Introducing: Horseshoe Crabs in the Classroom, Take 2


During the 2011/2012 school year, we had a program called Horseshoe Crabs in the Classroom at our elementary school. This program is offered through the Maryland Department of Natural Resources and it's a great idea for a number of reasons - letting kids learn about these incredible pre-dinosaur animals while, maybe, helping add a few more of these amazing animals to the Chesapeake Bay.

Last year, we ended up with no live horseshoe crabs (HSC) and I think this was because of over-zealousness on my part for ridding the aquarium of an unwanted fungus or at least what I thought was fungus. The 4th graders, though, were very enthusiastic and they learned a lot about the critters even though they never saw a live one in their classroom. Sigh.

This year, though, now that the teacher (me) is a bit more experienced, I think we'll have better luck. So here's Take 2...

Thursday, July 19, 2012

July 19 - Swimming in slo-mo and body parts


http://www.youtube.com/watch?v=sCtAv7fU1lc

I love this youtube video! It's a terrific look at the coordination required for horseshoe crabs to swim. They are really beautiful swimmers and they use their book gills and all 10 legs flapping together. It's pretty amazing. This should work when you click on the button but right now it doesn't seem to. I'll work on that.





Another one of my videos of horseshoe crabs swimming in a white spoon. I'm trying to figure out what stage these little fellows are at. Obviously not eggs, so they're some stage of larval development. Eventually, they will have their long tails but not yet. I thought they had the start of their tails (telsons) but I'm not so sure. So I've done some research. To understand this, you'll need to know something about horseshoe crab segments or body parts.






Horseshoe crabs are divided into three parts: the prosoma which is the big round part, the telson or tail, and the opisthosoma which is between the telson and the prosoma and has the book gills and the spikes on the outside of the body.

Here's a photo I took today of a larva (again in the white spoon):  




Here's a google image (not my photograph but they look pretty similar:

http://www.city.kobe.lg.jp/information/public/online/photo/number18/english/small_features/index3.html

The site of the google picture describes this as a "first instar larvae." That's a pretty fine name! So I'm going to conclude that whatever the name, there's not yet a larvae with a telson. Prosoma, yes, and opisthosoma, yes - but no telson yet.

And that's the end of this lesson! 


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