Spring cleaning in your biology closet March 04 2020, 0 Comments
It’s that time of year when the urge to put things in order can strike. You may have a closet with a lot of biology materials that you want to evaluate. Here are my suggestions for things to throw out. You may not want to discard the whole material just because it has flawed content provided it is feasible to fix the problems.
In the animal kingdom materials, if you find anything that has the phylum Coelenterata, please remove that name or cover it. Biologists haven’t used it for more than 30 years. That phylum was split into two others when biologists discovered that it held two unrelated groups. The two lineages are called phylum Cnidaria (anemones, corals, and jellyfish) and phylum Ctenophora (comb jellies). It is likely that you can cover over “Coelenterata” and add the label “Cnidaria.” Just make sure that you don’t have comb jellies in with your cnidarians.
Another no-no for the animal kingdom is showing protozoa along with the animals. This goes back to the two-kingdom idea of classification, and biologists and biology textbooks haven’t grouped protozoans with animals in more than 40 years.
If you find a chart that is labeled “Non-Chordates,” change the title to “Invertebrates.” Maybe “non-Chordate” was useful in the past, but biologists use “invertebrate” far more often. I searched books on Amazon.com using “non-chordates,” and I got six titles, all published outside the US. I searched “invertebrates,” and got over 6000 titles. A non-chordate chart isn’t likely to show current information, so it is time to recycle it or at least recycle the images and add new text.
The relationships between the phyla of animals solidified about 15 years ago. In biology, classification has morphed into systematics, which all about relationships and shared common ancestry. The details of this would take several blogs so I will simply say that the arthropods are related to the nematodes, and the mollusks are related to the annelids. Arthropods were once grouped with annelids, but that is no longer considered valid. Can you add something to your animal kingdom chart that shows which phyla are closely related? See my book, Kingdoms of Life Connected, for help if your animal kingdom chart needs a redo. https://big-picture-science.myshopify.com/collections/frontpage/products/kingdoms-of-life-connected-second-edition. It is also available as an ebook (pdf).
Dig back into the cobwebs in the botany section of your closet. If your chart of the plant has club mosses separated from the fern clade – whisk ferns, horsetails, and ferns – you have a good representation of life’s diversity. The chart from InPrint for Children is a good example. https://big-picture-science.myshopify.com/collections/montessori-botany-materials/products/plant-kingdom-chart . Another mark of a current material – it should use the term “eudicots” instead of “dicots.” If your chart has phylum names, it is quite possible that many of the names are obsolete. Many botanists no longer use phyla or division names. Instead, they use lineage names, and sometimes a common name is all you need. I have a graduate level botany textbook that uses no phylum/division names.
If your plant kingdom chart has fungi or bacteria on it, the time has come to do some serious pruning. Those two have to go to their own charts. If the image of a fungus appears on a plant kingdom chart, that’s what children will remember even if you say that it doesn’t belong there. The fungus kingdom is a sister to the animal kingdom. In nature, fungi and plants are partners, but on classification charts, they shouldn’t hang around together.
If you have a Five Kingdoms chart, file it under the history of biology. It should NOT be the first thing children see as they study the diversity of life. The Tree of Life is the place to start.
How about your timeline of life? This is a difficult material to do well, and there are many bad attempts out there. Does your timeline show several red lines coming together (converging)? That’s the traditional style, but lineages do not converge (fuse together); they diverge (split apart). Maybe you could salvage the images and redo the timeline without the misleading lines. Check the dates for the fossils because there are several in the wrong place on the older timelines.
Does your timeline of life have photos of extant animals or plants in prehistoric times? This gives a very wrong impression. I’ve seen a timeline that had “First marsupial” and a picture of a kangaroo. This is just like saying “First eutherian (placental) mammal” and showing a picture of a horse. Both the kangaroo and the horse evolved within the last few million years. They are both adapted to live on grasslands and open shrub lands, where resources are spread out, and there is little cover from predators. Therefore both are good at moving quickly over long distances. Neither one of them belongs in the Mesozoic Era on a timeline of life. Mesozoic mammals were much smaller and less specialized.
Does your timeline have the five major extinctions? And does it have ice ages in the right places? The older charts used ice to symbolize all extinctions, although that wasn’t the cause in most of them. The five major extinctions come at the end of the Ordovician, Devonian, Permian, Triassic, and Cretaceous Periods. They are such important shapers of life that they are essential to a good timeline.
If all this correcting sounds like too much to do, remember that you are doing it for the children. They need current information and a foundation that they can use in their future studies. There is no point in giving them science “information” that they will never see outside a Montessori classroom.