Geology of the National Parks

Video Lecture


The Unit 11 lecture features Dr. Richard Alley and is 50 minutes long.

Unit 11 Lecture
Click for a transcript of the Unit 11 lecture.

This time we're going to talk about evolution and extinction. This is a fascinating story. It builds out of the histories that we have been discovering in the rocks. It clearly is related to putting the fossils in order. It also clearly is, for some people, a hot button issue. And so I thought it might be useful to chat a little bit first, to show you what some of your classmates think.

And so as we've taught this class over the years, we've run some surveys and we've asked questions of various classes. And so I'd like to walk you through the survey. Now we did something interesting with this. We had two sections of the class. And we asked essentially the same questions of both sections, but we worded them differently. And so I want you to see, sort of, what happens when you tweak with people's minds in the survey.

And so we did this with these two different ones. Sometimes we asked a question, and we said you have to agree or disagree. You cannot be uncertain. And then we'd say, OK, it's all right now. You can be uncertain if you'd like, and you'll also watch this come bouncing through. And so we started off with basically a statement of evolution, but evolution as it would apply to humans.

So the statement was; well understood biological processes caused evolution of modern humans from an ancestral population of ape-like creatures that is also ancestral to modern chimpanzees. So some ancestor splits, and we get chimps and we get us. So this is, sort of, the modern statement of evolution as it would apply all the way through. And so we asked the group, and we said, OK, what do you think about this? 2/3 said yeah, yeah, yeah, I believe in the science. I believe in evolution. So they agreed.

A third disagreed. When we allow them to be unsure, you'll notice that the numbers changed a lot. And in fact, immediately it pops to the majority being unsure. They're not sure what they want to do about this. Yeah, OK. Now we tried this same question with the other section only we've worded this a little differently.

So this is also a statement of evolution of a sort, and we said, OK, you've got some biologists. They're out there. They're trying to feed you. They're trying to cure you. That's great. And as soon as they start talking about gene frequencies, they're evil liars or else they're completely lost. They don't get anything right. They cure you of diseases. That's fine, but when they talk about your genetic frequencies, they're total morons. OK, now there are.

So when we worded it this way-- it's the same question essentially-- actually virtually everyone disagrees with it. There still is something like 10% of people who, sort of, think that, yeah, biologists don't know what they're talking about or else they're evil liars. But most people you word it this way, then they say, yeah, the scientist, sort of, know what they're doing so we probably ought to stick with that.

OK, so we go back and we say the second law of thermodynamics forbids evolution as proposed by Darwin and followers. OK, the second law of thermodynamics is things sort of get messed up over time. You can't-- you can't quite break even when you're doing something. You need an energy source to make things work. And when we put this out, a third of the students said, yeah, second law completely forbids evolution. When we allowed them to be unsure, virtually everybody gets unsure. They say, wow, wow. I don't know about this one.

In fact, there are young earth creationist groups who have told their followers don't use this argument. It's so stupid. It's so wrong. There isn't any chance that the second law of thermodynamics forbids evolution.

What it says is, if order appears someplace, it has to mess up something else. And so, in turn, you freeze water, you get a snowflake. And that's more orderly, but what's around that gets messed up. But that's all the second law says. And so this is completely wrong, and like I say, some of the young earth creationist groups even say come on. That's really stupid. Don't use that one.

And then we tried a different one to the other class. We said the law of conservation of information forbids evolution. Now this is something that has been made up recently. It is not scientifically accepted. There's no real basis of a law of conservation of information. But in fact, we got exactly the same answer for this one and as we did for the second law, which is a third of people say, yeah, this does. And when you allow them to be unsure, then they're unsure.

OK, let's walk a one through. This one may be more interesting. The complexity of living organisms demonstrates that an intelligent designer was involved. This has been a hot button issue for the last few years with people saying, well, we're not going to teach religion in the schools, but we're going to teach this. And scientist saying, no, what you're really doing if you try to teach this is teaching religion.

And so this one that you look at the complexity of living things and you see an intelligent designer, in fact, 2/3-- almost 2/3 said yeah. You look at the complexity of living organisms, and that shows an intelligent designer. When you allow them to be unsure, a majority still go this way. Now if we phrase that differently though. If we say, OK, the complexity of living organisms demonstrates that an intelligent designer such as a space alien, the flying spaghetti monster, or the deity or deities of some religion or religions was involved, actually the support goes down a good bit and most people now disagree with this idea.

And so, sort of, putting a flying spaghetti monster or a space alien really reduces the support for this particular idea. And so I hope you can see that, first of all, the way one asks these questions makes an immense amount of difference. In fact, the most important thing in there was not what I was asking about but how I asked the question, which is interesting. And so in turn, when you see anybody putting out their poll showing that the public believes with them and disagrees with the other people, you should be very, very careful. Because how these questions are asked completely controlled what we were getting when all is said and done.

And so I think it's useful to be skeptical of some of these things. And let's face it that not everyone has devoted their lives to understanding the technical issues, and so there's a lot of uncertainty floating around on these things with the technical issues. And I will chat a little bit more about this in a bit as we walk through some things. This is a hot button issue.

As we walk through this, I want you to remember where we started with science. And that is that science is not truth with a capital T. Science is the best we humans can do at coming up with explanations that successfully predict what happens. And we always know that we could make mistakes, and our students could figure out what we've done wrong and could improve on it. And so as we go through this, please remember that. Because by the time we get to the end, we should have gotten to some things.

So with that as a background, let's look at a national park, a national monument in this case. This is a really cool one that nobody goes to. This is the Florissant Fossil Beds, and it's sitting, sort of, outside Colorado Springs. And it has-- as you can see in the picture, it has big petrified trees, really cool petrified trees if you get into that. It is-- the Rockies are right behind it, so you go in to look there, and the weather is great and the big thunderstorms come rumbling off in the summer. And you know it's sort of a glorious place.

We're still not quite sure why the Rockies are there, but they're probably, sort of, a rumble from the subduction zone coming under the west. This is-- on the edge of Florissant is South Park. If anyone happens to have seen the cartoon show, this is a picture of the real South Park as opposed to the one on the cartoon show.

And it's a really pretty place. If you ever get a chance to go, there'll coyotes down in there and antelope coursing around, lots of little wildflowers. The parks are the downfold, and so as the West was, sort of, rumpled up you've got some upfolds, which are the mountains, and the downfolds, which are the parks. And there's South Park, and there's some other parks-- Estes park and so forth - on as you go up.

And so on the edge of that is the Florissant Fossil Beds, and the Florissant Fossil Beds was an old lake that had little layers of mud put down and pressed in those layers of mud you get the most beautiful fossils, just tremendous. Ages and ages ago, before it was a federal preserve, you used to be able to collect there. And I actually did do a little collecting there when it was legal and moral and upright and proper, and now you cannot. It's preserved for the public.

But they're just beautiful fossils, and they are slightly different from things that you'd find alive today. And of course, that's the interesting thing that one sees is that as you look at the fossils from different ages, you find slightly different appearance in those fossils. OK, now we also are going to briefly visit another park. This ones a little farther back in time. This is an opportunity we had with our CAUSE class to go to the Petrified Forest.

We had the paleontologist at the Petrified Forest taking us around, and so you will meet William Parker here in just a minute and Randall Irmis. And, oh, man, we had a great time there. As you can see, that's a petrified tree behind our CAUSE class sitting there. And this is another one. This is araucarioxylon arizonicum, which is what a lot of the trees are in the Petrified Forest.

The Petrified Forest looks to be almost entirely a big flood deposit. A giant flood washed in the trees. The trees have had the bark knocked off of them, so they're bouncing around in the flood and what have you. And it's in a place there's a lot of volcanic ash, and they're silica coming out of the volcanic ash. And as you know, there's dissolved minerals in water all the time. And if you get to a chemistry change, things happen.

If you have dissolved minerals in the water or in your bathroom and you come to a chemistry change as the water comes out, you may get hard water deposits depending on whether you pay for the water softener. And you get deposits, and then you need the big wrench to get the faucet open when you need to replace the washer. Well, the same thing does happen.

The chemistry inside a rotting log is really different than the chemistry outside, and in particular, you get a PH such that it will pull silica out under favorable circumstances. So you bury the log. You bury it fast enough that the termites don't get it, and you get enough volcanic ash around that puts enough silica in and then sometimes you get stone OK.

And this one-- this is the alpha stump, and Will Parker took us out to see this. It's out in the black desert section way up the Black Forest section way up to the north, and this is one that's still rooted in place. It's got its roots sticking out from it, and so here is the bottom of the stump. And we'll try to get our pointer options and bring our pen back, and then we'll try to go back to see the alpha stump.

So here's the roots, and we still didn't get the right color of pen. So let's see if we can get the pen color, and we'll see if we can turn it red so that you can see it. Because this really deserves being seen. And so there's a root coming off of the stump and another one started out there. And this is, sort of, a river gravel with a little soil developed on the top. And this thing grew right there and it's still sitting there in place.

And you can see the root coming out and the great paleontologist Will Parker right there, and our crew filming him to see what they can learn from him. This is probably the world's oldest fossil bees nest. You can see in the petrified wood over the fingers here where there are burrows that had been cut into the wood, and there's a close up of them over here in the upper left that you can see.

And so here is something that was burrowing in the wood before it was turned to stone. It's so cool. It was just truly amazing and just this wonderful paleontologist. And so this is Will Parker on the right and it's Randall Iris on the left. And they're out actually excavating a plate that was armored protection for a giant reptile, an archosaur that live back in the Triassic here in Petrified Forest.

And you can see right next to Randy's finger there. You can see where his big plate-- this reptile was. And we're out walking around. We're picking up teeth. Here is Randy showing Irene Meglis a tooth right here. That tooth you could still cut yourself on. The point was still sharp. There's still little serrations on the side for tearing into things. Just wonderful place.

And these are things that look a little bit different than what you find on the world today. Big amoured reptiles look a lot different than what you'd find in the world today. And so there are clearly changes in what's lived over time. And so we are now going to pause for a minute on looking at pretty pictures, and we'll switch over and we'll write about some things.

The subject of evolution I'd say is a hot button. Scientifically it's well-founded. There's really no argument. There's lots of arguments about the details of rate, the details of processes. Can you evolve while you're interacting with somebody else? Let's walk briefly through the basic ideas of evolution, what it is, and then maybe we'll come back and chat a little bit about some of the hot button issues.

OK, observation one, if you watched really carefully in some of the beach pictures a few days ago, you actually saw my daughters. And thankfully my daughters do not look identical to me. They're not the same height. They have very much more melodious voices. They're better looking than I am. And so the first thing that goes into evolution is that kids are not identical to their parents.

And this is true whether you're looking at Guinea pigs or whether you're looking at my wonderful daughters and my wife's wonderful daughters, that kids really are experiments. There's a little bit of tweaking goes on so that the offspring are not identical to the parents. You really can look at your kids as being experiments. I wouldn't say that really loudly, but they'll probably figure it out anyway that nature has experimented a little bit with them. They may be a little faster or a little slower.

They're, sort of, like us. I'm actually 5'7, 5'6 and 1/2. I'm the tallest Alley that's been for a long time. And my kids actually are not terribly tall people either. We didn't have any seven footers. They're not going to be really great basketball stars. And so they're similar to us, but they're not identical to us. They really are experiences.

OK, the next piece of evolution-- but this is, sort of, common sense. People mostly know this-- the next thing that goes into evolution is that these differences between kids, the differences between one and another, the difference between the parents and the kids affect success. OK, so these differences affect success. And we're going to have to define what success is. You have to be careful with things like this, OK. Because in the evolutionary world, in the biological world, success has a particular meaning that may not apply in college, for example, which is the ability to stay alive, to have kids who have kids.

If you don't stay alive, you don't have kids. If you don't have kids who have kids, eventually in your line dies out. If I weren't having kids, we wouldn't have Alley's down the road somewhere. So it's the ability to stay alive to have kids who have kids, right. If you cross a horse with a donkey and you get a mule, it can stay alive but it can't have kids, because it's sterile. So you've got to be able to have kids who themselves can have kids and so on down the line, right, and on down the line.

OK, so for us, I don't know how relevant this is. We can-- if I had a disease, like that doctors might keep me alive. We humans have, sort of, changed the natural balance. But even there, it is conceivable that by this definition that the differences between say me and somebody else would affect my ability to stay alive to have kids who have kids. If I were seven feet tall and if I were really, really good at throwing a basketball into a hoop, it is just barely within the realm of possibility that I would have more opportunities to reproduce the I do as a 5'7 balding professor. It's possible. OK.

So even with humans, this is indeed true. You can imagine out in the real world where people-- where things get eaten, that this would make a big difference. So if you are a squirrel and you're a really, really slow squrrel, the bobcat gets you and that's the end of things. On the other hand, if you're a really, really big squirrel, you might be faster. But if you're too big, the mountain lion sees you and the mountain lion gets you and that's the end of things. So how much you stick out, how easy you are to be eaten is going to affect your ability to survive.

If you're a squirrel and you don't have your tail and you jump and you can't balance while you're jumping and you fall out of the tree and the bobcat eats you, it's the same sort of problem. And so it's clear that in the natural world that differences do make a difference. It doesn't have to be huge differences.

There's this hideously wonderful old joke about the two guys that are out backpacking, and the grizzly bear shows up. And somehow they know this grizzly bear wants to eat them. And so the one guy takes off his backpack, and he sits down and he starts taking off his hiking boots and he puts on his running shoes. And the other guy says, well, why are you putting your running shoes on. You don't-- you can't outrun that bear anyway. And the guy with the running shoes says, no, but I can outrun you. And so it's the differences may just be enough to succeed relative to the others around you. So even small differences might make enough to matter, OK.

The third thing-- and this is the big piece-- is that which makes you biologically unique tends to be passed on to your kids, more or less, OK. So if I were seven feet tall and really good at throwing the ball into the hoop, the odds are pretty good that my kids would also be tall and they'd also be good at throwing the ball into the hoop. So we add here that what makes you, what makes any creature, what makes you biologically unique tends to be passed on to your kids.

This is a statement if you want easy words. This says, hey, your kids sort of, look like you. But again, there's this little bit of experimentation. They may get a little more of it. They may get a little less. They may be a little taller. They may be a little shorter. They may be a little hairier or a little balder or something like that in greater or lesser amount.

Now these statements running over time, deep time give you evolution, and that's all it is. You got to watch for a while. Because the differences are small, you start looking at a hundred generations to even see the tiniest little tweaking, a 1,000 generations, 10,000 generations before you start to notice things. So we humans, it takes us 20 years to breed, and it, sort of, takes a long time to see any change. A thousand generations at 20 years per generations is 20,000 years to see anything happen basically.

If it's the cold bug that I've been trying to get rid of, they're a little faster in breeding and they do it in 20 minutes. And so next year there's going to be a new bug and you're immune to this one. But next year, they'll be a new one get you, because they change so very fast. And so these sorts of changes you've got to, sort of, have theology sitting in there, OK.

Now you'll recall, I hope, that back a little bit we've looked at the law of faunal succession. And we said this is not a law that was passed by Congress. This is a generalization. And what it says is that as you put the rocks in order, you put the fossils in order. And so we have the law of faunal succession, which is sort of things changed over time, living things changed over time.

And this is an observation. It was an observation that was not made by Darwin. It was not made by evolutionists. It was not made by the anti-religionists who were trying to overthrow a belief in some higher power. It was made by a canal engineer who wanted to do a better job of digging ditches. It was something that was practical. He clearly suggests the possibility of evolution. So once people had seen these changes, they started saying, OK, well maybe this is going on.

It does suggest evolution. It does not prove evolution in any way. One can simply look at the cars that come out of the Detroit. You have Ford Mustangs, right. When I was little my best friend's mother had this 1964 and a half Ford Mustang convertible, a white one with a black top. And it was cool. And those 65s and 66 and 67s were really nice, and then they made these giant bloated hideous messes of Ford Mustangs for a while. And then eventually they made them cute again.

If you set the Ford Mustangs up in line, you can see a progression. You can see a change in Ford Mustangs over time. But I hope it's evident that the 1964 and a half Ford Mustang did not give birth to 1966. It's clear that it's possible that you can have lots of special creations. That you can see, make a mustang, OK, make a different one, OK, make a dinosaur, OK, make a mammal. You can see this.

And early geologists argued about this. Is it possible that we're seeing lots of different special creations that make this happen? What happened is that eventually evolution won, OK, and why evolution won mostly is that a couple things happen. One is-- so evolution won, it made the right predictions. Evolution says we should see transitions. And then they said, OK, now we're going to have to look really carefully, because there's this little problem that most living things don't get fossilized.

Here in Pennsylvania, we have-- we have a million deer in the state, and the half of them are bucks and each of them has two antlers. So every year a million antlers fall off of deer. And even a few thousand years since the prime of the Native Americans with a million antlers a year, you know that when you go walking in the woods you just stab yourself all the time on these piles of antlers that the deer have left, you don't. And of course, you don't.

And the reason is as fast as antlers fall off, somebody eats them. The minerals in those antlers are useful. The deer eat them. They're not there. There is no record of fossils of deer being made out there in the hills of Pennsylvania right now. And so you have to, sort of, go look in places where fossils are being made.

A lot of this work has been done on shellfish in shallow water, because a shell is really a rock and it's already there. And so you can go and look very carefully at the fossils, and you can see the changes over time. And there's just an immense amount of evidence for this happening. What one sees is sometimes you'll see-- it's a little thing, and then a million years later it's a little bigger and a little bigger and a little bigger. Sometimes you see splits. You have one type, and then pretty soon you have two similar types. You see very, very fine transitions between given types.

You can go up across northern Ohio and Pennsylvania and New York and see very, very fine changes in trilobite eyes, for example, from the number of columns of elements in the compound eye of a trilobite and watch them change over time. And so what you find is that you-- it predicted things that were found. And among those is transitional fossils. It is things that you can see that change over time from one type to another.

Now, not every transition is known. Not every fossil is known. You will never, ever, ever find the remains of everything that lived on the planet, because we recycle. The planet recycles. It's really, really good at recycling. And so because of that, you're going to have gaps in the record.

What you find is that the transitional fossils are there about as often as they ought to be. As you find more fossils, you fill it in a more complete record. And so you find them-- they're found as often as they should be.

The ones that you most care about are probably pretty scarce. If you want to know something about the ancestors of cats, cats are not fossilized really well. If you want to know the ancestors of clams, clams are fossilized really well. And so the record is much better for clams than it is for cats. That's life, OK.

The other thing is that evolution says, look, Darwin's saying there must be some way that I biologically tell my kids what they're going to be. There must be a mechanism for this to work out there. And so the early work on evolution didn't know genetics, but it said it must be there. It will be found. If this picture of the world is right, eventually you guys are going to figure out what came to be called genetics. And so it predicted the mechanism, and now we know that the mechanism has been found.

And so the mechanism's predicted and found, observed. It's there. And right now if you were to ask anyone working on this, biologically evolution is completely unavoidable. We haven't any clue how you could make it not happen, because your kids are experiments and that does affect how well they do, OK.

Now it's nailed. Scientifically there's no debate about this. The debates are about how fast it goes and so on. Evolution is a practical thing in many ways. So evolution is used for practical things as well as for other things. If you go and search on the web in the web of science, the ISI web of science, and you look for antibiotic resistance and evolution, you will find hundreds of scientific studies on that particular topic. And if you go look at them, there's a lot of people out there that are trying to figure out how to keep us alive.

It turns out that -- we get bugs and they live in us and they kill us sometimes. And so we have invented antibiotics that will keep the bugs down. And as soon as you have billions of bugs in you and you subject them to something that kills them, if there's one of them figures out the tweak that allows them to get around that problem, suddenly that one reproduces like crazy and you have an antibiotic resistant bug. And what we've seen is that over the years, every tool that we've invented to protect ourselves has been defeated by the bugs.

And so this is a red queen's race. We're going as fast as we can. The bugs are going as fast as they can, and we're trying very, very hard to stay ahead. And people really are using, sort of, the theories, the models of evolution to ask how can we win this? If we take some of the antibiotics off of the market for a while, there must be some cost to that bug to beat that antibiotic. Maybe they'll lose that ability, because now they're paying for a protection that they don't need. And then you bring it back in and zap them and maybe you can win that way.

And so there's lots of people that are using evolution to try to keep us alive. And I say you don't have to believe in evolution, but you better know somebody who does because it really is a very useful thing. Now again, there's nothing anti-religion in evolution. And I think it's very, very important to get that, that evolution is not anti-religion. There are a number of things that we put in the text and in the enrichment of the text, it you really care about this particular topic. Jimmy Carter, ex-President of the United States, habitat for humanity builder, purveyor of democracy around the world, and probably the world's most famous Sunday school teacher has said, look, we don't-- evolution and religion can get along. There's no problem here.

The pope has said that. The pope said, fine. He said now you listen to me. He said there are some things that I know about humanity that Darwin didn't, and I'm not going to go back on that. There are things that I know as the pope that Darwin didn't, but he said it's fine. Darwin can do his thing, and we'll do our thing. And we'll get along. There's no problem here.

In fact, the great majority of religious groups in the United States say, fine. We can coexist with evolution. There's no big deal here. There are groups that say no. I know the literal truth, and it doesn't happen to agree either with Darwin or with the age of the earth. And so they're just wrong, and we're going to fight it. But there's certainly nothing that has to be anti-religious in evolution.

I mean, in the interest of disclosure-- I'm not proselytizing. I'm not trying to run you in. We actually are a religious family. I'm a religious person. I belong to the United Methodist Church, and the United Methodist Church is among those churches that say it's OK. We have some beliefs. We think there is something bigger than us. But we also can have Darwin. There's no problem with this.

Darwin is useful. Darwin helps keep us alive. Darwin is supported by an interlocking web of observations. There's not one piece that you can knock out and it falls down. There's an immense amount of evidence for this. And so like all good science, there is an interlocking web of observations for this.

And we'll just go ahead and write that. This is important. Remember, ultimately we want you to, sort of, get what scientists are doing. And it is, there's no single observation that would knock this down at this point, because there are so many tests have been done, hundreds of thousands and tens of thousands of let's see what predicts better. And this picture of deep time and the living things that have kids that are slightly different from them and that affects their survival is a big deal. And so it does.

Now let's very briefly support-- let's very briefly chat about two more things, and then we'll move on to extinction. And I apologize if you're totally with me and you say what's he beating on this for? Well, I apologize. You can fast forward through this.

But if you read the letters to the editor, if you have a discussion with people that don't like evolution, very often it quickly boils down into issues of morality, issues of what should be rather than issues of what is. And you'll hear if you believe in evolution, then you're Hitler. And if you have read enough letters to the editor, that does come up sometimes.

I actually have really, really lousy vision. Infinite focus for me is about right here. And when I go to eye doctor, I cannot see the big E without my glasses. And it is very likely that I have a genetic predisposition that I'm one of these people that if you read a lot when you're young, your eyes, sort of, get shaped for that.

So it's not that you're born with bad eyes. It's that your, sort of, plastic to this. And my daughters have this too, and they all have bad vision. Now that is something that maybe having me in the gene pool is a very bad thing. That's evolution, that if I'm left alive to breed I have kids who also have this issue, and they will be left alive to breed. And so we're not getting rid of me in the gene pool.

Now does that tell you what you have to do about this? And the answer is obviously not. You could have sterilized me when I was a kid. As soon as I got my first glasses, you cut off various pieces of my anatomy and then I wouldn't have kids and we take care of this, OK. That might be Hitler.

You also could have said that poor schmoe is real nerdy looking with his glasses. I used to have the big plastic rims. He's really nerdy looking with the glasses. He's disabled. Maybe we should give him dating lessons. And so we'll help him to get along, because we're trying to overcome the disability that nature has given him. Or you could have a technological fix. You say, OK, he gets glasses. He works no problem. Don't worry about him.

My kids have contacts. They are a little more stylish than I am. But evolution doesn't tell you what you have to do about this. It is. It's not what ought to be or what will be or how we will do it. It just is. It just is. And so it's something that we can use that knowledge and move forward. Evolution by itself is not anti-religious. It's not anti-society. It doesn't lead to bad things. We humans decide what we're going to do and it goes from there.

And there's one other point is that you may possibly know that over the last couple of decades, there's been an immense amount of argument about intelligent design. The courts have very clearly said, you can't go and teach one religion in the schools, because there's lots of different religions. And a lot of religions believe this and a lot of religions don't. And so there's been this real push to get intelligent design into the schools.

And just a very few years ago, this was especially going on in Pennsylvania. It was going on in one particular school district, which was Dover, sort of, a test case. And intelligent designer as it's been promoted recently is a very interesting thing. It allows an old earth. OK, so this is not actually young earth creation. It allows an old earth. It allows evolution.

But it says in the course of evolution on the old earth, occasionally some unspecified intelligence tweaked something. So there were unspecified intelligence-- unspecified intelligence tweaks. OK, and what do they say is the evidence for this. They say there are certain things in us and living things that are too complicated to have come about by evolution. Evolution works in small steps and they say, oh, there had to be a big step. So some unspecified intelligence came in and tweaked something.

Now they use to talk about the eye. The eye is a remarkably complicated thing, and they'd say, well, half an eye is no good to any one. And therefore the eye had to arrive, boom, in one thing, therefore there has to be an intelligent designer, therefore, what follows. They don't talk about the eye very much anymore, and the reason is that part of an eye is perfectly useful. And if you don't believe that, imagine in your mind for a moment, imagine that you've had some terrible disease and it's taken out a lot of your vision and you can't read anymore. You can't focus greatly, but you can still, sort of, see shape and shadow or you can see light and dark.

And somebody comes-- a doctor comes in and says, well, I have a medicine that will allow you to keep seeing a little bit. Will you pay $100 for the medicine. And of course, if part of an eye is worthless, you'd say, no, I won't pay $100 for the medicine. I'll just go blind. And in fact, everyone will say, no, I want to keep what vision I have. Some vision is useful.

There are critters in the world that have no eyes. There are critters in the world that have little eye spots. There are critters in the world that have just vague vision. There are critters in the world that have good vision. It's very clear that evolution can work and that small steps will matter.

And so they don't talk much about the eye anymore. Now when they talk about is the flagellum, that little whip on the back of a little microbe that helps it move along, or they talking about blood clotting. And the courts have looked at this, and they've said, OK, the scientists are not having a lot of troubles explaining the flagellum. And so somebody from an intelligent design institute who says they can't explain the flagellum so you have to teach about intelligence in the schools, that's really religion.

I wrote a piece that is on the website that showed up in some newspapers in Pennsylvania, which was on what we should teach in science class. And I said a lot of science is not truth. I have my own beliefs. Other people have their own beliefs, but in science class we should teach science. And we should be very careful to teach science in science class. And after that, I had this wonderful discussion with a whole bunch of people who e-mailed, who wrote, who stopped me on the street. People cared very deeply about this.

And a couple of people said, well, you're damned to hell. You're a bad person. They're going to get you for this. But most of them were very polite, very interested, knowledgeable in many ways. And so we had a discussion. In that discussion, every single one of the people who told me what they believed about the intelligent designer believed that they knew who the intelligent designer was and they believed that the intelligent designer happened to be the deity that was worshipped in their church.

And that's what the judge found at Dover, which is intelligent design is not really about flying spaghetti monsters. It's not really about UFOs. It's really about religion trying to come in as science. I also have some religious leaders who desperately did not want to see intelligent design taught in the schools.

They said imagine that you believe that your religious. Imagine for a moment that you're a religious person. Do you want to promote your religion by having a biology teacher tell a tenth grade class an intelligence helped design you, and we know this because biologists are having troubles explaining the flagellum. OK, now what happens when the biologists explain the flagellum. Is that a-- is that a good rock to build a religion on, the difficulty of biologists explaining a flagellum?

And so in fact, these religious leaders said desperately don't do this. This is a terrible thing for religion to try to teach it from flagella in biology class. And so this is now by the courts, this has been said to be religion. And so the Dover court said this is religion. It doesn't belong in science class. So put it somewhere else, OK.

So that's-- and if you want to talk about this some more, it is a very interesting topic. A lot of people care very deeply about this topic. There is a good bit more Q and A and, sort of, arguments and arguments back and forth on the website material you can chat about.

So, let us now get off of that subject, which we stayed on probably a little too long, and let's go see what-- if you have evolution, what comes after that. And what comes after that is often extinction. So let's now go, this is a picture of Dinosaur sitting up in Colorado and Utah, and the rocks are, sort of, old river deposits. And they're tipped up on the edge, and in Dinosaur, there's dinosaur bones.

And this is just a really tremendous place. They took this one big-- it's an old sandbar that's tipped up on edge. And sitting in that sandbar, there's an immense number of really big dinosaur bones. And this is serious scale. Oh, I thought I had a picture with the ranger in it. At any rate, this bone is, sort of, as big as you are. So there's all these dinosaur bones sitting up there.

And what we're going to argue for you is that the dinosaurs lived for a long time. They were doing great. They were happy. They were healthy. They were terrific. And then they got done in by a giant meteorite. This is a little tiny meteor crater. This is the Barringer Impact Crater in Arizona.

You'll see the visitors center for-- this is actually not a national park, but the visitor center is over here, and the road is coming in here. And then this crater is, sort of, most of a mile across. This is a little crater. This is not a big crater. And we think it was a really big one that got the dinosaurs. This is a picture over here on your far left. Between the pink arrows, there's a picture of the crater.

It is, sort of, off the Yucatan Peninsula, and this thing is 110 miles across. So-- and that circular structure there shows where the meteorite hit and the hole it made. It would have been a pretty big one. There's a number of pieces of evidence that one finds where meteorites hit, you get broken up pieces of stuff. And this is not from-- not from this crater. It's from a different one. But there's broken up pieces in both of them.

And you get minerals that look really funky. They get these funny lines running through them if you hit them really, really hard. And the layer in when the dinosaurs were killed has that. This is the layer. There are dinosaur fossils below this, and there are no dinosaur fossils above this. And in this layer, you find those funky shock quartz, and you find things that look like this. You find little spheres of melted rock that were splashed out of the thing.

And it's just this wonderful-- something happened. The world changed right there. This is one of the most amazing things that you'll see. This is work that was done by many people. My friend, Brian Huber, was involved in this at the Smithsonian Institution. He is a wonderful, knowledgeable, tremendous person.

And what we have over here-- they went off of the nose of South Carolina, which is a long way from the Yucatan, OK. And they pulled up-- they drove a pipe down into the mid and they pulled up the mud. And they pulled up some hundreds of feet of white mid. And at the bottom down here, here is some of this white mud. And they'd get hundreds of feet of this stuff.

If you go and look in that white mid, you find these fossils that are over on this side. And there's big ones and there's little tiny ones and there are all different kinds of fossils in here. You see a great diversity, some really cute looking things like this. You see this great diversity of different things, and they were there for a long, long, long, long time.

Now this is out in the ocean. You're not finding dinosaur fossils, but you are finding all of these different kinds of things. And then there's a layer, and this layer is just a few inches thick. And this layer is full of pieces of meteorite, and it's full of pieces of things that were splashed by the meteorite. Above that layer, it goes back to being white mud.

But when you look in the white mud, you find just one, two kinds of things. It's all the same. The big ones are gone. The diverse ones are gone. Lots and lots of stuff all over the world, you've got the diversity of a great sort then a splash from a meteorite and then almost nothing left. And this is remarkable, OK. Just a truly amazing, amazing thing. And so we're going to try to draw some pictures for that for you very quickly. And we'll see what we can do with that.

So pop forward here just a little bit, and what we see, you will remember that we went back and we put things in order. A long time ago, we put rocks in order and we had a Cenozoic, which had the age of mammals. And below the Cenozoic with the mammals, we had the Mesozoic with the dinosaurs. And below the dinosaurs we had the Paleozoic with shellfish. And below that, we had the Precambrian. And if you go look in the text-- and this was algae-- and you go look in the text, you, sort of, have a vague idea of how-- when these different things happened.

The 4.6 billion years ago to start the world. I actually can't remember what we wrote in the text. It's about 570 million years ago to start the shellfish. And what was this? 225, I think, million years ago to start the dinosaurs. And this is 65 million to start the-- to start the mammals.

If you have looked at bio-diversity on the planet, you'd find that there was, sort of, a spreading. There were more types showing up. There were lots of different things popping in. And then there'd be a mass extinction. So you'd get few types, and then you'd, sort of, get more types showing up. And these are all different kinds of things that are alive. And you're getting more and more coming in and then, boom, something wiped out most of the living things on the planet in a very short period of time.

And a few of them survived, and then more things would show up. And you'd get this great diversity popping in. And evolution is creating new things. And wow, it's exciting, and there's dinosaurs, and there's little tiny mammals running around. And then, boom, most of them get wiped out. And you saw the line in the rocks where those different kinds get wiped out. And then just a few things come through, and then we get evolution that comes up and gives the diversity that we have.

This boom down here, that wiped out the shellfish, we're still arguing about that. And there's people at Penn State, colleagues that I have that work really hard on this and they're making great progress. This boom up here was a meteorite, and we have high confidence that it was a meteorite. And some of the evidence for that I showed you pictures of, and so why do we think it was a meteorite?

Well, what you find is this layer all the way around the Earth. And in this layer, it is full of things that come in meteorites but that are rare on the planet. Iridium is something that's very common in meteorites. It's very rare on the earth. So it is full of iridium, which is a marker. It is full of-- which is common in meteorites, rare on the earth.

It is full of these little melted blobs of glass, melted glass blobs that you get by melting them. And so you've got to make it warm to do that. The meteorite makes energy, and so it can do that. It's full of that shocked quartz, things that have been hit so hard that it changed the mineral structure. And so it is full of shocked quartz, and you've got a shock quartz to give it a shock. And the shock in this time is hitting it really hard, so this is hit hard stuff.

And it is-- when you get near the Yucatan, there's a giant wave deposit. And so there's a giant waves deposit. And then we have the meteorite, and they're all the same age. And so we have the crater, and it's as close as we can tell, it's the same age. So that works.

Now the meteorite didn't fall on the dinosaurs head. It didn't go POP and kill them all off. It's one meteorite. How do you kill dinosaurs with a giant meteorite? And what we think happened is a whole bunch of things, sort of, fire and ice. Some say the world will end in fire, some say in ice. From Robert Frost, we think there was a, sort of, fire and ice thing. There's this layer all around the world.

Now, if you've ever seen a meteorite coming in, a shooting star coming in, or a spacecraft coming in, it gets hot. Friction with the air makes it hot. And so things that fall down fast get hot, all right. So fast fall goes to hot.

Now what happens if you blast an immense amount of stuff that surrounds the Earth and it all falls in at once? It gets hot. And if you can just imagine the sky suddenly being nothing but meteorites-- little ones coming back to make that layer-- the whole sky is a toaster boiler oven. Everything burns, OK.

So as the stuff you blast rocks out, they fall back. They heat from friction, and they burn. OK, the layer is full of soot in many places, which is the black stuff that comes off of a fire. There was a gimongous conflagration it appears. And so we see this soot from the fire in the layer.

All right, but what happens next is you know if you blast stuff up, the big pieces fall down fast and the little pieces fall down really slow. And while they're up there falling really slow, they're blocking the sun. And in addition, the meteorites hit some rocks that have sulfur in them. And the sulfur makes sulfuric acid. And so the meteorite hit sulfur rocks, and that gives rise to sulfuric acid, which is not nice if it rains on your head.

And it also gives rise to - while it's up there making the sulfuric acid, it's blocking the sun. And that gives you cold, because you block the sun and it gives you really serious acid rain. And so this is nasty, and this is cold. And if you get burned and then you get acid rained and then you get frozen out, it's sort of hard to get through. And so the observation is most of the living things on the planet died in one moment.

Now it's 65 million years since this happened, so this doesn't happen very often. You don't have huge worries. You're in much, much, much, much, much more danger of being run over by a car than you are being hit by a meteorite. But it did happen, and it did change the history of the planet. And so we see this really, sort of, amazing story, and we see the dinosaurs gotten out of the way by a space rock which actually made room for us.

Credit: Dr. Richard Alley

Want another look?

Check out the Unit 11 Presentation used in the online lecture.