kitchen table math, the sequel: metamorphosis

Sunday, July 12, 2009


Remember the adults' explanations of metamorphosis they fed us during kindergarten to second grades? Somehow we were content with talk of how the caterpillar forms its chrysalis, "goes to sleep" and wakes up a butterfly.

Metamorphosis seemed to be taught on a really funny "spiral". I don't know how frequently other American elementary schools do it, but for 3 consecutive years my classroom teachers would run the growing-Monarch-caterpillars-on-milkweed experiment, with a multitude of variations (like growing several in the same lifebox).

Then they don't touch metamorphosis for 10 years (no, I'm not counting Animorph novels) and you rediscover its study in college in some neurobiology or developmental biology class.

Why is the popular image of evolution that of primates slowly transforming to humans? (Not to say how Lamarckian this picture is.) The picture to capture children's minds with is that childhood storybook of the tadpole and the frog.

It's intuitive to children. The frog starts out as a tadpole because it is an amphibian, and amphibians once came from a fish-like ancestor who had to come onto land. Every time the tadpole grows legs, loses its gills, and gains lungs, it is re-enacting that ancient evolutionary event. A shocking argument to first-timers -- and yet, they are pulled in -- because when you really think of it, some more pieces of the puzzle of the world suddenly seem to fall together.

As a child, I remember two thoughts about metamorphosis:

1. Wow, it's really cool! Flightless animals can gain functional wings! I wonder if I can learn a way to do it myself. Being able to fly would be pretty cool.

2. Wouldn't it be easier to just start out a butterfly?

I can't remember what my teacher said about 2), but I seem to have the impression that my inquiry was cruelly quashed. Luckily 1) was there to continue my interest in the life sciences.

Instead of cutting out paper butterflies or learning the umpteenth reading strategy, I wonder if it's possible to try out the following in the lower grades:

i. some more details you know, about the transformation. Young children learn what a heart and a liver is, as well as some of the details of gestation. It really expands your mind about what an individual organism is, when you learn that the caterpillar practically gets dissolved by its own pool of digestive juices, and a butterfly is reassembled from the soup of nutrients by special stem cells. (Kid-friendly explanation here.)

ii. some attempts at a why. It would be nice. It almost gets glossed over in the lower grades (or in high school, for that matter) that a caterpillar happens to be particularly good at eating, and a butterfly happens to be particularly good at mating and laying eggs in faraway places. I believe one of the comments to the Youtube video above is, "Why can't the strangler fig grow its own trunk?" It's even missing in Singapore's PSLE science syllabus -- you learn about complete and incomplete metamorphosis and the finer details of exotic life cycle archetypes, from spinning wind-borne angsana fruit to cockroaches -- but nothing about why it's advantageous to be so "weird".

iii. a greater exhibition of the plasticity of life. Fundamentalist resistance to evolution in school continues to persist for several reasons, some of which are because of the inflexible picture of life children get very early -- cows will always moo, dogs will always bark, the roles of each are fixed and immutable. Look at that cat! It's so different from a bird -- what ancestor could it possibly share with it?

iv. Some updates on cellular bio would be nice. I remember two pieces of "info" from childhood science classes: the cell is the basic building block of life. (Whatever that means.) Genes are blueprints. I do think children should deserve better than that. If you told them instead, that cells are tiny materials and machinery builders capable of producing more of themselves, and that genes were more like instruction "how to" manuals that cells read, a lot of things would make more sense. (A caterpillar doesn't "die" per se while its being digested in the chrysalis because some cells still carry its instruction manuals.) It would also have saved me a lot of the, "BUT where is the blueprint for our arms, teacher? What does it look like?" questions.

But we could also reject the idea that teaching content is teaching reading, and teach children how to make glittery power point slides instead.

1 comment:

Anonymous said...

A better allegory for our government's relationship to the economy would be hard to find.

It's not bad for public ed and knowledge either.