How should evolution be taught differently?

[Jose]

Of course, we need to do a better job of teaching the science, and we need to teach evolution differently so that it makes sense...but that's another issue.

That's an interesting statement, "we need to teach evolution differently so that it makes sense". Are you implying that current methods of teaching evolution does not make sense? If so, what changes should occur to have it make sense?

I have claimed that we should teach evolution differently. I have my own opinions about current methods, and about alternative methods (which I use), but first let's think about it more fully:

• How many of us think that our high school classes gave us a good understanding of evolution? Maybe if we all think we understand it perfectly, and thus accept it as valid, then we don't need this thread. It doesn't seem that we all feel this way, however...
• What are some specific problems with current teaching of evolution? Let's be specific here, rather than just say "it's a fairy tale" or "it's a religion" or "it's not how God did it."
• What parts of evolutionary theory do you feel are unsupported, vague, or simply "asserted to be so"?
• What do you think needs to be done to fix this? Creationists may say "throw it out," but this isn't a likely option. Nor is it useful to say "teach creationism alongside," because that doesn't improve the teaching of evolution. We need recommendations for how to solve the problems revealed by the answers to the first questions.

[MagusYanam]

Again, there seems to be a misuse of the word 'theory'. The label of 'theory' simply means that the proposition - in this case, evolution - seems to be the best explanation for what 'facts' we have. And, Titan, you are right - it should be taught as such. But the popular attitude that 'it's just a theory; it isn't true' is a wrong way to look at it. It's true that there are problems with the theory, and the evidence we have would suggest other factors, but in order to make sense of them we must work from the standing theory.

Remember (evolutionists as well as creationists), the Darwinian model grew out of the previous Lamarckian model, and the Lamarckian and previous models grew out of the six-day creation model. It may be that the Darwinian model is insufficient, but until it is proven so it is the model from which our sciences and our education must work.

[juliod]

I feel that they treat it too much like a fact and if someone disagrees with a point they are considered ignorant. Remember, this happened in the past and we don't have a time machine.

Evolution happens today. It is demonstrable in both the laboratory and the wild. Evolution is both a fact and a theory. (I.e. The theory is an explanatory framework for the fact.)

How were cells able to become specialized, what triggered it?

Ad Hoc explanation:

There may not have been any "trigger". Specialization probably developed during the initial abiogenesis. A clump of protocells probably contained cells with different biochemistries. Some cells produced certain compounds, other cells produced different ones. By diffusion, all the cells recieved all the compounds. A great benefit for all the cells.

Whole organisms (such as autonomous bacteria) may have developed later.

We can see a possible remnant of these clumping cells. I'm sure you've learned about the sybiosis theory of mitochondria. Mitochondria do seem to be a bacterial-type cell that has been engulfed by another cell. This is an benefit because the biochemistry of the mito is highly specialized. But this event would have had to happen very early in evolution since mitos are ubiquitous in the animal and protist kingdoms (I confess not knowing about plants).

Remind kids that it is a THEORY, not a fact.

Repeat until you get it: "A theory is an explanatory framework. It is not an intermediate between 'doubtful' and 'certain'."

DanZ

[Titan]

Evolution happens today. It is demonstrable in both the laboratory and the wild. Evolution is both a fact and a theory. (I.e. The theory is an explanatory framework for the fact.)

You are correct, although a creationist friend of mine would ask why we don't see any new organs being formed. The theory is about whether or not evolution was the source of all life.

A clump of protocells probably contained cells with different biochemistries. Some cells produced certain compounds, other cells produced different ones. By diffusion, all the cells recieved all the compounds. A great benefit for all the cells.

Do you have examples of such organisms that would first bond then work together. I mean we don't observe such things in the labortory.

Repeat until you get it: "A theory is an explanatory framework. It is not an intermediate between 'doubtful' and 'certain'."

This is the definition that I was using: A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.

[juliod]

although a creationist friend of mine would ask why we don't see any new organs being formed.

Ah, but we do. Think for yourself what an organ evolving into another organ would look like. It might go through a period where it wasn't doing anything in particular. It lost it's old function and hadn't yet achieved a new one. Hint: think apendectically.

Do you have examples of such organisms that would first bond then work together. I mean we don't observe such things in the labortory.

Again, we do. Think soap. Detergents and lipids are members of the class of chemicals called surfactants. Basically any compound that has both polar (or charged) and nonpolar region can be a surfactant. In water, surfactants tend to form foam and bubbles. You'll note that foams and bubbles tend to stick together. If they have water on both the inside and outside we call them vesicles. A biological cell is basically a vesicle. Chemically, the significance is that the inside of the vesicle is protected (somewhat) from the outside environment.

If you had a case where a group of vesicles contained an environment favorable for the reactions that make the surfactant then you would have a crude case of chemical reproduction. In other words, where the visicles were there would be an increase in the amount of surfactant, which would make more vesicles.

Now, most chemical syntheses involve more than one reaction. So if you have a group of vesicles, some of which favored step one, and some which favored step two, etc, then you would essentially have a self-replicating, multicellular proto-organism.

This is the definition that I was using: A set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena.

Right. That's a good short definition. Notice that a "theory" is not an alternative to a "fact". A poem or novel may be an alternative to a theory (i.e. they are all sets of statements).

DanZ

[Jose]

How many of us think that our high school classes gave us a good understanding of evolution?

Well, I'm taking and advanced placement class so I get a pretty good understanding. Our book has about 10 chapters on it.

Ah, but are they good chapters? They usually start with "evidence for evolution" and then go to vague examples of "directional selection" and "disruptive selection" without ever telling us how changes in DNA sequence can actually cause phenotypic changes that selection can act upon. Most people come away thinking it's pretty vague.

What are some specific problems with current teaching of evolution?

I feel that they treat it too much like a fact and if someone disagrees with a point they are considered ignorant. Remember, this happened in the past and we don't have a time machine.

A good description of the typical classroom session, all right. I think it stems from the world-view that most students have that every question has only one right answer (especially in science). We've got to break that bad habit. Most questions have many potential answers (especially in science), and we have to sort among them for the one that fits the data best.

What parts of evolutionary theory do you feel are unsupported, vague, or simply "asserted to be so"?

Certain formations are never addressed.

Formations? As in limbs and eyes and stuff? Or as in rock formations? I'd guess the former--in which case I'd suggest that the answer lies in the gradual disappearance of embryology from most biology classes. We need to put it back in. With the advent of molecular genetic techniques, we've figured out a lot, and can describe these things much more clearly. This makes evolutionary change in these structures much easier to understand.

I have a quick question, my class didn't give a good response to this: How were cells able to become specialized, what triggered it? Because from what I heard the theory is that they were bumping into each other. I thought that there had to be a better explanation.

The way that many biologists look at it is to think about different types of things that exist now. This is incomplete information, of course, because everything that exists now is highly evolved from the distant ancestors. Still, there are enough examples of so-called living fossils that we can infer that many environments have been fairly stable. So, here goes:

Many bacteria and fungi form biofilms. These gunk up stuff like the pipes that circulate the water in hot tubs. They all just kinda stick to surfaces, and end up sticking to each other. This provides a situation in which some minimal level of cell-cell communication is advantageous.

Some fungi and algae are unicellular, and some are colonial (eg volvox). Each cell is a whole organism, but the cells cooperate. A little more cell-cell communication is advantageous. So is a little bit of cellular differentiation, to make two cell types--body cells and reproductive cells.

Sponges are also colonial, but have more cell types--something like 4-7. Here's a bit more communication, and a bit more cell differentiation.

Then we have animals and plants, which have lots of cell-cell communication and lots of cell types. But, the basic pattern was set up way back in the biofilm, when cells first stuck together and started to communicate. You recognize, of course, that I'm thinking about ancient, simple organisms using current, complex ones as the model, so there is bound to be some inaccuracy in this. Still, the overall logic seems sensible enough, and fits what we see in the fossil record.

[Dilettante]

Hmm... the creation/evolution teaching controversy seems to be an American phenomenon. I don't know much about the US educational system (I might, however, apply for a temporary teaching exchange there one of these years). But if I may put in my 2 cents, I think what's wrong with the teaching of evolution is probably the same thing that's wrong with high-school/secondary level teaching elsewhere: students are not taught to think. I agree with Jose, multiple choice tests are horrible because they promote impulsive answers rather than reflection.
Also, at least in my experience teaching English, it's hard to get students interested these days, when the outside world is so full of dazzling stimuli.

[juliod]

But if I may put in my 2 cents, I think what's wrong with the teaching of evolution is probably the same thing that's wrong with high-school/secondary level teaching elsewhere: students are not taught to think.

I don't think it is possible to tech students to think. IMHO in school you get out of it what you put into it. I think that is true everywhere, but hidden by the differing cultural assumptions.

Science classes enhance this effect. It requires committment by the student in order to excel in science. So most students only slide by, or do the class by rote. OTOH, if you have interest and aptitude there is no limit to your advancement.

I am a radical heretic as far as US public schools are concerned. I don't think there is anything wrong with them. I find it interesting that over the period where nearly everyone has been wailing and gnashing teeth about how awful our schools are that the US achieved near universal dominance in all areas of science and engineering.

As far as evolution is concerned, we cannot expect high school students to digest the full implications of the theory. In science every field, sub-field, and sub-sub-field fades off into the areas where we currently don't have the answers. It's there where the details, and the difficult questions, lie. In schools, in textbooks, and in the guidance for teachers, we must limit ourselves to those major aspects that are very well established. What we call "ingraved in stone".

It's a fact that when something reaches a college-level textbook (to say nothing of high-school-level) it is no longer a subject of active research.

DanZ

[Jose]

But if I may put in my 2 cents, I think what's wrong with the teaching of evolution is probably the same thing that's wrong with high-school/secondary level teaching elsewhere: students are not taught to think.

I don't think it is possible to tech students to think. IMHO in school you get out of it what you put into it. I think that is true everywhere, but hidden by the differing cultural assumptions.

If I may disagree (and I mean this in the most constructive way), I say pffffffffft! to that. It actually is possible to teach students to think, and it is possible at very young ages. There is actually considerable data on this. OTOH, your HO is absolutely correct: you do get out of school exactly what you put into it. The problem is that what you put into it is colored by your cultural assumptions (as you say), your surrounding stimuli, the excitement (or lack thereof) of your classes, and whether you perceive your classes as giving you any value. Where I live, the prevailing cultural assumption is that school is a waste of time. The surrounding stimuli are video games, drugs and alcohol, and the like. School is uniformly uninteresting, and the material taught doesn't seem relevant to the students. These factors combine to produce a profound boredom, to which we have responded (seemingly nationally) by cutting school funding and demanding multiple-guess tests.

I am a radical heretic as far as US public schools are concerned. I don't think there is anything wrong with them. I find it interesting that over the period where nearly everyone has been wailing and gnashing teeth about how awful our schools are that the US achieved near universal dominance in all areas of science and engineering.

But keep in mind that the near-universal dominance in science and engineering is based on the achievements of established scientists and engineers, not the achievements of those currently in K-12 schools. In the last few decades, the US share of scientific publications has declined. The numbers of students pursuing higher degrees in science has declined. Our standing in the TIMSS studies is not great. Students are entering college with less and less background--they even turn in work spelled in text-messaging shorthand. This has become more pronounced even in the last decade. So, there are problems, and they are complex.

The solution, as I see it, is as described in the National Academy's National Science Standards: teach differently. "Differently" means less memorization of Science Words and more reasoning from data--that is, give the students opportunities to think like scientists in school. We need to add to it a commitment to building instruction around issues that students recognize as Things That Happen In Life, rather than "just stuff for school."

As far as evolution is concerned, we cannot expect high school students to digest the full implications of the theory. In science every field, sub-field, and sub-sub-field fades off into the areas where we currently don't have the answers. It's there where the details, and the difficult questions, lie. In schools, in textbooks, and in the guidance for teachers, we must limit ourselves to those major aspects that are very well established. What we call "ingraved in stone".

It's a fact that when something reaches a college-level textbook (to say nothing of high-school-level) it is no longer a subject of active research.

You are right that we can't expect high school students to internalize all of the subtleties of evolution, or any other field. However, we can help them understand some of the data and some of the reasons that we have reached the conclusions we have. It is actually a disservice to students to give them only the conclusions. It leads students to think that science is a dead field, in which nothing is going on.

In fact, there is a great deal of active investigation in many of the sub-fields that are reported in textbooks. That's one of the reasons that we periodically find things in texts that are wrong. We thought they were right when they first entered texts, but newer research has given us new insights. In evolution, of course, there is a huge amount of research activity that just hasn't made it into the texts yet.

[ST88]

If I may disagree (and I mean this in the most constructive way), I say pffffffffft! to that. It actually is possible to teach students to think, and it is possible at very young ages. There is actually considerable data on this. OTOH, your HO is absolutely correct: you do get out of school exactly what you put into it. The problem is that what you put into it is colored by your cultural assumptions (as you say), your surrounding stimuli, the excitement (or lack thereof) of your classes, and whether you perceive your classes as giving you any value. Where I live, the prevailing cultural assumption is that school is a waste of time. The surrounding stimuli are video games, drugs and alcohol, and the like. School is uniformly uninteresting, and the material taught doesn't seem relevant to the students. These factors combine to produce a profound boredom, to which we have responded (seemingly nationally) by cutting school funding and demanding multiple-guess tests.

I think you hit it right on the head here. There is a class division among students who are being taught how to think and those who are being taught what to think. There is one variable that outpaces all the others when evaluating student performance in terms of post-graduate (K-12) success, and that's teacher quality. There are many textbook publishers who don't want to face this -- instead of advocating for better recruitment of quality people, educators in power would rather trust the textbooks and curricula that the successful teachers use in order to replicate their success. It's easier, less controversial, and less expensive. As is acceeding to the demands of those who are easily miffed.

The "school is a waste of time" lobby has always struck me as having a general misunderstanding about the purpose of school. I would hazard a guess that a vast majority of parents still believe that algebra will never be used in the real world, so it must be a waste of time. Why should we study the actions of dead people from history? Why learn about genetics when that will never be of any practical use for 99% of the student body? I think many people believe in a direct cause-and-effect relationship for education that doesn't seem to add up to how the real world operates. Unfortunately, such thinking gives us the O.J. Simpson jury, who apparently didn't understand DNA. It also gives us a president who does not understand the purpose of studying history to avoid its mistakes and heed its lessons. It also gives us a debt-laden populace who doesn't see a need to stop spending when there's so much credit available.

But even setting aside all that, the practical application theory of education is a slippery slope that causes education to focus on trades instead of learning. Literature education, practically speaking, is useless and an argument can be made that it is harmful. The same things can be said for music, most athletics, foreign languages (except Spanish here in California & other places), physics, chemistry (outside the kitchen), anatomy, calculus, and many other subjects. By allowing a culture that focuses on the practical effects of education, we are encouraging the idea that many subjects are worse than useless and can therefore either be eliminated or tinkered with in order to make them "useful". Creationism encourages belief in God and therefore will save souls. You can't get any more practical than that. In other words, I don't think that the problem is that the subjects are or are not "relevant" to the students, it's that this relevance argument is tolerated and even encouraged by the larger society. And since it's not relevant, it must be adminstered as a rote memorization exercise, where producing citizens who have the singular ability to take in cold information and spit it back out is more important than producing citizens who can think for themselves. What better type of population is there for a consumer-based retail capitalist culture?

[Titan]

Ah, but we do. Think for yourself what an organ evolving into another organ would look like. It might go through a period where it wasn't doing anything in particular. It lost it's old function and hadn't yet achieved a new one. Hint: think apendectically.

The animal with that trait would die out, remember natural selection.

Ah, but are they good chapters? They usually start with "evidence for evolution" and then go to vague examples of "directional selection" and "disruptive selection" without ever telling us how changes in DNA sequence can actually cause phenotypic changes that selection can act upon. Most people come away thinking it's pretty vague.

The book begins with the history of evolution. It does talk about directional selection and disruptive selection but in the context of natural selection (my book is on www.biology.com, if you wanted to see it, it is the fifth edition). They talk about point mutations in relation to DNA resequencing along with a few other things.

Formations? As in limbs and eyes and stuff? Or as in rock formations? I'd guess the former--in which case I'd suggest that the answer lies in the gradual disappearance of embryology from most biology classes. We need to put it back in. With the advent of molecular genetic techniques, we've figured out a lot, and can describe these things much more clearly. This makes evolutionary change in these structures much easier to understand.

I've always had a problem with embryology because I would expect them all to look similar. Think about it, the organism needs to develop certain organs in order, they are living in a fluid filled sack so they need gills. The thing that I find fascinating is that if they are so similar then why doesn't a bird embryo become a human once in a while. I realize that this sounds inane, I think so to. But you have to understand that differences in DNA are still fairly big. Look at the difference between man and monkeys. We have a high rate of protein similarities but we are still quite different.

Still, there are enough examples of so-called living fossils that we can infer that many environments have been fairly stable.

Another oddity. The horse shoe crab has evolved very little over the span of many generations. Why is that? Shouldn't the organisms that are evolving more win out in the end? Shouldn't the horse shoe crab have to constantly adapt?