Our pillbug tank (which also has slugs, and once held centipedes and soldier flies) has a new crop of newborns. Despite the dangers of sophomore handlers ("I guess I kinda accidentally dropped a rock"), our tank has as at least as many critters as we started with back in September.

They will be returning to the wilds of Bloomfield soon, and it's all good.

Almost.

Yesterday two snails emerged from the tank litter, slowly slithering their way towards a flake of fish food. We never had snails before. None.

And if my lambs are thinking, and they are truly open-minded,and if they trust that no one snuck in and put the snails in there, well, we have some evidence for spontaneous generation.

Further complicating this are the fry that hatched months ago. While most died (as expected), we have about 15 left, and they look less and less like their parents. Oh, they have gills and fins and scales and all that, but they're the wrong color and the wrong shape. (I know about color changes in goldfish--my students do not).

If I have done my job right, a few students will soon announce that we have provided evidence that spontaneous generation happens. If I've really done my job right, those same students will come up with several hypotheses as to how this occurred, and set up an experiment to replicate the results.

Heck, they'll be juniors next year, they can even run the experiment when they get back in September. In the meantime, if a few remain suspicious that maybe spontaneous generation still happens, well, at their age with their experience they should be suspicious. I encourage skepticism.

That's how science works.

No, I don't believe in spontaneous generation. I think....

I also don't believe children should accept what I (or any "experts") say at face value.

READ MORE - Spontaneous generation

Explaining the daphnia was problematic enough, then came the mosquitoes. Now I got a tank full of fish fry darting about with no adult fish in sight.

Yes, of course, I do not believe in spontaneous generation. There must be a reason, and I have a hypothesis or two to explain where the fry came from.

But what do I tell the children?

Children who never saw a carrot develop from a seed before this year?
Children who never saw saw slugs before?
Children who are just starting to trust me when I tell them that the world that matters is the world that they can observe?


I'm not going to tell them anything. An empty tank now has a couple dozen fry, really just eyeballs with a tail attached, cute as can be and not likely to survive the week. I'll let the students figure it out.

My lambs crammed together around the tank, marveling at the tiny critters that started their lives right here in Room B362. They see what they see.

If I tell them what they're supposed to think I'll ruin the whole thing.

The fish fry photo taken from ExoticGolfish.net here.

READ MORE - Spontaneous generation?

I call thee stranger, for the town, I ween,
Has not the honor of so proud a birth-
Thou com'st from Jersey meadows, fresh and green,
The offspring of the gods, though born on earth;
For Titan was thy sire, and fair was she,
The ocean nymph that nursed thy infancy.

--William Cullen Bryant

I witnessed a miracle tonight,
Well, maybe not a miracle, it happens millions of time a day, but today it happened in my classroom.

I saw a pupating mosquito larva erupt into a tiny pale adult.

***

The late January sunset floods the back wall of or classroom. I have a small tank of elodea. A few snail keep the plants company. About a week ago, I noticed a few wrigglers in the tank. I have no idea how they got there. 

Just before I leave, I make my rounds, checking our plants, our roly polies, our snails. I love watching the elodea bubble off oxygen. It's a nice way to end my work school day.

Just under the water's surface, I glimpsed a violent wiggling. A glassine wriggler struggled at the surface, occasionally contracting violently, reminiscent of the last violent transition stage of human birth.

In this tiny universe, the glassine mosquito struggled against the water's skin. The pupa looked like fine crystal, lit by the setting sun and the tiny light above.

I watched for about 15 minutes, until, finally, a pale adult mosquito emerged, paused, then attempted flight. Three times it jumped, three times it came back to the water, with the tentativeness of a newborn foal testing its legs. 

It needs nectar, and it won't find it tonight. I suspect it will be dead by morning.

***

Where did it come from? How do the countless microscopic critters alive in our room find their way here?

I encourage my students to draw conclusions from the observations they make. They now have a decision.

They can trust me when I tell them spontaneous generation does not happen, that all cells come from pre-existing cells, that life only comes from existing life. The ponds outside a frozen, the snow over a foot deep. We have not seen flying insects outside for over a month.

And I have a tank full of wrigglers sitting in the back of my classroom.

Or they can quietly believe in spontaneous generation. For a few moments tonight, as I knelt watching the emerging pale ghost of a mosquito erupt from the water, I would have quietly agreed with them.

The poem excerpt is from The Mosquito, written in the 19th century.
The music is from Jonathan Richman and the Modern Lovers, "I'm Nature's Mosquito"--I'm playing it in class tomorrow.

READ MORE - On the mosquito