What Grade Niners are learning is settled science?

When I was in high school I was taught the electron shell model of atoms. This is not correct as I found out later. But it's a good place to start and it helps students to start heading off in the right direction. Later, when their mathematical skills are up to the challenge the more advanced model is introduced. I think it's quite common in the sciences for simple models to be introduced in order to get the learning started. I'm not sure what the problem is here. Jerad

This post raises an excellent (read: difficult) point, which revolves around biology's very complexity and messyness. In practice (as Denyse notes), it's nearly impossible to make ANY general statement about biology for which there are no exceptions, nor is it generally possible to reduce any process to greater simplicity without losing perhaps more in detail than is gained in comprehensibility! For that matter, although I am certainly not a biologist, I have never heard of a single instance where natural selection acting alone is responsible for any adaptation or speciation. And this, I have read, is true for the simple reason that in the messy biological world, natural selection simply does not act alone, anywhere. Instead, many forces and trends interact in complex ways difficult to model accurately. So what's raised here is not an objection to evolution, of course, but rather an excellent point about the difficulty of presenting what is known about evolution in a form both simple enough for those encountering it for the first time to absorb some of the ideas, yet not so simple that what is presented isn't too misleading. Still and all, the goal (not always achieved, I think) is that scientific material in high school text books should be carefully vetted. I recall vaguely that some study a while back found numerous errors of fact in most textbooks. Not errors of interpretation (like "what caused WWI?") but simple wrong facts. Since most textbooks are largely copied from earlier textbooks, errors can propagate for discouratingly many versions. It seems to be the case that in the world of biology, nothing is ever entirely "settled science", nor is this the case in any scientific field. But learning science or anything else has to start somewhere, so it starts with the most widely accepted and least controversial illustrations. The Viceroy butterfly is a Mullerian mimic of the Monarch, but not a Batesean mimic. These are not mutually exclusive, however. Both types of mimicry result from natural selection, but along somewhat different paths. And this is a very good example of how even simple illustrations, when examined at all, rapidly exceed the capabilities of 9th graders. David W. Gibson