I don't think anyone would dispute that finding, still doesn't convince me of evolution. Like I said there seems to be a lot of information out there and findings, but until someone pieces it together, I am not accepting it.
Can an expert explain Evolution to me?
- Thread starter Galactus
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I don't think anyone would dispute that finding, still doesn't convince me of evolution. Like I said there seems to be a lot of information out there and findings, but until someone pieces it together, I am not accepting it.
How does that even make sense? You knew there's evidence out there, but until someone puts it in a neat, easy to understand, evolution for idiots style bundle for you you're not going to accept it?
What we find are distinct species -- not evolutionary intermediates.
I think the bit I've bolded is a misleading concept which down to a point of view that even Darwin disagreed with: there is not such thing as an "intermediate" form. That statement assumes that an animal was heading towards a goal that may be an extant organism, but this is not necessarily the case. We can see changes in certain fossil lineages, but each one of the organisms was a separate species on its own and successfully adapted to its environment; not some kind of imperfect version of something to come.
Not trying to pick on you Jadzia; just an observation I want to clarify because the problem with a lot of would-be debunkers is that they try to use the absence of a clear line of intermediate forms as a way to attack evolutionary theory.
The bottom line with evolutionary theory is that it's based upon an incomplete fossil record. That cannot be overcome; nevertheless what we do have is very compelling. If you want to see evolution in action you need only look at the examples others have provided or animals under pressure like the Tasmanian devils which are breeding earlier in response to a lethal cancer that's killing many before their normal breeding age or moths in the 19th century which had been white and changed colour to match the change in tree bark colouration due to industrial pollution.
I want to also comment on molecular biology. It is fashionable amongst some scientists to consider palaeontologists something akin to stamp collectors (the astrophysicist who was instrumental in the research on the K-T extinction pointing to an impact from space said this exactly) who will one day no longer be needed as "real" science using "proper" techniques will render them obsolete. Molecular biology has been cited as this very thing, but it's a bit of a panacea and greatly overstated. It is indeed useful to a degree, but clearly given the state of fossilised DNA it's not as applicable to long-dead organisms; if you look at extant organisms like whales, where molecular analysis has been used to demonstrate affinity to bovines, proboscidians and suids with no clear-cut answers, I think people are getting a bit carried away.
The way I look at it, every stage is an intermediary stage. There's no goal, there's no finished. If a species stops evolving it's because it fits its niche, if new pressures come about it will adapt or die. So every stage is an intermediary.
If you want something that's between mammal and lizard? How about the platypus? It doesn't have live births, it has leathery eggs, it excretes milk, but doesn't have teats, it just excretes it through pores.
If you want something that's between mammal and lizard? How about the platypus? It doesn't have live births, it has leathery eggs, it excretes milk, but doesn't have teats, it just excretes it through pores.
What we find are distinct species -- not evolutionary intermediates.
there is not such thing as an "intermediate" form...
Not trying to pick on you Jadzia;
You know I agree with you. But yes, I can see how it could be misleading for some readers. It's a term I use to describe the state of being "between niches", as Bob put it, where some change is proving to be beneficial.
It's only really with the view of intelligent minds that we can look at the bigger picture and say "Yes, this change is a beneficial change, and we expect it to continue."
I know we both understand one another here. (secret
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I think one of the problem with those sorts of discussions is that half of the debaters don't understand the terminology.
They think that "theory" means "an idea that someone has" and that "fact" means "this is true". This in turn means that it's difficult for them to understand that evolution can be both fact and theory at the same time.
They think that "theory" means "an idea that someone has" and that "fact" means "this is true". This in turn means that it's difficult for them to understand that evolution can be both fact and theory at the same time.
Evidence does not equal fact. I think Sean said it best. There are a lot of reasons to believe that evolution occurs, but that does not make it true. If you are saying that different species have changed over time to adapt to their environment, that is one thing. To say that a water creature evolved to walk on land and no longer breath water is another. It is the latter that I hear and read about all the time and the one that I do not believe evidence supports, because there is still much debate about the facts.
This is not my field of study, so I am a layman, I just read the books like so many other people. I just am not convinced.
The whale evolution story is an interesting example of the molecular and morphological approaches. A decade ago paleontologists would have favored the evolution of whales from a group called Mesonychids (belonging to the Condlyartha, a paraphyletic mixed bag containing the ancestors of both modern ungulate groups). But the molecular phylogeny said that whales were Artiodactyls (even-toed ungulates), so there was a bit of a contradiction at the time. But since then discoveries in Pakistan have revealed the ankle bone of the early whale Pakicetus, which is an artiodactyl ankle. And there have been more fossil discoveries, including a genus called Indohyus which looks a lot like early artiodactyls like Diacodexis but has some very early whale-like ear characters. It's turned out that whale evolution is becoming one of the better examples of the step-wise evolution of a very different body plan (the other, bird evolution from theropods, is really amazing).
-MEC
Because evolution does not happen like that, things don't suddenly change. It's not one day one thing, next day another. Or even one generation one thing, next generation another. You don't go from fish to land animal. You go from fish that can only survive in water, to fish that can hold it's breath, to fish that can hold it's breath for longer, etc. then you get to the point where the food is running out, and the fish has to go on land to find something, because it can hold it's breath for a long time it starts going on to land, and the fish that can push itself with strong fins has an advantage over the one that can't, and the stronger fins, and the higher amount of time out of water makes a big difference to it's family. They survive and pass on those abilities, after many generations of this the fins start to become rudementary feet.
You wanna see an example of something like this? The lungfish.
Hi Galactus.
What if a computer simulation was given to you?
I don't mean the kind of tricks used in computer games, but a simulation which created life forms from a universal genetic code. There are no rules to what the code can create, as it is designed to work in much the same way as DNA, able to describe all kinds of trees and mammals and bees and fish like creatures.
Then we set up a colony of life forms, and allowed random mutations in offspring, allowing competition and conflict and other things relevant to survival. And you saw in the simulation not only environmental adaptation through successive generations, but slowly over time also creatures are found migrating from one environment completely, like water swimmers with gills, eventually becoming land walkers with lungs... would that be more convincing?
I'm not saying that I know what the outcome of a simulation would be, as I've never tried to make one, I'd just be interested to know how you'd interpret that as evidence supporting evolution or irrelevant?
Thanks for the update. I hadn't realised that Pakicetus had led to these disparate findings coming together. Is there consensus on that? I think we would both agree that morphological analysis that supports molecular analysis shouldn't be used to discount (or worse stop funding research) of the former.
Hey, I just read your location -- you in Santa Cruz? I'm a Porter College graduate '92.
To anyone interested I'm presently reading Peter D. Ward's book Out of Thin Air in which he lays out the controversial (but I have to say pretty compelling) theory that the primary mover in the evolution of the body plans of all animal life on earth has been respiration; more specifically extraction of oxygen in the atmosphere. He takes each era and looks at land and sea life and oxygen levels. This is a mass-market hardback for lay people, but he's submitted actual papers on it. He's done principal field research on both K-T and P-T extinction events and is a great writer generally. He starts out with the biology of how animals use oxygen then discusses body plans, what data was used to determine oxygen content of the atmosphere in ancient times and then goes through each area describing what the atmosphere was like, what it looked like and the morphology of animals in the sea and land at the time. It's only a few hundred pages and has a few black-and-white illustrations.
I found him purely by accident when I picked up a copy of Gorgon at a charity shop in a small Scottish town which is also a great read about his field work on the Permian extinction in the Karoo in South Africa. It covers not only how he came about his theory on the cause of the Permian extinction, but gives an uncensored view of what palaeontological field work is like and what South Africa was like before and after the end of Apartheid. At the end he gives a hint at Out of Thin Air when he muses that the success of the dinosaurs was probably down to having a body plan that is more adapted to living in a low oxygen atmosphere. I then went on Amazon to see if he had published anything since and found this.
Brilliant stuff.
Indeed from the fossil record it looks like we had fish with arms and legs before those fish could even breathe air and there's evidence that tetrapods left the water and failed to take a foothold; so there's probably been some regression along the way before we even got fully-functioning land-living vertebrates.
The lines aren't straight. Denying evolution in the face of the mountains of evidence, well, I really think The Devourer of Worlds needs to get down to a library and do some reading before I can take his position seriously. The Origin of Species was written for the public; it's quite readable and spelled out in a manner that is very understandable using first-hand and second-hand observation as well as logical reasoning.
It's important to note that even in Darwin's time scientists were accepting of evolution; it was more Natural Selection as the mechanism that was controversial...
Galactucus, it sounds to me like you need an understanding of logic more than you do of evolution.
You have admitted several times that not only are you a layman in the field of evolution but that you have an unscientific mind. That being the case, OF COURSE you don't understand evolution. I'm betting you don't understand quantum physics or relativity either. Does your ignorance make those things any less real?
You have essentially admitted that you are entirely unqualified to determine whether evolution is true or not based on scientific evidence. You don't know what to do with the evidence. That doesn't just go for you; It probably applies to most everyone on this board.
We have to defer to experts in areas where we are only laymen. That is so easy to do regarding evolution. It is an old field that started off as very controversial. It has been the subject of enormous amounts of study. Over the decades, mountains and mountains of evidence in favor has piled up - with no evidence against. The people who DO understand evolution are nearly unanimous in their agreement and they continue to turn up more and more evidence.
To "not buy" the claims of scientists regarding evolution, you would have to think they are fools or are in on some wildly-improbable worldwide conspiracy to hide the "truth of our origins". There really aren't any other alternatives.
You have admitted several times that not only are you a layman in the field of evolution but that you have an unscientific mind. That being the case, OF COURSE you don't understand evolution. I'm betting you don't understand quantum physics or relativity either. Does your ignorance make those things any less real?
You have essentially admitted that you are entirely unqualified to determine whether evolution is true or not based on scientific evidence. You don't know what to do with the evidence. That doesn't just go for you; It probably applies to most everyone on this board.
We have to defer to experts in areas where we are only laymen. That is so easy to do regarding evolution. It is an old field that started off as very controversial. It has been the subject of enormous amounts of study. Over the decades, mountains and mountains of evidence in favor has piled up - with no evidence against. The people who DO understand evolution are nearly unanimous in their agreement and they continue to turn up more and more evidence.
To "not buy" the claims of scientists regarding evolution, you would have to think they are fools or are in on some wildly-improbable worldwide conspiracy to hide the "truth of our origins". There really aren't any other alternatives.
Jadzia
It would be nice to see, but I am not sure what effect it would really have on me. I have seen models that were supposedly done to show for example what a humanoid dinosaur would supposedly look like. I don't think it would really change my mind.
Bob The Skutter
That is exactly how evolution is suppose to occur I just did not list all the steps. Jadzia just talked about a computer model that would show all the various "stages" a species would go through. In your example you did not even start at the begining which would be some sort of bacteria.
StarryEyed
I don't think I ever said I don't have a scientific mind. I actually work with some of the brightest minds in science who come to me for help in my field of expertise. For example I have a very good friend who works in astronomy and he does not believe in evolution. To say their is a consensus is not true either. Each generation of scientists, basically says the previous one has got something wrong because they found new evidence. I have no doubt there will be a new break through that will totally rewrite what we know today. The only I can say people agree is that evolution occurs. What that actually means is up for discussion.
It would be nice to see, but I am not sure what effect it would really have on me. I have seen models that were supposedly done to show for example what a humanoid dinosaur would supposedly look like. I don't think it would really change my mind.
Bob The Skutter
That is exactly how evolution is suppose to occur I just did not list all the steps. Jadzia just talked about a computer model that would show all the various "stages" a species would go through. In your example you did not even start at the begining which would be some sort of bacteria.
StarryEyed
I don't think I ever said I don't have a scientific mind. I actually work with some of the brightest minds in science who come to me for help in my field of expertise. For example I have a very good friend who works in astronomy and he does not believe in evolution. To say their is a consensus is not true either. Each generation of scientists, basically says the previous one has got something wrong because they found new evidence. I have no doubt there will be a new break through that will totally rewrite what we know today. The only I can say people agree is that evolution occurs. What that actually means is up for discussion.
Yeah, the discovery of the ankle bone (astragalus, specifically) of Pakicetus was one of two papers published in 2001 that really cemented the artiodactyl relationship. I didn't read up on the molecular stuff too much when preparing the lecture, but I think that hippos may be the closest living relative - although they all diverged very early in the history of ungulates.
I am at Santa Cruz. But the colleges don't really mean much to me, except when I get calls from the students' college advisor if something goes wrong and they miss an exam (such as falling into one of the quarries - seriously!). Not all professors belong to a college anymore (I was never encouraged to become affiliated with a college), and we actually give out letter grades now!
And Peter Ward's hypothesis of oxygen levels is quite compelling, I think. Bird-like flow-through lungs with supplemental air sacs in the vertebrae were present pretty early in theropods (and perhaps all dinosaurs), which would have given them a competitive advantage at the low oxygen levels found in the early Mesozoic (perhaps as low as 12-15% rather than 21% today). And other features like the perhaps aborted colonization of land by tetrapods (Romer's gap) also seem to correspond fairly closely with oxygen fluctuations.
Yes, air-breathing and limbs evolved before those early tetrapods could walk on land. The vertebral column, shoulder, and arms of early tetrapods like Icthyostega wouldn't have been sufficient to actually support locomotion on land. So the traditional view of lungfish flopping from one drying pool to another and gradually evolving limbs probably isn't correct - rather it seems likely that limbs evolved to help the organisms navigate through tangled vegetation in the swampy Devonian rivers, perhaps for predator avoidance or better hunting. Then those limbs were later co-opted for locomotion on land. That kind of co-option seems to be fairly common, as it occurred with feathers (evolved in theropod dinosaurs before they could fly) among other things.
The implication that we cannot trust scientific evidence for evolution (or other topics) because future scientists may overturn that evidence is a futile argument, I think. It is true that scientific revolutions have significantly revamped our understanding certain fields at various times in the past. But does that mean that I shouldn't agree with astronomers that the Earth revolves around the Sun, because future astronomers may find something that totally rewrites what we know today? I think it's safe to say that some topics are "mature" and are unlikely to be revolutionized (the heliocentric model, for example) whereas others stand a good chance of future revision (the standard model of particles, perhaps?). I would say that evolution is nearly certainly in the first category, as the evidence is largely based on some fairly traditional and long-standing fields of science (paleontology, biology). Also, the evidence for evolution comes from a wide variety of fields, making it much less likely to undergo a revolution in thinking.
I guess I meant I don't have a scientific mind, 
.
I was trying to say I was not a scientist, so I guess they are one in the same.
I don't think all minds in the field think alike. I mean tell me what the consensus is. The reason I started this thread is because I don't know. Educate me.
.I was trying to say I was not a scientist, so I guess they are one in the same.
I don't think all minds in the field think alike. I mean tell me what the consensus is. The reason I started this thread is because I don't know. Educate me.
You believe a single species can evolve to suit changes in its environment, say in X years.
So, take that species, and divide it in half. Put the two halves in radically different (survivable) environments. After X years, they've each evolved----but in different directions. With luck, they may still be able to interbreed, but they could lose that ability as well given time.
Now divide each of those subspecies in two again. And again, and again, every X years. After 1000000X years, that single species has spawned 2^1000000 subspecies; the most different of those may not even be recognizably similar.
Does that help you grasp how evolution could allow for radical changes such as fish->zebra, at least a bit?
So, take that species, and divide it in half. Put the two halves in radically different (survivable) environments. After X years, they've each evolved----but in different directions. With luck, they may still be able to interbreed, but they could lose that ability as well given time.
Now divide each of those subspecies in two again. And again, and again, every X years. After 1000000X years, that single species has spawned 2^1000000 subspecies; the most different of those may not even be recognizably similar.
Does that help you grasp how evolution could allow for radical changes such as fish->zebra, at least a bit?
I guess I meant I don't have a scientific mind,
I was trying to say I was not a scientist, so I guess they are one in the same.
I don't think all minds in the field think alike. I mean tell me what the consensus is. The reason I started this thread is because I don't know. Educate me.
Nearly all scientists in the field agree that it is a fact that evolution occurred. The mountain of evidence is simply undeniable. The exact mechanisms for it is very much an open book.
You really want to get educated? Spend some time here: http://www.talkorigins.org/
The mechanism are up for discussion at a very fine and high level - the idea that there is no consensus on evolution is creationist claptrap, it's something they have pushed for over 100 years with no success.
That's like saying your plumber friend doesn't agree with your mechanic. Astronomy and Evolutionary Biology are 2 entirely different science. Because someone is a scientist it doesn't make them an expert in all branches of science.
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