Sunday, April 4, 2010

Taxonomy and the Animal Kingdom: Annelids and Vermicomposting

"These ambiguities, redundancies, and deficiencies recall those attributed by Dr. Franz Kuhn to a certain Chinese encyclopedia called the Heavenly Emporium of Benevolent Knowledge. In its distant pages it is written that animals are divided into: (a) those that belong to the emperor; (b) embalmed ones; (c) those that are trained; (d) suckling pigs;(e) mermaids; (f) fabulous ones; (g) stray dogs; (h) those that are included in this classification; (i) those that tremble as if they were mad; (j) innumerable ones; (k) those drawn with a very fine camel's-hair brush; (l) etcetera; (m) those that have just broken the flower vase; (n) those that at a distance resemble flies."

-Jorge Luis Borges, The Analytical Language of John Wilkins


"Worms are the intestines of the earth."

-Aristotle, The History of Animals

I believe that Montessori's method for presenting the natural sciences to young children may be one of her most important discoveries and really demonstrates her respect for their intelligence, aptitude, and competence. One of the things that I particularly like about it is the comprehensiveness and systematicity of the curriculum. Montessori believed that the 3-6 year old child is in the process of making sense of the world by organizing their sensory impressions. She envisioned the young child in much the same way that we might envision a philosopher who begins by exploring the world (ontology) and then seeks to establish a logical order and arrangement for what they have discovered by classifying various modes of "Being" according to the ways in which they are different from and similar to one another.

To aid children in this process of exploring and understanding the natural world, the 3-6 Montessori curriculum presents children with a comprehensive overview of the natural world by moving through the biological taxonomy and by offering children concrete sensory experiences with the objects of their study. In addition to providing children with a strong foundation in science, this method also teaches very young children to employ a very high level of logical reasoning. At a very young age, children are taught to make repeated observations, to compare and contrast experiences, make and check predictions, and to interpret and communicate their findings. Additionally, children are able to sort specific objects based upon abstract principles into a complex classification scheme and children are familiarized with a tree structure of classifications in which reasoning proceeds from the general to the specific and all the concomitant logical operations (e.g "Dogs are mammals; all mammals have live offspring. Therefore, dogs have live offspring").

This April, the children have just concluded their unit on the Fungi Kingdom and have begun learning about the Animal Kingdom. We have begun our study of animals with they Phylum Annelida (segmented worms). Worms are a perfect object of study for children this age because they are ubiquitous. As a result, the children have ample opportunities for empirical observation.

We began our unit of study with a trip out to the garden. We dug up a small plot of dirt to learn about the animals that live there. The children were very excited to find earthworms, millipedes, pill bugs, and even baby worms and earthworm cocoons! Our mini- oligochaetologists used magnifying glasses and rulers to closely inspect and measure their specimens before releasing them back into the garden to watch them squirm into their burrows.

Afterwards, we went about assembling a classroom vermicompost bin. Vermicomposting is composting using worms. Worms can eat their own body weight in organic waste every day; in fact, one pound of worms can convert 1.3 million pounds of waste into high quality fertilizer in about 60 days. The waste that worms produce (referred to as worm "castings") has five times as much nitrogen, 7 times as much phosphorus, 11 times as much potassium, and 1,000 times more beneficial bacteria than the soil or organic matter they consumed in the first place. Research shows that plant yields benefit tremendously from vermicomposting (broccoli as much as 40%, tomatoes as much as 80%, and carrots as much as 259% according to new research in The Ecologist); additionally, the castings prevent plant diseases (such as the dreaded blossom end rot that got our tomatoes last year) and fix heavy minerals to reduce leaching in the soil. Scientists have even found that their digestive systems are so remarkable that they can consume hazardous waste (volatile organic compounds) and yet emit toxin-free castings.

It turns out that vermicomposting is en vogue at the moment. We bought some wholesome Midwestern vermis and a pre-fabricated vermicomposting set up from La Verme's Worms, a little family cottage industry in Duluth Minnesota.

To set up the bin, we mixed peat moss, sand (worms have no teeth and have to depend upon sand in their gizzards to grind up their food), limestone, blackstrap molasses!, and "worm juice" (a concentrated liquid fertilizer consisting of worm effluent, which is high in symbiotic microorganisms) together to use as worm bedding.

Then we added one pound of Eisenia Fetida (a.k.a "Red Wiggler" worms). There are more than 3,000 known species of earthworms. Scientists like to classify earthworms according to their function. Large earthworms, like the ones the children dug up in the garden, are called anecic worms. These worms build permanent burrows in their soil, depositing their castings at the openings. They can burrow as deep as eight feet and do an excellent job of tilling soil and increasing drainage. Our little red wiggler worms are significantly smaller; they are considered epigeic worms. They live near the surface, in the leaf litter layer of the soil, where they are highly efficient decomposers and deposit nutrients that help plants germinate and grow.

Finally, the worms are covered with a layer of dry leaves and a black sheet (to help keep out the light).

And voila! Meet the newest class pets... over 1,000 voracious vermis!

I must admit that I wanted to incorporate the study of Annelids primarily for the sake of comprehensiveness (it would have bugged me to cover the taxonomy and leave them out) and because they are such simple creatures, thereby providing a very basic introduction to anatomy, and not because I really loved worms. Honestly, Josh had to practice with me a few times before I could hold them in my hands without getting a mild case of the heebie jeebies.

What changed my perspective on worms? Charles Darwin.

Over Spring Break, I happened to read a very interesting book entitled The Earth Moved: On the Remarkable Achievements of Earthworms by Amy Stewart. It turns out that after travelling for five years around the world on the Beagle, and studying beautiful, exotic, specimens, what captured Darwin's attention for much of the remainder of his life was the lowly garden variety earthworm. In fact, Darwin wrote a nice little treatise about earthworms entitled On the Formation of Vegetable Mould, in which he meticulously recounts his experiments on earthworms (everything from placing them on the piano so that he could determine whether they responded to vibrations, to pulling 227 worms out of their burrows to see if they were dragging dead leaves in by their tips or their bases, to reconstructing pine needles and cutting paper triangles and coating them with fat to study whether the worms would pull them in by their apexes or bases). Based upon his research, Darwin credited earthworms with conscious problem solving abilities (more than 80% used the apex, as Darwin determined they should, with very little fumbling or trial and error) as well as being highly beneficial to the earth and preserving much of antiquity for archaeologists. As if that was not enough, earthworms have been used to help substantiate the theory of transcontinental drift (the presence of like species on different continents follows the pattern of the theory, and because worms live in the earth, and cannot get across bodies of saltwater by themselves, they are uniquely suited to document the theory in a way that other creatures are not).

One of the pleasures of being around children is that we are re-introduced to the things around us and we get to experience a little bit of that wonder that is unique to childhood. After finishing the book, which I highly recommend to anyone with a spare afternoon, I must say that I find myself both intrigued, and even quite fond, of them.

The children were very interested in them. It is rare that more than a couple of hours goes by without one or more children opening the bin, holding a wriggling worm in the palm of their hand or feeding them scraps from the compost bin. I was particularly amused by two of the little girls who rarely observe them without whispering "Aren't they cute?" to each other.

Indeed, I ask you... "Aren't they cute?"

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