Thursday, January 30, 2014

Understanding, not Belief, in the NGSS Evolution Standards for High School

Image from here
Finally got some time, thanks to Snowmageddon '14 here in Birmingham, to dedicate some time to examining how the Next Generation Science Standards approach the teaching of evolution. I had looked briefly several times before, but I needed some think time before putting an analysis for your review and reaction. (I definitely got that think time when my whole city shut down for 2 days.) I look forward to your feedback, especially if you see the NGSS differently than I do.

Bottom line: The NGSS do not require belief in evolution. And that's really good news for teaching evolution in the South and other areas of the country where students resist learning about evolution. It's also really good news for public school parents, science teachers, and anyone developing curriculum documents. The NGSS keep public school classrooms safe for students who see a conflict between evolution and their faith.

Let's look first at the high school evolution standards from the NGSS. I'll analyze them standard-by-standard below, but I suggest that you first take a couple of minutes to review the standards as they are presented together. As you probably know, the NGSS are purposely written to fit many, many features together in each standard set.  At the bare minimum, they intertwine content and process so that science teaching in America can no longer divorce the two. If you haven't seen it already, also make sure to see how the clarification statements and assessment boundaries help science teachers see the level of rigor NGSS is targeting for teaching evolution.

Now, looking standard-by-standard for belief versus understanding:

HS-LS4-1 Communicate scientific information that common ancestry and biological evolution are supported by multiple lines of empirical evidence. [Clarification Statement: Emphasis is on a conceptual understanding of the role each line of evidence has relating to common ancestry and biological evolution. Examples of evidence could include similarities in DNA sequences, anatomical structures, and order of appearance of structures in embryological development.]

Clearly, this standard makes no requirement students believe in evolution. As I have advocated for years, this standard grounds students' work strongly in evidence by having them look at multiple lines. Then, they are to be able from that to "communicate scientific information" about evolution, and I hear in that portion of the standard a clear focus on students' understanding and communicating key science ideas without requiring any kind of belief from them.

HS-LS4-2 Construct an explanation based on evidence that the process of evolution primarily results from four factors: (1) the potential for a species to increase in number, (2) the heritable genetic variation of individuals in a species due to mutation and sexual reproduction, (3) competition for limited resources, and (4) the proliferation of those organisms that are better able to survive and reproduce in the environment. [Clarification Statement: Emphasis is on using evidence to explain the influence each of the four factors has on number of organisms, behaviors, morphology, or physiology in terms of ability to compete for limited resources and subsequent survival of individuals and adaptation of species. Examples of evidence could include mathematical models such as simple distribution graphs and proportional reasoning.] [Assessment Boundary: Assessment does not include other mechanisms of evolution, such as genetic drift, gene flow through migration, and co-evolution.]
I've summarized inquiry for many groups of science teachers as a cycle of evidence and explanation. This standard solidly directs students toward understanding evolutionary processes in an inquiry approach. They build explanations out of evidence, and teachers can guide these explanations away from belief controversies by keeping them focused on scientific explanations and how those are limited to natural processes. The standard clearly supports this with its four factors, all of which are natural processes.

HS-LS4-3 Apply concepts of statistics and probability to support explanations that organisms with an advantageous heritable trait tend to increase in proportion to organisms lacking this trait. [Clarification Statement: Emphasis is on analyzing shifts in numerical distribution of traits and using these shifts as evidence to support explanations.] [Assessment Boundary: Assessment is limited to basic statistical and graphical analysis. Assessment does not include allele frequency calculations.]
A focus on natural selection, as in this standard, typically doesn't cause resistant students nearly the problems they face when they are asked to look at evolution across millions of years. So belief shouldn't be an issue with this standard.

HS-LS4-4 Construct an explanation based on evidence for how natural selection leads to adaptation of populations. [Clarification Statement: Emphasis is on using data to provide evidence for how specific biotic and abiotic differences in ecosystems (such as ranges of seasonal temperature, long-term climate change, acidity, light, geographic barriers, or evolution of other organisms) contribute to a change in gene frequency over time, leading to adaptation of populations.]
Same as the Standard 3 above--natural selection typically doesn't raise belief issues.

HS-LS4-5 Evaluate the evidence supporting claims that changes in environmental conditions may result in: (1) increases in the number of individuals of some species, (2) the emergence of new species over time, and (3) the extinction of other species. [Clarification Statement: Emphasis is on determining cause and effect relationships for how changes to the environment such as deforestation, fishing, application of fertilizers, drought, flood, and the rate of change of the environment affect distribution or disappearance of traits in species.]
With a focus on "emergence of new species," this standard will probably be the most difficult of the six for resistant students. Typically, they resist evolution because they simply do not believe new species can emerge on their own without supernatural influence. (I actually agree with them, and many practicing scientists agree as well.) But, clearly, this standard does not focus on changing students' beliefs. They are not to "accept the evidence supporting claims..." Instead, they are to "evaluate the evidence." Interestingly, I actually think this standard left a door wide open for a Teach the Controversy approach, which I am quite sure the NGSS authors did not attend.
Create or revise a simulation to test a solution to mitigate adverse impacts of human activity on biodiversity.* [Clarification Statement: Emphasis is on designing solutions for a proposed problem related to threatened or endangered species, or to genetic variation of organisms for multiple species.]
Again, clearly a focus on natural selection, since it's limited within the short time frame of human activity, and not one raising the specter of belief change.

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