Banishing the Kingdoms November 23 2023, 1 Comment

What’s New in the Third Edition of Kingdoms of Life Connected? January 12 2023, 1 Comment

Last fall, I completed the third edition of my book, Kingdoms of Life Connected: A Teachers’ Guide to the Tree of Life. This came only six years after the second edition, which in turn came eight years after the first edition. “Why all this change?” you may ask.

I found that updates were needed because of changes in biologists’ view of the diversity of life. The data about how organisms are related continue to pour in, and because of this, the details of lineages and relationships change. You may be tempted to wait until the field stabilizes and stick with older ideas. Children, however, need a useful view of the diversity of life, even if it will be somewhat amended later. They cannot build on a foundation that is clearly obsolete. Specifically, it is no longer useful to present children with Five or Six Kingdoms, and those charts need to go in your history-of-science file.  

I updated Kingdoms of Life Connected from cover to cover. I redid the lists of learning resources – books and websites; I purged links that no longer worked and added new ones. Publishers and authors have brought forth valuable new books in recent years, and I added titles to the lists while retaining older but useful books. I revised all the text, including the activities and lesson suggestions. I fact-checked the information to make sure it was as up to date as I could make it.

There is one especially important addition, a new lesson for introducing to the Tree of Life chart to beginning elementary children. This lesson gives older children important concepts as well, particularly if they have not yet had this overview. The introductory lesson leads children to the idea that all life shared a common ancestor and is connected. It shows them the relationships between the major branches of life. For example, they learn that the animals and fungi are sister lineages and that plants are only distantly related to fungi.

I’ll give a brief summary of some of the changes below. For more information, see the book, which is available at https://big-picture-science.myshopify.com/collections/biology/products/kingdoms-of-life-connected-third-edition (printed version). The ebook (pdf) is at https://big-picture-science.myshopify.com/collections/biology/products/kingdoms-of-life-connected-third-edition-ebook.

There are no big changes in the prokaryotes. I have kept a very basic approach because it takes extensive knowledge of biochemistry to understand the many branches of bacteria and archaea. Introductory college biology texts present a few basic lineages, and I felt that this approach would be good for children as well.  

In the protists, I rearranged the Excavata lineage on the Tree of Life chart. Now, the euglenazoa and kinetoplastids are sister lineages and the metamonads are the first branch. I expect that Excavata will be split apart and redone in the future. It probably won’t be a eukaryotic supergroup, but studies continue to confirm the other supergroups – Archaeplastida, SAR, and Amorphea.

Scientific terminology evolves, and I was happy to see a complicated name go away. The branch of the stramenopiles and alveolates was previously called Chromalveolata, but that term has fallen out of favor. It originally described a lineage that included two branches I didn’t show, the cryptophytes and haptophytes; these are now placed elsewhere on the Tree of Life. The branch of the stramenopiles and alveolates may get a new name, but it seems best to leave that branch blank for now.  

The fungi were the major branch that changed the most. The former Zygomycota lineage is now divided into two main lineages, the Mucoromycota and the Zoopagomycota. On my Tree of Life chart, I show the larger one, Murcoromycota. Its branches include the pin molds or Mucoromycotina (black bread mold, for example) and the arbuscular mycorrhiza fungi or Glomeromycotina (AM fungi). The AM fungi were previously placed on their own branch, but they have been added back to Mucoromycota. I didn’t add the Zoopagomycota to the Tree of Life chart, but if you have children who are interested in learning more, Fungarium by Katie Scott and Ester Gaya, is a good book for launching their explorations.

In the animal kingdom, studies have clarified some relationships in the protostome branch. You can give children the term “Spiralia” for the lineage previously called Lophotrochozoa. The whole branch is called Spiralia; “Lophotrochozoa” still refers to the mollusks and annelids. It is another of the situations where it is useful to know an older and newer term. “Lophotrochozoa” has been used for the Spiralia branch for about 20 years, and it appears in a number of websites. I recommend looking to the future and using “Spiralia” primarily. It is certainly easier to say and spell.

In the plant kingdom, studies have resolved several questions about the bryophytes. They are a single branch of life, a monophyletic lineage. The first branch was recently determined to be the hornworts. The mosses and liverworts are sister lineages. The older story was that the liverworts were the first branch because they do not have stomata. It appears that their ancestors lost their stomata rather than never having them.

The virus chapter now has suggestions for making a model of a coronavirus. I published this chapter as a stand-alone pdf in 2020. Note that if you have the third edition of Kingdoms of Life Connected, you already have the content of “What Is a Virus?”.

It is easy to become overwhelmed by all the names and branches of life. I recommend that you concentrate on the larger branches on the Tree of Life and continue to other branches as children (and you) learn about these and are interested in pursuing more. For in-depth studies at the elementary level, I recommend the digging further into the animal and plant kingdoms.

Start with the big overview of the Tree of Life. After that, my learning material, Sorting Branches on the Tree of Life: Vertebrates and Plants, is a good place to go. It is available as a pdf that you can print https://big-picture-science.myshopify.com/collections/biology/products/sorting-branches-on-the-tree-of-life-vertebrates-and-plants or as a printed material https://big-picture-science.myshopify.com/collections/biology/products/copy-of-sorting-branches-on-the-tree-of-life-vertebrates-and-plants-file-for-printing.  

Enjoy your explorations of the Tree of Life!  

The Gorilla in the Montessori Room July 15 2022, 2 Comments

What is this about a gorilla in the Montessori room? Is it a radical new classroom pet?

No, it is a symbol of an ongoing problem that is being ignored for many reasons – it is difficult, uncomfortable, and so big that it will take considerable effort to deal with it. Here is why I think there is a “gorilla” in Montessori classrooms.

Maria Montessori designed her brilliant elementary framework around five great lessons, and she constructed it with her perspective as an early 20^th century European. Her understanding that children need spiritual nourishment, not just facts, guides us today. Her stories are tied into the science content she felt children should have. She gave them real knowledge, not a watered-down version, along with inspiration to learn more.

The inspiration and spiritual nourishment are still wonderful, but there is a problem with the content of those stories and the lessons that come from it. She used the state-of-the-art information for her time in the stories, and many classrooms still do that – they use the state-of-the-art biology from the mid-20^th century. This leaves children woefully out of touch with today’s view of life science.

Biology has come a long way since the mid-20^th century. Not only are two, five, or six kingdoms obsolete, but the whole idea of kingdoms is not what it once was. If you still use five or six kingdoms as your main lesson on the diversity of life, it is time to move those materials to the history of biology and move on. The Tree of Life provides the framework now, and the three kingdoms (fungus, animal, and plant) that are still valid are not the organizing framework for the diversity of life. Instead, they are major branches among many others on the Tree of Life. Biologists have extended classification to include the relationships between all kinds of life. Shared common ancestry drives classification, not just physical appearance.  

For an example, see the website for animals, The Shape of Life: The Story of the Animal Kingdom (https://www.shapeoflife.org/). It has a tree of life that gives the derived traits for the lineages. You can download the pdf from https://www.shapeoflife.org/news/resource/2016/10/18/tree-life and print it. This branching diagram is not for beginners, but it will help you see how the diversity of life is shown scientifically.

This website also has an artist’s Tree of Life for animals, and I think children would enjoy poring over it. It is by Ray Troll; the pdf is available at https://www.shapeoflife.org/news/featured-article/2018/02/26/we%E2%80%99ve-got-your-tree-life-right-here. Even though it is an artist’s interpretation and shows little of the other branches of life, it has valid branches for animals.

There has been such a revolution in biologists’ ideas about the diversity of life that it has required college professors to be flexible and ready to change. Some revise their course content on a yearly basis. DNA data has been a big part of the change, and biologists continue to acquire new data. The rapid change doesn’t mean that it is OK to stick with old ideas until the field settles down. It means that children need the new framework and new ideas about how biologists see life’s variety. They don’t need to spend time learning a system they will set aside in further studies.

Back to that “gorilla.” I see that inadequate movement toward new ideas is common in Montessori teacher education programs. The extent of change in biology means that everyone needs to learn current biology ideas, including teacher educators and teachers with all levels of experience. It calls for relevant conference presentations and professional development courses. It means that teachers can’t simply change a few terms and keep teaching the old framework.

Certainly, there has been progress in updating biology for Montessori schools. Cynthia Brunold-Conesa’s album, Life Science Lessons for Montessori Elementary Classrooms, has a totally new structure and current ideas. You can find it at https://georgeconesa.wixsite.com/lifesciencemont. 

For more than two decades, I have been working to bring updated materials with current ideas to Montessorians. My recent video course, Life Science Literacy for Elementary Teachers, is available through Trillium Montessori at https://courses.trilliummontessori.org/p/life-science-literacy. I have revised my books and card sets multiple times, and I continue to do so each time I reprint an item. The websites change, the classifications change, and even the terminology evolves.  

Montessori classrooms help children acquire knowledge. In biology, will it be useful knowledge, or will they have to relearn the subject later? It depends on whether Montessori leaders do something about that gorilla in the room. 

Priscilla Spears, July 2022 

Why Montessorians need a new biology album July 28 2021, 0 Comments

Sorting Branches on the Tree of Life August 07 2020, 1 Comment

Studies of the diversity of life are a pillar of life science at elementary level. In the past, Montessori classrooms used charts that show Linnaean classification – Kingdom, Phylum, Class, etc. Those charts are no longer very useful except in studies of the history of science. Instead, children need an introduction to the Tree of Life, which they can get via a branching diagram aka family tree, evolutionary tree, phylogenetic diagram, or phylogeny. If you need a Tree of Life diagram, you can download one for free at my website.

In early childhood, children sort pictures under labels, beginning with living vs. nonliving, animal vs. plant, and invertebrate vs. vertebrate, for example. Later, they sort pictures under more categories such as classes of vertebrates or phyla of invertebrates. The activity in my new material, Sorting Branches on the Tree of Life, will look somewhat familiar to children, but it has enough differences to make it challenging and interesting.

As Montessori classrooms adapt to the changing world of academic knowledge, one of the first things will be to help children learn the main branches on the Tree of Life. They need an introduction to the Tree of Life to get an overview, and then they are ready to start studying the main branches. Note that I use the terms “clade,” “lineage,” and “branch” to mean more or less the same thing – an ancestor and all of its descendants.

A challenge of Tree of Life classification is that the big branches have little branches, and the branches are not ranked (aren’t a phylum, class, etc). One simply has to know that the vertebrates are a branch of the chordates, for example. It really isn’t as hard as it sounds. Sorting Branches on the Tree of Life will help children and adults learn the main branches as they sort photos of organisms under a set of heading labels. When children have completed the diagrams, they will be able to see that the organisms belong to a number of clades. They will also be more prepared to use phylogenies (branching diagrams) that show the main branches. Older ones may even want to try their hand at drawing a phylogeny based on a diagram they have completed.  

Sorting Branches on the Tree of Life covers the vertebrates and the plants. It has a series of lessons, each of which builds on the last to help children learn the clades (branches, lineages). The lessons use images of extant animals (with one exception) and plants, but they tie into some of the history of the clades as well. One really can’t teach about the diversity of life without giving information about the origin of the branches of life.

I’ll start with descriptions of the lessons for the vertebrates in this article and leave the plants for another day. The first lesson shows the earliest branching of the vertebrates, which produced the jawless fish and the vertebrates with jaws. The latter clade, called the gnathostomes, has two branches, the cartilaginous fishes and the bony vertebrates. I have called the second branch the bony vertebrates instead of the bony fishes because it holds more than just fish. It is actually our branch as well.

The bony vertebrates have two branches, the ray-finned fish and the lobe-fins. The latter includes the coelacanth and the lungfish, as well as the tetrapods, the animals with four limbs. I used a picture of a lion to represent the tetrapods so that children could see that ALL the tetrapods belong to that lineage, not just the amphibian-like, first ones to evolve.

The second lesson shows the branches of the tetrapods, and its diagram shows that birds are a branch of the reptiles.

Reptiles, birds, mammals, and eutherian mammals each have another lesson with a diagram. The reptile and mammal lessons come after children have had the tetrapod lesson. The reptile lesson shows that this branch of life divides into the lepidosaurs (“scaly lizards”) and the archosaurs (“ruling lizards”). For the latter, the branches are the crocodilians (crocodiles, alligators, and relatives) and the dinosaurs. The pictures under the dinosaur label are a non-avian dinosaur and an avian dinosaur – a chicken. Yes, the birds are really dinosaurs, and they should be placed under the archosaur label.

Don’t panic at the idea of birds being a branch of the reptiles. We can still teach about those two branches of life separately. The traditional reptile lessons usually give the characteristics of the squamate reptiles – lizards and snakes – or of turtles, which are a world of their own, a sister branch to the archosaurs. Lessons can emphasize the traits that birds and crocodilians share. Studies of birds can note their reptile-like traits such as scaly skin on their legs.  

The mammal diagram shows the first two branches as the monotremes and the therians. This omits a lot of mammal history, but the point of these lessons is not the whole history of the organisms. It is about the branches of the currently living ones. The therians are the marsupials and the eutherian mammals, aka placental animals. When you have finished the lesson on the eutherian mammals, children can go back through and make a list of their own branches of life.

I produced this material this spring, and children in a Montessori classroom got to see a prototype just before the schools closed because of the pandemic. The teacher reported that they were very interested in the material, partly because it doesn’t look like all their other materials. By elementary age, children are ready for variety and challenge. Sorting Branches on the Tree of Life supplies both.

Why are updates so hard? October 28 2019, 0 Comments

How do you divide the eukaryotes? September 19 2019, 0 Comments

If I asked you how you would divide the eukaryotes into groups, what would you say? Many people would say protists, fungi, animals, and plants. This is the idea presented in Five (or Six) Kingdoms classification. There is a more enlightening way to divide the eukaryotes, one that students currently see in introductory college courses.

The DNA revolution and the development of systematics rather than plain classification have given us a new view. Systematics includes the relationships between taxonomic categories instead of listing them with no information about their shared ancestors. It is a young science that has produced many changes and will likely produce many more.

This is not to say that we don’t have useable information right now. The largest categories of eukaryotes have been defined, and they are called the eukaryotic supergroups. There are four of them presently, and so the eukaryotes can be divided into four groups. Here’s an introduction to the archaeplastida, SAR, excavata, and unikonts aka Amorphea.

Archaeplastida is the lineage that acquired the first chloroplast. Its name means “ancient plastids.” A plastid is a type of organelle in a eukaryotic cell, and the category includes the chloroplast, whose name means “green body.” The archaeplastida lineage includes red algae and green algae, along with the embryophytes or land plants, which evolved from a green alga. This lineage is the only one that incorporated an ancient cyanobacterium into its cells. The origin of the chloroplasts in other lineages is a more complicated story.

The SAR lineage is named for the three main branches within it, stramenopiles, alveolates, and rhizarians. These lineages were defined independently and then researchers gathered enough evidence to conclude that they share a common ancestor. The stramenopiles (aka chromists or heterokonts) include brown algae, golden algae, diatoms, and water molds. Alveolates include dinoflagellates, apicomplexans (parasites such as malaria), and ciliates. The rhizarians include foraminiferans and radiolarians, single cell organisms that build amazing outer shells called tests.

And where did these branches of life get their chloroplasts? It seems that chloroplasts are NOT easy to acquire. Apparently, it is easier to take one from another cell than to acquire one by eating a cyanobacterium. An ancestor of the stramenopiles and alveolates probably ate a red alga and kept its chloroplasts. Euglenas, which we meet below, got their chloroplasts from a green alga.

The third eukaryotic supergroup is the excavata, also called the excavates, but I see potential for confusion between the word as a noun vs. a verb. The lineage is named for a groove that looks like it has been excavated from the cells of some members. The excavata include the euglenas, which are free-living, and the trypanosomes, which are parasites. Other members of this group include the parasite Giardia and organisms that live in the guts of termites and help them break down cellulose. These have reduced mitochondria, so small that they were first described as lacking mitochondria.

I know you have been waiting for the last of the four supergroups, our own lineage, the unikonts (“single flagellum”) also known as the Amorphea (“having no form”). “Wait a minute,” you may be thinking, “we definitely have form.” The amoebas that belong to this lineage do not, however. The Amoebozoa lineage includes most of the slime molds or social amoebas as well as the single cell ones. Some of the latter build hard coverings (tests) for themselves. The other members of the unikonts are the fungus kingdom and the animal kingdom, which are sister kingdoms, having shared a common ancestor right before they branched off. There are other single cell organisms that are related to animals and fungi as well.

As you can see, the old protist kingdom had many different lineages of life shoe-horned into it, and the kingdoms that developed from its members were chopped off and boxed separately from it in the Five (or Six) Kingdoms scheme.

Why should you or your children learn about the supergroups of eukaryotes? It gives you a richer view of life and one that your children will see in their future studies. Will the names stay the same? Maybe, or maybe not, but these are the names in current college biology books, and it is worthwhile to learn about them and their members now.  

Enjoy your explorations of the living world!

Priscilla 

How do you know it's right? Resources for fact-checking October 21 2018, 0 Comments

Why is the horse the example of a mammal? January 30 2018, 1 Comment

Certain materials are “classic” in Montessori classrooms. The external parts of the vertebrate animals are one of those essential materials. This set traditionally has a horse as the example of a mammal, and almost all commercially available card sets for study of the vertebrates uses the horse.

My question is “why?” Unless we try to understand Maria Montessori’s purpose in the design of her materials, we can easily get caught in a web of tradition that keeps us from serving children’s learning needs to the best of our ability.

Here is my best guess on the horse as the mammal example. The horse was present in the lives of children all over the world until about 1920. It didn’t matter if they lived in a city or on a farm. When Maria Montessori first created her materials, the mammal that most children would see in their everyday lives was a horse. That has changed for most children. The horse is still used for transportation in some rural areas, but this animal is now more likely to be seen in a hobby or leisure situation. Most children in the United States do not see a live horse with any regularity.

What mammals do children see today? Dogs and cats would likely top the list. Classroom pets like gerbils, guinea pigs, or hamsters are common enough. Why don’t we use one of these for the example mammal? Children are more likely to be interested in learning about an animal they can experience, and learning about the care of that animal may also be very relevant to them.

Should we get rid of the “Parts of a Horse” cards? Probably not. There is nothing to keep you from having additional examples after you study the first one. Some children do see horses regularly and will be very interested in learning their parts.  Others could have their horizons expanded by seeing additional examples.

What about the other vertebrate examples? The frog as an amphibian is about as good an example as a newt or salamander. The latter two are harder to observe in nature, but they can be kept in the classroom, probably with fewer problems than keeping a frog. It depends on the frog. Some can be escape artists – voice of experience here.

The turtle probably became the reptile of choice because it is less intimidating than a snake or a lizard, but a lizard gives a better look at the basic reptile body. Turtles are quite derived – they have changed a lot from their ancestors. They still have the scaly skin and lay eggs, so they work.

At some point, the crocodilians (crocodiles, alligators, caimans) need their own category. They are more closely related to birds than they are to the squamates (snakes and lizards). Both crocodilians and birds belong to the archosaur branch of the reptiles. Now that this is known, even children’s books point out the similarities. Both birds and crocodilians make nests, vocalize, and care for their young. They both have four-chambered hearts as well.

These two are closer cousins than either is to a lizard.

Using a perching bird for the example of the feathered vertebrates works well. It is worth asking, however, what birds children see. Maybe they see chickens on the school grounds. Maybe it is song birds that come to a feeder. Maybe it is a pigeon in the city. Maybe it is caged bird in the classroom. Going back to a real bird is an important step to make learning the parts into living knowledge.

Finally, the whole collection of vertebrates should be called the groups of vertebrates, NOT the classes of vertebrates. Biologists haven’t placed fishes into a single class since about 1850. The former classes were jawless fishes, cartilaginous fishes, ray-finned fishes, and lobe-finned fishes. That’s much more than children need at the beginning of their studies. The classroom fish tank can house valuable examples of ray-finned fishes, and that’s a great launching point. After all, ray-finned fishes are more than 99% of all fishes.

You can look that fish in the eye and say to it, “You and I shared a common ancestor, back in the beginning of the Paleozoic Era.” You can tell the amphibian that you shared a common ancestor with it back in the Devonian Period. Not long (geologically speaking) after that in the Carboniferous Period you shared a common ancestor with birds and reptiles, the other animals that reproduce on dry land, which are known as the amniotes.

It’s all in the ancestors and the great evolutionary journey. Enjoy the trip.

Help with studies of flowering plant families June 01 2017, 1 Comment

For many years, I have promoted the idea of structuring botany around the flowering plant families. It’s a practical way of addressing the diversity of the angiosperms, and it is knowledge that works in many places and at many levels. For instance, organic gardeners need to know the families of vegetables so that they can do the proper crop rotation and fertilizing. Plant identification is much easier if one can determine the family. Flowers in the same family share certain features, so it is quite possible to recognize the family even if you have never seen that species before.

To help you with your botany studies, I’ve just revised and expanded my PowerPoint slides on flowering plant families. This file is a pdf that can be printed to make letter-sized posters of 20 flowering plant families. The slides include text that describes the features of the flowers, and they show photos of family members. To round out this material, I’ve added a representative photo of 48 other families or subfamilies from all branches of the angiosperms. 

Perhaps you would like to do a Tree of Life diagram for the flowering plants. There is a good one in the book, Botanicum by Katie Scott and Kathy Willis. It is part of the Welcome to the Museum series from Big Picture Press (no relation to Big Picture Science), and it was published in 2016. The branches are correct on the diagram (pages 2 and 3), but they have just one example for each branch, and the orders are not stated. The example represents a whole order, which leaves out a lot. For example, the rose order, Rosales, is represented by a mulberry leaf. Mulberries and figs belong to family Moraceae, which is in the rose order, along with rose, elm, buckthorn, hemp, and nettle families. On the other hand, the diagram fits on two pages. It have to be much larger to be more comprehensive. All-in-all, the book is delightful and will provide lots of fun browsing. You will have to tell children that the page on fungi is a holdover from earlier definitions of botany.

The photos of families from my newly revised Flowering Plant Families Slides can be used to create a Tree of Life that has many orders. It gives a broader look at the families than its predecessor, and it is still centered on the families of North America. There are over 400 families of angiosperms worldwide. You don’t need to worry about being anywhere near comprehensive when you introduce children to flower families. Select the main ones for which you have examples from your school landscape, in areas near the school, or as cut flowers. If you or your children want to see the full list, go to the Wikipedia article on APG IV system (Angiosperm Phylogeny Group IV).   

I’m not the only one that advocates structuring botany studies around flowering plant families. Thomas Elpel has written a highly successful book called Botany in a Day: The Pattern Method of Plant Identification. It is further described as “An Herbal Field Guide to Plant Families of North America.”  This book is in its sixth edition. It has color drawings as well as black and white ones, and these could be useful in classrooms. I have not recommended placing this book in the elementary classroom, however, because it includes many food and medicinal uses for wild plants. I do not want to encourage children to eat wild plants or use them as medicine.

Botany in a Day is available from Mountain Press Publishing in Missoula, Montana, which also carries Elpel’s flower family book for children, Shanleya’s Quest. This book is a great one for elementary classrooms, and I strongly recommend it.

Enjoy exploring and identifying the flowers!