most probably existed in a state where they had no option but to exist - they wouldn't have had to do anything except allow chemicals to diffuse into them.

 

[Nexus555]

Why is this any different to any other trait? A life form that can't be bothered to survive...well, won't. The very early microbes most probably existed in a state where they had no option but to exist - they wouldn't have had to do anything except allow chemicals to diffuse into them.
--------------------------------------------------------------------------
I don't think you answered my question. I can understand what you meant when you said "The very early microbes most probably existed in a state where they had no option but to exist - they wouldn't have had to do anything except allow chemicals to diffuse into them." however this does not answer my question. Let me restate: How do the early stages of lifeforms (single celled organisms, etc) learn their instincts?

Now I can see how when they acquire these traits they can survive more and more efficiently over time, evolve to their surroundings for best survival abilities etc, but how does the very first instinct develope?

 

[Nexus555]

Can anyone answer this question?

 

[Moridin]

It is not organisms that learn these behaviors such as eating, reproduce etc. and then pass it on to their offspring. It is just that those who do not possesses them from the start dies. This demands an initial genetic diversity. Inheritance of acquired characteristics does not happen (provided that these characteristics is not related to the sex cells).

 

[Nexus555]

It is not organisms that learn these behaviors such as eating, reproduce etc. and then pass it on to their offspring. It is just that those who do not possesses them from the start dies. This demands an initial genetic diversity. Inheritance of acquired characteristics does not happen (provided that these characteristics is not related to the sex cells).

Again, this does not answer my fundamental question. I can clearly see how those who do not acquire them from the start will die, because they have no motive to want to survive. Again: How did the very first single celled oraganisms ACQUIRE these traits of instincts? I see how they are passed on and such, and how evolution works, but how do they obtain these basic instincts? The biological factor seems very easy to understand, and how they slowly adapt to their evironment and such... but what about this.

 

[DaveC426913]

Programs are not instincts

How did the very first single celled oraganisms ACQUIRE these traits of instincts?

Behaviour in very simple organisms is programmed. It is not a "survival instinct"; it is simply a cause and effect chemical process built completely by trial and error over generations. The program is passed from one generation to another. The program is altered by various mutative processes. It does not matter what processes, only that the program can be mutated.

Moths do not fly toward lights because of instinct; they fly towards light because their wings are light sensitive panels. If more light falls on one wing than the nother, a signal is sent to the opposite wing to cause it to beat harder, turning the moth toward the light (an oversimplification).

The point is, there is no brain activity involved. It has no "choice" in the matter (though it might have competing programs, such as being swatted at). It has no instinct. However, this program has served it well over millions of years, even if it is not very adaptable. The moths program can't distinguish between the sun's life-giving light, and Early Man's nighttime campfires.

But as organisms become very complex and acquire more sophisticated nervous systems, they can have chemical processes that happen internally, making one process affect the input and outcome of another process, all resulting in small changes that occur before any action occurs externally. This can lead to very complex behaviours resulting from very subtle changes in inputs (such as a bird spotting cat and deciding to fly away from it). These can be called survival instincts.

 

[DaveC426913]

Read my https://www.physicsforums.com/showpost.php?p=1231581&postcount=13" again.

The moth does not instinctively fly towards light. It is a program that has served it well. And it is a program that evolved. But it is not a survival "instinct"; it is purely a chemical process.

 

[DaveC426913]

Nexus: long before there were survival instincts, there were simple stimulus response mechanisms that kept critters out of trouble. It was only when nervous systems evolved, that instincts (which are really nothing more than very sophisticated and subtle stimulus:response mechanisms) became possible.

A paramecium's reaction to being touched by a predatory amoeba is purely chemical/mechanical, and cannot - except by the most optimistic mind - be called an instinct.These are still what rule us today, even as sophisticated as humans, though we like to think that our intelligent behaviours are the primary drivers. Burning yourself on a stove and yanking your hand away actually has nothing to do with instinct; it doesn't even have to do with the brain. The stimulus (pain sensors) is processed at the spinal cord, resulting in a direct signal to the muscles (response). It is not instinctive.

 

[Vorticella]

Again, this does not answer my fundamental question. I can clearly see how those who do not acquire them from the start will die, because they have no motive to want to survive. Again: How did the very first single celled oraganisms ACQUIRE these traits of instincts? I see how they are passed on and such, and how evolution works, but how do they obtain these basic instincts? The biological factor seems very easy to understand, and how they slowly adapt to their evironment and such... but what about this.

Nexus, you must understand the process of a single cell into a multicellular organism took billions of years. Some organisms had receptors and some did not. The organisms with a new receptor might possesses some sort of environmental niche. For example, many animals, especially mammals, can taste bitterness. Why is this? There are receptors on the very back of the tounge that bind with Nitrogen containing compounds. Many of these compouds are toxic and ellicit a response to the brain that tells us "hey, this doesn't tase so well." Therefore this one a instinct that evolved over many many many years. Another example is the parasympathetic and sympathetic impulse to the iris of the eyes. When the sympathetic nervous system takes over, heart rate and respiratory rate elevate. This in turn ellicits a response to the iris contracting it causing the pupil to dialate, causeing more light to enter and a larger viewing area is created. This happens when an animal is excited or in danger, aka the "Fight-or-flight response. This is enother example of a trait that evolved over many years giving that particular organism a certain niche. If this doesn't answer your question, please ask the question with a little more detail. The evolution from a single cell to a multicellular organism such as a human is extremely complex and took hundreds and hundreds of millions of years.