What goes on a plant kingdom chart? December 27 2018, 0 Comments
Like its counterpart, the animal kingdom chart, all Montessori elementary classrooms need a plant kingdom chart. A current version of this chart will have the same elements as a traditional one, but the groups will not have the same labels or arrangement as they have had in decades past. DNA studies and phylogenetic systematics have changed the look of the plant kingdom, and our charts need to reflect this. It is hard to find a solid consensus among botanists on the “right” names, but that is no excuse for giving names that we know are obsolete.
I’ve listed my recommendations for contents of a current plant kingdom chart below. The names that I think are most important are in boldface type. The other names may also be useful. Ask yourself, “Will elementary children be able to use this name to find information that they can read and understand?” If you do a search using the name, do you find information that you can use and understand? If not, consider dropping the more technical name and using the common name for the lineage, the one I emphasize below. The terms on charts for children should be useful for understanding the diversity of life AND for finding further information.
Plant Kingdom (land plants, embryophytes)
Bryophytes (nonvascular plants)
Liverworts (Phylum Marchantiophyta)
Mosses (Phylum Bryophyta)
Hornworts (Phylum Anthoceratophyta)
Vascular Plants or Tracheophytes
Lycophytes or club mosses and relatives (Phylum Lycophyta)
Euphyllophytes, the “true-leaf” plants
Fern clade or Monilophytes (Class Polypodiopsida)
Whisk ferns and relatives
Equisetums or horsetails
Ferns or leptosporangiate ferns or true ferns
Seed plants or Spermatophytes
Cycads (Phylum Cycadophyta)
Ginkgo (Phylum Ginkgophyta)
Gnetophytes (Phylum Gnetophyta)
Conifers (Phylum Pinophyta)
Angiosperms or flowering plants (Phylum Magnoliophyta)
For a beginner’s chart, I start the plant kingdom with the land plants, the embryophytes. It is acceptable to add the green algae because they are closely related to embryophytes, but it is clearer if children learn about land plants first, and then add their relatives. Advanced students are ready for a chart of the Viridiplantae (green plants), which includes the green algae lineages and the land plants. It is important for children to understand that land plants and green algae share a common ancestor.
Don’t feel bad about leaving off phylum/division names. While the animal kingdom phyla have been rearranged by DNA studies, they have kept their names. Plant kingdom phyla or divisions, whichever you wish to call them, aren’t as useful anymore. In fact, I have a widely-used, advanced textbook for plant systematics that uses no phylum/division names at all. Instead, it simply uses names with no ranks for the major lineages, such as lycophytes, euphyllophytes, seed plants, and angiosperms. It still uses orders, families, genera, and species, the Linnaean ranks that botanists continue to use for plants.
There has been a big change that centers on the ferns. An older scheme had four phyla, Psilophyta, Lycophyta, Sphenophyta, and Pterophyta or Pteridophyta. These groups, often called “ferns and fern allies,” were considered more or less equal, but now we know that the lycophytes are a separate lineage from the other three. The fern clade, now considered by some to be a phylum, has three groups once considered separate phyla – the whisk ferns, horsetails, and the true ferns.
I see no reason to put notably out-of-date information on a plant kingdom chart. I especially encourage you to remove any images that are no longer considered plants. If you still have a mushroom on your plant kingdom chart, children are going to associate fungi with plants, even if you tell them that we know now that fungi are closely related to the animal kingdom and not at all close to plants. The visual impression that a chart gives to children is powerful, and it is important to get it as close to current as we can.
Change seems to come slowly in the general knowledge of plant systematics. I did an Internet search for plant kingdom charts and classification, and I found an amazing range of information from very old to current. Some websites even use the terms “cryptogams” and “phanerogams,” which came into use about 1860. Botanists haven’t used them in academic publications for at least 40 years. It is not that they are “wrong,” but they describe a superficial view that botanists had over a century ago. Our knowledge has grown, and there are better ways of expressing the differences among plant groups.
The flowering plants are currently divided into several lineages. I listed the main ones above, basal angiosperms, magnoliids, monocots, and eudicots. Botanists no longer use only the monocot and dicot subgroups, although these are still common in field guides and older publications. The flowering plants make up about 90% of the plant kingdom, and their orders have been defined in the last two or three decades using DNA studies. They deserve their own chart of orders and families.
My plant kingdom chart from my Tree of Life shows the lineages and their relationships. The plant kingdom chart from InPrint for Children gives children more practice with the categories.
Here are some quick ways to check the information on a plant kingdom chart for your classroom. If the chart shows a row of evenly spaced boxes, it isn’t giving children all the information they need. Bryophytes need to be grouped together and somehow spaced apart from the tracheophytes. Lycophytes should be separated from other spore-producing plants. If the club mosses, whisk ferns, true ferns, and horsetails are all grouped together and perhaps called “fern allies” or “pteridophytes,” that’s obsolete. There should be something to show that the club mosses are a different lineage from the three branches of the fern clade, and if possible, that ferns are more closely related to seed plants. If the term “dicots” or “dicotyledons” appears instead of “eudicots,” then that needs to change. Eudicots (“true dicots”) are the old dicots minus the magnoliids and the basal lineages such as water lilies.
The same criteria for illustrations on a kingdom chart apply to animals and plants. Can you see the important structural features that enable children to recognize the lineage? For example, can you see a fern’s fiddleheads or its sori? Can you see the sporophytes of the bryophyte lineages? Sporophytes need to be visible and described in the text. The reproductive structures and foliage of the gymnosperms help children tell the difference between those lineages. Flower illustrations should clearly show stamens and pistils. Consider showing a fruit as well because fruits are unique to the flowering plants.
In the text for the chart, give children a range of examples whenever this is possible. Children, like much of our society, are less likely to be familiar with plants than they are with animals. They may be surprised to learn that grasses, maples, and oak trees are flowering plants.
Enjoy opening children’s eyes to the diversity of plants! For more information about the plant kingdom and its members, see my book, Kingdoms of Life Connected.
The New Edition of Kingdoms of Life Connected is here! October 30 2016, 0 Comments
The second edition of my book, Kingdoms of Life Connected: A Teacher’s Guide to the Tree of Life, is available now. I wrote the first edition in 2008, and it was already time for an update this year. New information keeps coming in all fields of science. This leads to gradually evolving ideas, but change has been exceptionally rapid in the field of systematics, the study of the diversity of life.
The flood of DNA information continues, and we must bear that in mind in our presentations. It would be better to state that the story you tell is based on the evidence scientists have gathered for now. In the future, there could be adjustments. This doesn’t mean that all the information about the Tree of Life will change. Instead there will be small alterations. The potential for change certainly doesn’t excuse the presentation of obsolete classifications as anything other than history.
One of the hardest tasks for my book revision was finding up-to-date children’s books about the diversity of life. I had to leave many older, but valuable, books on the resource lists. At least it is easier to find out-of-print books now than it was a decade ago. I also found that publishers have reprinted some valuable older books. They include Peter Loewer’s Pond Water Zoo: An Introduction to Microscopic Life. Jean Jenkins illustrated this book in black and white, and it has attractive, clear drawings of many protists, bacteria, and microscopic animals, along with text that upper elementary children can read. You will have to warn your children that the classification scheme presented, the Five Kingdoms, is obsolete, but the information about the groups of organisms is still quite good.
A forty-year-old book by Alvin and Virginia Silverstein, Metamorphosis: Nature’s Magical Transformations, has been reprinted by Dover Books. It has a chapter on sea squirts that shows the tadpole-like larval stage and tells about the life cycle of these chordates. I haven’t found another children’s book that tells this story. The black and white illustrations show how old the book is, but there didn’t seem to be a good alternative.
I know the pain of having to purchase a new edition of a reference book. My favorite biology textbook cost nearly $200, and I see the new edition, just published this month, is priced at $244. Yikes, that’s hard on the budget. If you own the first edition of Kingdoms of Life Connected, you will be able to purchase the ebook version – the pdf file – of the book at a reduced price. Please email info (at) bigpicturescience (dot) biz for information about how to do this.