Gravity and evolution

But knowing exactly WHAT it [gravity] is, is still up for grabs.

I thought the principle of gravity was simple: All matter in the universe exerts a pull (aka, gravity). The greater the mass of an object, the greater the pull. This is Newton's law. Prior to Newton, people observed objects falling towards earth, but had no concept of gravity being universal.

 

Galatian observes:
Gravity was not "known" for many centuries. It was observed that things fall down when nothing stops them. However, gravity was first hypothesized by Newton, who showed how it worked and that it could account for the motions of planets. Likewise, we see variation within and among species. Darwin only discovered why it works, and showed that it could account for common descent.

So were the effects of evolution. But gravity (as opposed to the effects of gravity) wasn't "known" until someone could come up with a theory to explain it.

Newton. You see, the fact that people knew things fell toward the ground didn't mean that they "knew" gravity, any more than the observation of variations that were more or less fit meant that they "knew" evolution.

Newton explained what it was, and showed how it worked. Then we "knew" gravity. Before that, no one had any notion that the same forces that make an apple fall from a tree make the moon move in orbit.

When do you think the word "gravity" appeared?

Wrong. No one associated the movement of planets with gravity. Even Kepler, although he was able to formulate a law describing that motion, did not know why it happened. Newton explained why, in a general theory of gravity. (this, BTW, is an illustration of why theories are more powerful and useful than laws)

Yep. People had noted for a long time that variations occur, and that they can accumulate over time to make a change in the population. Animal breeders were quite familiar with that. Darwin's insight was how it worked to make new species.

Last I heard, the ICR admitted that even new families evolve. In an e-mail, John Woodmorappe of "Ark Feasibility Study" fame told me the same thing. If creationists back up just a little more, we won't have anything to argue about.

Anyway, there are a good number of new species directly observed to occur in nature, so the "only by design" idea isn't viable, either.

 

Einstein pointed out that it is due to the affect of massive objects on space. When one does the math, the affect of such masses precisely matches the effects of what we call "gravity".

But so far a complete theory of quantum gravity still eludes scientists.

Barbarian observes:
The effects of gravity were certainly known for many centuries. Gravity, on the other hand, was not "known" until Newton.

So were the effects of evolution. But gravity (as opposed to the effects of gravity) wasn't "known" until someone could come up with a theory to explain it.

Not completely, but I'm pleased to hear that you think they are similar in the degree to which we understand them. There's still a lot of important questions to answer. However, what we do know about gravity and evolution has a number of important uses. Drug protocols, for example, agronomy, and breeding, and even predicting what antibiotic resistance might be next:

http://www.rochester.edu/College/BIO/labs/HallLab/

Microgravity, you mean. You've never actually seen a galaxy pulled together by gravity.

Other than the many examples we've shown you on this board.

Barbarian observes:
Newton.

Nevertheless, he is considered to know something about it.

Barbarian observes:
You see, the fact that people knew things fell toward the ground didn't mean that they "knew" gravity, any more than the observation of variations that were more or less fit meant that they "knew" evolution.

Assuming that you think fish with legs and dinosaurs with feathers are consistent with their "basic type". "Basic type" is not a scientific term, so it's hard to say what you mean by that.

 

There is no need nor reason to make physics appear inaccessible by mystical invocations of "we don't know what ... is." Of course we do not know, in an ultimate sense, what gravity is, nor what electricity is, nor chlorine, nor the Mona Lisa, nor Abraham Lincoln, nor my dog, nor what any of us is, nor the ultimate nature of God. That doesn't stop us from talking about any of them, nor does it mean that we do not know a great deal about any or all of them.

Galatian has already briefly discussed what gravitation is at one level of phenomenology. One could go into it more deeply. As explanation unfolds we can, as linteners, after respectful pause, enquire further and deeper into ta subject, mindful that at some depth our collective wisdom and knowledge will not hae penetrated. When we reach that sublime depth we behold on the one hand all that we have learned of a subject (gravity, for example, its universality, the equivalence principle, gravitational field as metric of space-time, and perhapsome (as yet speculative) ideas on quantum gravity.) And on the other hand we shall have an informed wonderment that we cannot (at least now) penetrate our subject more deeply. One steps atop the precipice between our vast (for it cannot be underestimated) knowledge on the one side and the gulf of our ignorance the other side. It's a dazzling sight, but only if one has taken the trouble to understand the nature of our ignorance by first enquiring into our knowledge.

Anyone with his or her head stuck in a paper bag can say "we don't know what it is" about anything; but to make that a theme of discussion is mere Know-Nothingism. A pronouncement of what we do not know is uninteresting unless accompanied by something of our efforts to know

 

You see microgravity. But neither you nor any other human has ever seen a galaxy form by gravitational attraction. Don't give me any excuses that humans don't live that long. If it can't be directly observed in a human lifetime, it can't be true! (warning for the humor-impaired)

The evidence shows that the jump from prokaryote to eukaryote took longer than anything else in life's history. So that's not a problem, if you know the evidence.

Such as a fish with legs?

http://www.palantir.fsnet.co.uk/acanthostega.htm

http://www.gate.net/~rwms/EvoLimb.html

The evidence is voluminous, but is mostly:

1. Fossil record, showing many transistional stages in many lines.

2. Later DNA analyses that show precisely the same phylogenies as independently found by anatomical methods.

3. Numerous biochemical analyses which gives the same results, albeit at a lower resolution, due to more highly-conserved molecules.

4. Directly observed evolution of irreducibly complex features.

5. Predictions of the sort of fossils that should exist, based on evolutionary therory, being found at a later time.

As we discussed earlier, many workers use evolutionary science in their daily work, and their predictions based on it are often validated.

 

It is observed to the extent that gravity is observed. We can observe the processes that are sufficiently brief to occur in our lifetimes.

To say that any process that lasts longer than a human lifetime is not possible is absurd. You seem to understand this for such effects due to gravity, but cannot get this fact when it comes to evolution.


It is therefore not in the same class. To claim it is observed it is necessary to invoke variation, which no one is arguing about anyway!

 

No kidding the evidence is that eukaryotes took about a billion years to evolve. Apparently, a very difficult thing to do.

Other than the fossil record, genetics, paleontology, observed evolution, etc.

I'm just responding to your argument. If you didn't want to talk about it, why did you bring it up?

You toss out so many interesting things in a string, it's hard to ignore them, Helen.

 

Did I ever tell you about the time I was a kid and I was talking to my mother about the hands on the clock? I told her the hands on the clock were not moving, I could just see they were standing still. She told me they were moving, only moving to slow for the human eye to notice the movement. I just didn't believe here as a child, but as an adult I know she was right.

Its the same with evolution. We see about the amount we would expect to see in the time we have seriously been watching for it. It's unreasonable to ask for evolution to move faster than its natural slow pace.

 

Well, if you put the bacteria in the same environement they are suited for and let them breed, they won't change. You alter the environment, and the bacteria will evolve to suit the environment. It's a routine thing to breed bacteria to have resistance to an antibiotic they originally couldn't resist. Much to our dismay, they're doing it outside the laboratory! So yes, we do see the hands move a little across the clock of our era . . .

 

Not that this has much bearing on the conversation, but Robert Pirsig (sp?) argued from this standpoint. Actually IIRC his standpoint was "did gravity exist before Newton". Again, this doesn't have much to do with the conversation as Pirsig was on a completely different track when he brought up gravity in "Zen and the art of Motorcycle Maintainence".

 

OK Back to the theme of this thread, which is something to the effect that gravity is a well known truth but evolution is not.

First of all, regardless of the true facts about evolution, I think we can all agree there are a wide variety of opinions out there about evolution. In the minds of some, gravity and evolution are equally certainly true. In the minds of others, gravity is true and evolution is not.

Secondly, we misunderstand when we say gravity is directly observed and evolution is not. We do see things fall - but it is not always true that we see things fall. Just the other day I saw some balloons fighting their strings to rise higher. In my mind I see this as being consistent with gravity. But there is a certain level of inferred relationships and accepted principles involved to make that reconciliation in my mind. When it comes to accepting that Pluto is bound by gravity to the Sun just as the earth is, in my case, that's almost completely a faith kind of thing. I've never seen Pluto in my life! So I take the word of others.

Is this an unreasonable thing for me to do or is it reasonable? Why is it reasonable for me to believe Pluto the planet is really out there? Why do I follow with interest the debates as to whether it properly meets the definition of a planet?

So I say gravity, too, is an inferred, abstract thing that we accept based on evidence but it is still an inferred, abstract thing.

Evidence, folks, it all comes down to evidence.

 

To add to Paul of Eugene's post:

In this thread I posted this:

 

Hard to explain the evolution of a system to metabolize nylon, as a hot spot, since it's never been seen before, and because it happened as a frame shift, which is not mediated by "hot spots".

Nor can Barry Hall's experiments be attributed to hot spots. There's a lot more to evolution than you suppose.

There are many antibiotics found in soil. The "fresh earth" smell you get when working in the garden is from Streptomyces, from which streptomyacin was obtained.

Actually, it seems to go by fits and starts, mostly caused by changes in environment.

As you saw earlier, genetics is one of the primary sources of evidence for evolution. DNA analyses show the same phylogenies as evidence obtained early in anatomy and fossils. And we know it works, because the same analyses can be used to demonstrate the ancestry of known groups in people and other organisms.

Even the errors and glitches point out common descent. For example, humans have one less pair of chromosomes than chimps, even though our DNA is 95%+ similar. But one human chromosome looks precisely like two chimp chromosomes linked together. And in that human chromosome are the remains of telomeres that tell us that it was once two that fused.

http://www.gate.net/~rwms/hum_ape_chrom.html

Fossilization, for most organisms, is a very rare thing. Nevertheless, we do have very finely detailed sequences in a number of organisms. Can we talk about some of them?