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Thursday, July 22, 2010

National Academies: Conceptual Framework for New Science Education Standards

The National Research Council of the National Academies (USA) has published a draft proposal of Core Ideas in science [Standards Framework Preliminary Draft]. These are supposed to serve as guidelines for educating students about science. One of the Core Ideas in Life Sciences is evolution. Here's the complete description.
Biological evolution explains both the unity and diversity of species. Biological evolution results from the interactions of (1) the potential for a species to increase its members, (2) the genetic variation of individuals within a species due to mutations and recombinations of genes, (3) a finite supply of the resources required for individuals to survive and reproduce, and (4) the ensuing selection by the environment of those organisms better able to survive and reproduce. Organic evolution, and the net result of speciation minus extinction, has led to the planet’s biodiversity and ecosystem functioning. Sustaining biodiversity is essential for the maintenance and enhancement of the human population’s quality of life.

The fossil record provides evidence of different life forms at different periods of geological history. This evidence supports the idea that newer life forms descended from older life forms, a phenomenon that Darwin aptly called “descent with modification”. DNA provides further evidence for lines of descent from ancestral species to later-appearing species.

Genetic variation of individuals within a species gives some individuals an advantage to survive and reproduce in the conditions of their environment. This leads to the predominance of certain inherited traits within a varied population. When an environment changes, there is a subsequent change in the supply of resources or in the challenges imposed by abiotic and biotic factors of the environment. This results in selective pressures that influence the survival and reproduction of organisms and which lead to adaptations, that is to changes in the traits of survivors within populations, and to extinction of species unable to adapt to such changes. Mutations most often produce non-viable individuals, but, infrequently, can introduce new traits within a population that offer survival advantages. Many such changes, along with reproductive isolation and the selective pressures from the environment can lead to the development of adaptations and, eventually, to distinct new species.

Biodiversity – the diversity of genes, species, and ecosystems – provide humans with renewable resources such as food, fuels, fertile soils, clean water and air, medicines, as well as surroundings (from species to landscapes) of inspirational value. The resources of biological communities can be used within sustainable limits, but in many cases the human impact is exceeding sustainable limits.
Contrast this adaptationist and environmentalist view with the description of evolution in Futuyma (2009)—one of the leading textbooks of evolution.
1. Evoluion it the leading principle of the biological sciences. Evolutionary biology aims to discover the history of life and the causes of the diversity and characteristics of organisms.

2. Darwin's evolutionary theory, published in The Origin of Species in 1859, consisted of two major hypotheses: first, that all organisms have descended, with modification, from common ancestral forms of life, and second, that a chief agent of modification is natural selection.

3. Darwin's hypothesis that all species have descended with modification from common ancestors is supported by so much evidence that it has become as well established a fact as any in biology. His theory of natural selection as the chief cause of evolution was not broadly supported until the "evolutionary synthesis" that occurred in the 1930 and 1940s.

4. The evolutionary theory developed during and since the evolutionary synthesis consists of a body of principles that explain evolutionary change. Among these principles are (a) that genetic variation in phenotypic characters arises by random mutation and recombination; (b) that changes in the proportions of alleles and genotypes within a population may result in replacement of genotypes over generations; (c) that such changes in the proportions of genotypes may occur either by random fluctuations (genetic drift) or by nonrandom, consistent differences among phenotypes in survival or reproductive rates (natural selection); and (d) that as a result of different histories of genetic drift and natural selection, populations of a species may diverge and become reproductively isolated species.
These are very different descriptions of one of the core ideas in the life sciences and they don't agree. Which one do you think is better—the one written by a committee 23 people for the National Academies or the one written by Douglas Futuyma? Which one supports good science education and critical thinking?


  1. I'm not completely happy with either one. I think that evolutionary theory seeks to explain *three* things - unity and diversity (as the National Academies proposal says) plus "adaptedness".

    I would be happy with allowing the academy to emphasize NS as the major or sole explanation of adaptedness if they would just back off a bit on using it as the sole explanation of diversity.

  2. Futuyma is equally adaptationist and microevolution-focused, I'd say...

  3. Nick,

    That's not the point. The point is that Futuyma represents evolution correctly no matter what his personal bias. Futuyma is not confused about the difference between evolution and natural selection. He includes random genetic drift as an important mechanism of evolution.

    The Ontario high school curriculum also teaches random genetic drift. Why did this committee leave it out when it is, beyond doubt, one of the core conceptual frameworks of biology?

    Futuyma doesn't mix his science with statements about how it affects humans and how humans should behave towards the environment and towards other species. Futuyma knows that this isn't part of the conceptual framework for science. Why is the committee confused about this?

  4. Larry asks: "Why is the committee confused about this?"

    Perhaps because the committee consists of 17 members, 2 of whom have training in biology. A Drosophila geneticist and an ecologist who specializes in rainforest species loss.

  5. "Mutations most often produce non-viable individuals."

    I guess we're all dead then.

  6. The objetive and target audience are different.

    Futuyma gives a definition.

    The Academy provides guidelines on a whole topic to further elaboration on class. Application and biodiversity are ON topic.

    However, factual errors are not. I agree that the words on mutation plus the lack of mention of randomness (including drif) does nothing to avoid the fallacy of purpose.

  7. It seems disgraceful to be trying to produce science standards with so few active scientists on the committee.

    I see that they did have one person on the committee who has thought a lot about evolution, Marc Kirschner, but he resigned early in the year ( -- wonder why.