How is physics relevant to understanding living organisms?

[Scott Sieger]

I posted this here because seemed appropriate for theory development. As I am interested in physics thinking on this subject.

How does physics apply to living organisms?

Are any of the physical laws relevant?
Do conservation laws apply?

How can physics relate to say a dog or a cat?

How does GR or Sr apply to annimate objects? Or does it?
The reason I ask these questions is that when we think physics we tend to only think about "the solid stuff" or "the hard stuff" but how do we apply physics to a living organism?

Until life is included in the physics picture can we say we are close to the truth?

 

[WWW]

Hi Scott Sieger,

First I think we have two basic possibilities to know something:

1) The built-in knowledge that is based on our internal systems (DNA, central nervous system, and so on).

2) The external knowledge that is based on the external world, and become our paradigm point of view trough a continuous educational process, which is a very complex combination of relations between our internal built-in properties and what we recognize (by using senses and cognition) as the external environment.

3) There are also internal and external sources of knowledge which are beyond our abilities to fully know them but they have a deep influence on our life (for example: sub-consciousness and another internal fine processes within us, or variety of external physical fields of energy or kinds of matter that we still not aware of).

Now for your question, the most advanced research (as much as I know) which is deeply connected to your question, is the research of complexity or what is called complex systems.

Scientists from different branches of science finding that if they want to ask and get meaningful results on complex systems, they have no choice but to find new ways to communicate between, so called, different scientific areas.

If we take a “bird’s eye” on this process, we find that complex systems have some kind of an “internal organization force” that influencing on any system (and in this case the scientific system itself) that interacting with it.

More to the point, we as living complex organism trying to understand the laws (if exists) that governing complex systems, and by understanding them, we hope to understand better our internal and external relations in, what we call, our universe.

Is complexity can be reduced to some simple physical laws, or not? Is one of the most interesting and important questions that we can ask, and in my opinion, I think we have a very long way full of surprises in front of us.

 

[LURCH]

...How does physics apply to living organisms?

Are any of the physical laws relevant?
Do conservation laws apply?

How can physics relate to say a dog or a cat?

Physocal life is entirely dependant upon physical laws.

Let's start with Newton; An object at rest tends to remain at rest, an object in motion tends to remain in motion. For every action there is an equal and opposite reaction.

This is why you don't run full-speed at trees. It's why you duck when heavy objects fly at you. It's also why you have to go get things instead of waiting for them to get up and come to you.

And then there's entropy. You eat, the food goes into your digestive tract and breaks down, releasing energy. This energy your body uses to repair danmaged parts, build itself up, and power all your movements. If you don't eat, your body continues to expend energy and break down. So if it weren't for the law of entropy constantly eating away at you r body, you wouldn't need to make use of the law of entropy (by eating) to supply your body.

A little fluid dynamics? Well, since you ask...
So your heart pumps, creating pressure. Pressure causes fluid to move from where the pressure is greater toward an area of lower pressure, and your blood moves through your veins.

Then there's the laws of electromagnetic charge that govern your nervous system.

In fact, there's nothing that takes place within your physiacl body that isn't an application of physical laws.

 

[Mike H]

There is an entire area of research which is dedicated to applying our knowledge of physics to biology, and is named "biophysics." It is rather broadly defined, so there can be quite a bit of material to wade through.

If you are serious about understanding this topic, I would recommend you take a look at the http://www.biophysics.org/btol/ which covers quite a bit. It is, I should note, a work in progress so it is not by any means finished or even comprehensive for that matter. But it does serve as a nice starting point, in my opinion.