Biology – Dissection lab

by Darla on September 4, 2009

in Science

For the past couple weeks we’ve been keeping ourselves out of trouble with a co-op of sorts. Another family we know was interested in doing dissections, which I was but wasn’t if you know what I mean. It was just one area that I thought my kids would miss because I didn’t feel confident enough to wing it, I’ve since changed my mind. We could have done this and I don’t know why I was such a chicken about the whole experience.

This is a general over view of our activities and materials used.

We started with the Intermediate dissection kit -worth the price.  (Fetal pig was a bit overwhelming to me) http://www.hometrainingtools.com/dissection-kit-intermediate/p/DE-KITINT/

Intermediate Kit Contents:

  • frog (2.5-3″)
  • perch (4-7″)
  • crayfish (3-4″)
  • grasshopper
  • earthworm (6-8″)
  • clam (4-5″)
  • starfish (3-5″)
  • 6 dissection pins – I ordered an extra box which I needed with the frog
  • 17 piece tool set
  • reusable pan
  • Dissection guides
  • How to Dissect guide by William Berman *** This was a valuable resource and worth the $

BK-BERMAN

Our Biology Text – http://www.apologia.com/store/index.php?main_page=index&cPath=4

Other supplies:

  1. Cheap plastic table cloth
  2. Foam disposable plate
  3. disposable gloves
  4. Face masks (optional)
  5. Optional microscope for starfish but not required
  6. garbage bags
  7. small garbage can
  8. area to clean up.  It is best to get this prepared ahead of time.
  9. paper towels
  10. foam plate with wet washcloths

What I learned:

Don’t be afraid.

Start with the simplest item first – usually the earth worm and work your way to more complicated.

A dissection guide is essential.  I can’t recommend the one above enough.  When our textbook had the dissection in it that was better.  It had color photos and the directions were more concise in my opinion.  The color photos helped us to identify the parts in our specimens better.  The crayfish directions were fantastic.While it was nice to have the kit, it would be nice to have extra samples for each activity.  Especially, the grasshopper, clam, and crayfish.  This is great for compare and contrast.Our experience:  We had three kits from the above company.  Not sure if they come from the same source or not.  The specimens were quite different.   Had we not had the variety from the 9 specimen kit and the 7 specimen kit I might have gotten frustrated easily.  What we couldn’t see in one specimen we saw in another.

There is a time limit as to how long you can wait to do the dissections even using the ziploc bag as suggested.  We did these over a period of 4 weeks.  For the fish that was stretching it.  It was tough smell wise.  It might be better to just get a fresh fish from your local market that hasn’t been gutted.

The Grasshopper was difficult because it was fragile so we needed a few more samples.  Not only for dissection but to determine whether it was male or female.  The book suggested 4 – 2 males and 2 females.  Not sure if the company allows you to specify which you want.

The crayfish took time but it was worth the effort.  Here is an interesting point.  We had a smaller specimen and at first I thought that was a sad thing, it might be harder to see the details.  Nope, the larger ones were more difficult.  They were discolored inside and so all the parts tended to blend together.  Smaller was better although harder to dissect without damage.  We saw what we wanted to see and then explored on our own.

The Clam, in my opinion, wasn’t worth the effort.  I would not do it again.  I don’t know that we learned that much other than it was tough to open.  We did not see what the dissection book suggested in any of the samples.

The Perch and frog were incredible and I really enjoyed that.

The Starfish was interesting but quite difficult to cut through the exoskeleton.  I ended up doing most of the cutting.  Our friends had an easier time of getting the outer surface off to expose the inside without damage.  Our sample didn’t work that way.  So again if one doesn’t work another might.  Our sample also had a darker appearance while theirs looked alive in color.  I kept waiting for the arms to move.  Even if we hadn’t dissected it to see the inside, it was fascinating to see this particular piece and worth the effort to purchase one.

Order matters.  it was better to follow the dissection guide and then pull things apart when we were finish to observe the rest or have a second sample so the kids can pick and pull apart and then have another one to go back to if the first one is trashed from their observation.

We took detailed photos since we are doing the labs all together.  Then when we get to the unit in our book, we will be able to refresh our memories.

Purchasing the specimens individually means they are packaged individually and there might be a greater opportunity to spread the dissections out over a year.   Our large package had a small puncture and so it couldn’t wait.

Now that we’ve completed our primary lab, I’m intrigued enough to purchase the cow eye, dogfish shark and squid.  I will probably purchase a larger fish from the docks to dissect with the kids so it will be fresh.

http://www.biologyjunction.com/fetal_pig_dissection.htm

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