As a scienist, how do you see evolution and the origin of life?

Question

I want to ask this in a neutral context and get some less biased answers than I have been getting. I guess there are two questions that I have here.

1. How do you view evolution, as a fact or as theory? In school, we're taught about evolution, but the way it's taught, it can be easy to assume it's fact. However, it still has holes in it, things that can't be explained, and it can't be proven completely true or false, so it's a theory. So, why is it taught in a way that we assume it is fact? (Note that I'm focusing on macroevolution here, microevolution is a different topic.)

2. Are there any legitimate theories out there right now about the origin of life? As far as I understand, there have been some proposed theories that have been rejected by the scientific community. I also know about the Miller experiment, but that was also rejected because it was skewed to create favorable results. Is there any theory out there right now that is considered plausible by scientists?

In regards to the Miller experiment, rejected might have been the incorrect word, but objections have come from it. The initial experiment used more active chemicals that would be more favorable for creating life, but it's generally been assumed that the quantities used were not the same as in earth's early atmosphere. They believe that more inert chemicals were actually present.

That's what I had learned about. I'm doing some more reading on it.

http://en.wikipedia.org/wiki/Miller-Urey_experiment#Earth.27s_early_atmosphere

Answer 1

1. Evolution is BOTH a fact and a theory.
The problem is that, as used commonly, the singe word "evolution" is vague without clarifying whether you mean the *process* of evolution of the *theory* of evolution. The first is a fact, and the second is (trivially) a theory.

The *process* of evolution is just the process of "slow change over many generations". That's it. That's all it is. Even the most stalwart Creationist has to admit that organisms change over many generations (which is why we can breed canines into bloodlines as different as great danes and chihuahuas). The attempt to draw a distinction between micro-evolution and macro-evolution is a red herring unless you can show that they are *fundamentally* different processes. It is worthwhile to examine the process of evolution at both levels ... but there is no *fundamental* barrier between the two processes ... the process of macro-evolution is just the process of micro-evolution on a much longer timescale. In other words, it is *not* "a different topic" ... where one can be called a "fact" and the other a "theory."

The *theory* of evolution is the explanation for (a) *how* that process of "slow change over generations" occurs in the wild (namely 'natural selection'); and (b) how that same process explains the origin of all species from earlier species.

But by "theory" this does not diminish it into something "lower" in truth-value than a "fact". A theory is an explanation of facts. Thus a theory doesn't 'graduate' to a fact. A theory can never become a fact, (or vice versa). This is why we still refer to the germ theory of disease, the force theory of gravity, the atomic theory of matter, the plate tectonic theory of geology, the heliocentric theory of the solar system, and, yes, the theory of evolution. All of them are accepted with a HIGH degree of confidence ... and all of them are called "theory", and always will. The theory of evolution is no different from all these other highly-regarded scientific theories.

2. There are several very legitimate theories about the origin of life. No single theory stands out as the dominant theory (the way that natural selection has emerged as the dominant theory of evolution). But I have never heard that the Miller-Urey experiment (or any other proposed theory) has been "rejected" by the scientific community. All of these theories propose to show a limited piece of the puzzle ... e.g. how amino acids can form from raw ingredients ... how more complex replicating molecules can form from amino acids ... what the conditions for early life might be ... what are the smallest requirements to support a self-replicating molecule ... whether replication can or must precede metabolism or the other way around. It is wrong to imagine that these biochemists are proposing theories that are then "rejected by the scientific community." They are proposing pieces of the puzzle.

So *all* of these theories are considered "plausible" pieces of the puzzle. They are just continuing the research to determine what synthesis or combination of these competing (or in many places complementary) theories can move on from being merely "plausible" to being more "probable" than the other theories.

Answer 2

1. As a scientist, I accept evolution as a theory. Theory in science is different from theory in common parlance. It isn't just an idea or whim. A scientific theory is an extremely strong statement-stronger that stating something is a fact, because it has been tested many times in many ways and has been supported through these tests and NEVER falsified by tests. Remember, a scientific test of a hypothesis (say of evolution) is designed so that there could be an outcome that will refute/falsify that hypothesis if it is false.

2. To build on what you asked about the Miller experiment, the pitfalls of that experiment were that they used the incorrect gases to simulate the atmosphere 4 billion years ago. Similar experiments have been done again with the appropriate "picture" of what the atmosphere and oceans were like chemically and physically given our more recent knowledge. We have seen protein synthesis and replication in similar ways to that of the Miller experiment in these new experiments.

What we now know is that the origin of life required environments that provided: 1. concentration of compounds and minerals essential for life and 2. enough energy for the reactions. #2 isn't a big dea. #1 means that the environment was probably someplace that experienced cyclic episodes of drying and wetting, much like tidepools on a rocky shore.

Answer 3

1. Evolution is a FACT and DNA proves it. To say that it is "only a theory" is to misunderstand what the word "theory" means in science - an extremely well-documented set of evidence leading to an overwhelmingly obvious conclusion. Just because there are some things about evolution that aren't known (and some might never be known) doesn't mean that the 200,000+ scientific papers submitted on the subject don't prove anything. Gravity is a theory too - think it doesn't exist because it is "only a theory"?

2. You are talking about "abiogenesis" and it is different from evolution - it is a separate concept. After life started, THEN evolution happened, but with no life happening no evolution could have occurred because life has to exist first. The Miller-Urey experiment was NOT "skewed" (where are you getting this information from???) and in fact had a flaw in it in that it INCLUDED water in it but the primordial atmosphere would probably have had very little or NO water at all - how is that being "skewered" to give a favorable result?

Answer 4

1.The most important thing you must know about a Scientific Theory, is that a Theory is held as fact. Of course something could come along and disprove evolution, no one can every know if it 100% ture. However we know that it is 99.9 true. There could always be something new to be discovered. But until then Scientist take Theories (in their correct definition) to be held as fact. Like in physics, ideas (notice not using Theory) all build off of the Theory of Relativity. Physicists may never know if Relativity is correct, but the assume that it is. The same goes for evolution. Something could come along and prove evolution wrong but for now we hold it as fact.

So evoltution is a Theory, but a Scientifc Theory is much different that the laymens definition for Theory. Meaning that Evolution is considered a fact.

2- I heard of a few explinations. One is about RNA, the other is about bubbles forming and being like early cells. Wikipedia has more on it.

Answer 5

1. I definitely view evolution (both micro and macro) as a fact. Most people will mention fossil records and other archeology findings in their explanations of their beliefs in evolution. There will obviously be "holes" in the fossil record because of the extreme number of circumstances that must occur in order for an organism to leave behind a fossil. While the fossil record is indispensable to forming our current understanding of evolution, the science of molecular clocks is in my opinion stronger evidence that organisms share common ancestors. This requires some knowledge of DNA and how it becomes mutated to understand though, so most people haven't even ever heard of it much less know what it means. Briefly: Every time a cell divides it must copy its DNA. When the DNA is copied there is a small amount of mutation that occurs. The frequency of this mutation rate is for the most part constant. So therefore if we make predictions as to how long ago two organisms "split" then the amount of mutated DNA between the two should reflect that time. There are multiple examples of the time line predicted by the fossil recored being in agreement with the time line predicted by molecular clocks. This would seem to be an extreme coincidence in a world where organisms do not evolve.

2. I don't really know enough about this to give a strong answer.

Answer 6

I don't know if it's a fact, but it seems to be the best theory around, certainly better than biblical creation.

As to intelligent design, the intelligence does not always have to be God, as described in the bible.

The latest theory I have heard is that clouds in interstellar space mix around for billions of years, creating amino acids, when these land on early planets, life might be formed.

Certainly if early life was transplanted here by another race, that's how it got here.

If either is true, it is entirely possible that life is everywhere in the Universe.

It is certainly here, no this planet, and there are billions of planets in this galaxy.

With millions of galaxies in the universe, there's a lot of life out there.

I don't think life is a one in a billion thing, otherwise we are certainly too rare to be fighting amongst each other like we do.

AN INTERESTING QUESTION, CERTAINLY.

Answer 7

1. It is a theory. That being said, look up what a theory is. It is a supported hypothesis that have been shown to be true.

2. Abiogenesis is the study of the beginning of life. This is much harder to make theories on because there is no evidence of it left over. But all the logical, science based hypothesis's have something to do with either spontaneous generation, or life coming from another planet.

Answer 8

Not sure why you believe the Miller experiment was "skewed" or "rejected", it has been reproduced & repeated so many times since that it is clear that production of some quite complex organic molecules in the lab within the space of a few weeks is EASY...

Evolution is a "Theory", not a "theory", there's a big difference!

Answer 9

Here are a couple of sites by scientists, if you want to continue reading:

http://www.ucmp.berkeley.edu/

http://www.newscientist.com/channel/life/evolution

It's one of the best established ideas in science. The evidence comes from a broad range of areas. (There's a thing at the first site that addresses the lines of evidence supporting evolution.)

The word "theory" in science, as in Newton's Theory of Motion, does NOT mean unsupported, questionable, or shaky.

It refers to a body of thought, lines of reasoning, and evidence -- the product of intellecutal work.

NOT the ordinary use of "I have a theory why Ed yelled at us" that means "guess".

It's a body of knowledge, concepts, reasoning, supported by evidence.

Holes?

You mean they haven't yet figured out ALL the details?

Well, that's true of every science where there are active scientists working.

That's not a flaw.

As for the origin.

There's an idea: emergence something (sorry -- I heard about it on a recent PBS NOVA show -- you could check them out; find the segment about birds flocking and fish in schools; it also addresses how this may be relevant to understanding how life started).

Origin of life is separate from Darwin's evolution through natural selection; he "started in mid-story" as it were.

The fact that we don't YET know how this happened is irrelevant to all we know about what happened after life first started.

This is what evolution is all about.

The reason I, personally, hesitate to call evolution "fact" is that seems to me to apply to single bits of information, rather than a whole big structure, as evolution is.

The cat is eating, is a fact.

Evolution through natural selection working on mutations is an explanation.

It explains the diversity and adaptation of species.

You might also be interested in what I wrote in my 360 blog entry on evolution.

Now, if you're sincere, I hope you pick one of the evolution-based answers, since that who you're asking. (Sorry, but I've spent hours and hours carefully answering questions from people claiming to want to understand, who then ignore all the explanations they get and chose "it's all hooey" answers.

Oh, a warning about the New Scientist site. It's the web version of a magazine.

Some of the linked items you'll see if you go to the page are free; others are just the first bit, available only if you buy the magazine.

So ignore the ones that ask for money, and read the freebies. (That's what I do.)

The U.C. Berkeley one is free.

Oh, and I'm not a scientist. I find it really interesting and helpful and have read and watched quality documentaries on the subject, but am an educated lay person, not a working scientist.

Answer 10

It seems like obvious fact. I am as convinced as I am that the sun's energy source is nuclear fusion. I will never get to ladle out a sample for analysis though. Evolution makes intuitive sense.

I went into a concrete tunnel, constantly damp since its construction in the '20s. There were stalactites and stalagmites. I thought "In only 80 years, this thing has morphed in a way you would never expect!" Think of subtle effects accumulating over 1000 years multiplied by 1000 again and then 100!