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Secular Science Resources for Homeschoolers

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April 2019

High School Biology 28 – Vertebrates

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This week the high school students dissected two dogfish sharks.  These are pretty cool to dissect.  They are fairly large, over 50 cm long from head to tail. You can see in the photo, I placed 3 dissection mats on an old cookie sheet that I use for science experiments.I found a nice handout online that had lots of questions, some of which we had to look up on the internet – new vocabulary words, finding certain organs and details on the shark and even taking measurements.

One of the first things students do is feel the shark skin.  Its nice and smooth if you ‘pet’ it from head to tail, but if you rub your hand in the other direction is feels very rough. This is because the skin is covered with little scales.  We took a sample of the skin and put it under the microscope (40x), you can see the sharp scales below.

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I watched the following videos, posted by South Dakota Public Broadcasting, before class so I would have some idea what we were looking at.

There’s a link below the videos on youtube to other dissection videos and lesson plans/checklists for dissection. Unfortunately the dogfish shark resources have been uploaded yet but they should be up by the end of the summer (2019).  While watching the videos I saw they found fish skulls in the stomach so I made sure to have my students open up the stomach and they found brine shrimp in one of them!  We took the head of one of them and put it under the microscope to look at brine shrimp’s compound eye.

The teeth are also very interesting to look at.  I had two sharks from two different companies and I have to say the dissection specimens from Carolina.com are always the best.IMG_3958

Students were to read Holt Biology, Chapter 25, or Biology: Life on Earth,  Chapter 24 on vertebrates and watch the following video before class:

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Middle School Biology 27 – Frogs & Butterflies

 

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Instead of dissecting a real frog, the students worked on a 3D frog paper dissection model from Getting Nerdy with Mel and Gerdy.  There are a lot of parts to this model, the list of organs and body parts to color is 4 pages long!  Most of the students barely finished the coloring, so we’l finish them up in class next week.  While students were coloring, I read the information pages on frogs and their anatomy.

I also have a plastic simulated frog dissection kit that came with a plastic set of organs and a squishy set – though it looks like it only comes with plastic ones now.   You can see it in the middle of the table in the photo below.

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Over the last month I’ve also been raising painted lady butterflies (Insect Lore)  and we released them this week.  The tiny caterpillars arrive in a small plastic cup with food in the bottom. It takes a few hours/days for them to start moving around but they grow quite fast.

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In just a few days they had doubled in size.

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The cup came with 6 caterpillars and after a week I opened up the cup and put in the butterfly habitat with some branches so they could stretch their legs.  It wasn’t long before they made for the top of the habitat, hung upside down and formed chrysalides (about 10 days after they arrived).

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10 days later butterflies emerged from the chrysalides.  I kept them in the habitat (fed them diluted sugar water) until all my students had seen them and then we released them outside.

 

If you haven’t raised butterflies from caterpillars before I highly recommend it, especially for elementary students.

High School Biology 27 – Arthropods

We started class discussing different types of arthropods (which means jointed foot), such as arachnids, insects, crustaceans and trilobites to name a few.  I had detailed instructions for the high school students for dissecting grasshoppers and a crayfish, while I had kind of let the middle school students wing it and explore on their own. I posted some videos on the middle school post that are good to watch before dissecting your own specimen.  If I hadn’t watched the video for the crayfish, I never would have known to challenge my students to find the gastril mill – teeth like ridges inside the stomach of the crayfish!  We found them and put them under the microscope – very cool!

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grasshopper mandible
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crayfish gastril mill (‘teeth’ like ridges in the stomach!)
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grasshopper wing

This week I had students read Ch 24, Arthropods in Holt Biology or finish Ch 23 in Biology: Life on Earth.  For videos, I sent them a list of True Facts About… by zefrank1, including the ones on Sea pigs, mantis shrimp, leaf katydid, dung beetle, bolas spider and carnivorous dragonflies.  There is some adult language in these videos but they are very entertaining and educational.

I purchased the dissection specimens from HomeScienceTools.  The tools we used were similar to this dissection kit and tray.  I also find the book, How to Dissect by William Berman fairly useful.

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Middle School Biology 26 – Arthropods

Today we dissected a grasshopper and a crayfish.  We first inspected the external anatomy, observing the exoskeletons, compound eyes (simple eyes were hard to see on black grasshopper), different types of legs and the many mouth parts on both arthropods.  Students removed the exoskeletons and found the stomach and intestines in both creatures.  Here are two videos on how to dissect which are very useful as either a substitute for actual dissection or prepartion before doing a dissection.

We put various parts of the grasshopper and crayfish under the microscope and took some photos.

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Crayfish mouth piece
grasshopper compound eye
Grasshopper compound eye
crayfish gills
Crayfish gills
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Grasshopper ‘ear’ – tympanic membrane found near rear legs.

 

Students also completed an interactive notebook activity (found in Classification of Living Things by Getting Nerdy with Mel and Gerdy) on grasshopper body parts –  it had the body divided into three sections, the head, thorax and abdomen and after doing the dissection students listed the important body parts found in each section.

I had saved the sea stars from the high school class last week and showed the students the different parts of the sea star and had them tape a diagram into their notebooks.

 

High School Biology 26 – Invertebrates

Students read Chapter 23 on Invertebrates in either Holt Biology or Biology Life on Earth and watched the following videos before class (and the videos I posted on the middle school post on invertebrates):

Students started class making the 3D earthworm from Getting Nerdy with Mel and Gerdy, which I already described in the  middle school post. The papercraft has students color and describe the different organs/systems in the earthworm. I also had some live worms out for them to look at.

We then dissected a sea star (starfish). Here’s a great video to watch if you don’t want to do the actual dissection, or to learn how to do it.

Here are some photos from my class:
sea star dissection

We also put some pieces under the microscope.

I found a nice handout online for the Lab: Starfish Dissection (www.pgsd.org/cms/lib07/PA01916597/Centricity/Domain/…/starfish%20dissection.do…) The previous link will download the document.  Holt Biology also had a sea star lab with a nice diagram.

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