For our scientists, how did the complexities of our bodies originate.?

Question

I got this from another question. It made me think of our internal organs and all that they are designed to do. Does anyone have any theories how we got here from that common ancestor millions of years ago?

I think that God was the big bang and that is how we got these complex bodies we live in. I just want to know what the scientific community has to say about it.

http://answers.yahoo.com/question/index?qid=20070525122012AAezlGU&r=w

Answer 1

I apologize for the babbling nature of this post...

I'm not a biologist, but I'll try. The basic answer is that it happened through evolution, but you already know that.

I would start by saying that nothing is so complex that we can't understand its parts. Even the human mind, which is by far the most difficult to understand human organ, is made with very simple parts -- axons, dendrites, neurotransmitters, etc.

Think of it like this -- all the different material we have -- from iron to plutonium -- is made up merely of protons, neutrons, and electronics. And even those particles are probably made up of even simpler forms of energy. Historically thinking of everything as the sum of its parts is called, Reductionism:

http://en.wikipedia.org/wiki/Reductionism

Now, how did they come to be? When you get on a plane, you might think the shape of the plane is designed by humans -- it is not. A modern airplane is designed by a computer that simulates Darwinian natural selection. The computer makes millions of subtle changes to the design of the wing, simulates that wing in a wind tunnel, and then makes more changes. Over time, through millions (billions?) of computer simulations, a wing takes shape.

In many fields of engineering, we let computers simulate natural selection by creating millions of small changes and filtering out the good ones. It turns out that this kind of computer-based engineering generally produces the most efficient designs.

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So back to biology. The problem often cited with evolution is the concept of "irreducible complexity" -- that something is too complex to evolve because, as they say, "half an eye is useless." This doesn't apply to a brain, because half a brain is still useful (examples: bird brains, reptiles, US Presidents, etc.)

In the case of the human eye... Actually, half an eye is pretty useful -- about half as useful. Many sea creatures appear to have far less evolved eyes that are merely sensitive to light. It starts as a patch of skin that feels light, and goes from there.

All other complexity in human organisms appears to work similarly -- it started simple and grew complex over time.

Answer 2

It never ceases to amaze me that someone challenges science about complexities and then will accept the simplest, least lacking of evidence answer "that god did it".

How is "god did it" an answer? Because a book says he's omnipotent ? Why don't you ever challenge the idea of something being omnipotent?

What do you think has longer odds, the complexity of us just appearing or the complexity of god just "always being there" ?

The greater the being, the greater the odds it could have just existed

If you're going to use the logic of complexity, you can't stop at the first step, you need to take it to the farthest conclusion you can. That's how science and logic work

Answer 3

Our bodies didn't develop one organ at a time.

People attempt to use the concept of 'irreducibly complex' organisms as an attempt to disprove evolutionary theory, claiming that if you remove one part, and it causes the organism to stop functioning, that it must've been created that way - with all parts intact.

My favorite example to shut them up is an arch. If you remove any of the pieces of an arch - it falls down. Yet we all know that it was built with scaffolding in place until completed to the point that it could stand on its own.

It's the same thing that happened when over millions of years of evolution. some organisms developed new organs (through random mutations) capable of doing the same job as existing organs, which were then rendered unnecessary, and over time, were eliminated.

Complexity is not proof of creation.

Answer 4

Same explanation as anything else--millions of years of evolution. Over the course of this time, each time there were minute changes in DNA (via mutation or cross-linking of traits through sexual reproduction), those individuals which were better able to survive and reproduce passed on their beneficial genes to their progeny.

Now, I'm willing to admit that your theory, or other versions of Intelligent Design, are possible. There's just no way to test them scientifically, i.e., you can't prove that there was an unseen hand guiding evolution towards it's current manifestation. But I decline to deny such a theory outright.

Answer 5

Ultimately Complexity always derives from selection processes. Design cannot orginate complexity because design requires a more complex designer which leads to either complexity "Just Existing for no reason at all" or infinite regression, both of which are logically absurd.

Selection processes select local complexity from global simplicity.

In the case of evolution each birth/death event may act to select the existence of one individual versus another. Each of these events has the potential to add a single bit of complexity into the biological system.

In the case of our universe we have a profound selection agent: Our own existence which selected our local bubble universe among all others based on its ability to support our existence.

Answer 6

So let me get this straight. Our body works so it must be God? First off it took billions of years for humans to become, so it shouldn't surprising our bodies are complex. Next the human body is far from perfect, it is susceptible to many diseases, we have the same pipe for food and air, the pancreas is less and less useful, etc.

There are holes, and unanswered questions in science, but that just means not everything has been figured out yet, not "God did it."

Answer 7

Our internal organs are very much like a chimpanzee's. Sure, there are a few modifications, but hey, we eat more cheeseburgers than chimps. You can imagine that our line of ancestors branched off from the line that led to chimps, about five million years ago. Continuing, you might see that our internal organs are very like an Old World monkey's, but less like that than like a chimp's, so we share a line with the chimps that split off from the Old World monkeys. You can continue this line of reasoning.

Answer 8

The common structures that are modified into digestive systems, or into hands/fins/flippers/wings, show that descent with modification is the best explanation.

There are a lot of great sites explaining how seemingly "irreducibly complex" features of organism can be produced in this way. Take a look for example at http://www.millerandlevine.com/km/evol/design2/article.html
and http://www.talkorigins.org/faqs/behe.html
These pages treat such features at the cellular level, but the same points can be applied to larger organisms, and in fact can be applied to them more easily.

Answer 9

You want an answer for each and every organ, or what? This is fairly basic biology, but too long for me to answer here.

And there were *many* common ancestors - the last of which (chimps/bonobos and hominids ~5.5 mya) had pretty well all the complexities we have.

And your connection between the Big Bang and our complex bodies is exactly what???

Answer 10

You should ask this question in the science section and not here. But better read a book about it, it's a too complex matter to be answered in one answer on this website.

And yes, of course there is a theory, it's called the theory of evolution.