Zoology 6-9
Have you ever observed a wiggling worm around after a rainy day as a child? Children are always fascinated and become observant when seeing earthworms make their way through rough terrains. But, not all worms are created equally. They may share similar characteristics but are quite different if we look at them closely. Worms can be classified into 3 major phyla: platyhelminth (flatworm), nematode (roundworm), and annelid (segmented worm.) All of these animals are invertebrates, meaning that they do not have a spinal cord. They are also bilateral symmetrical organisms; their bodies are slender with two thin extremities, the head, and the tail. Worms consist of tissues that form organs and organ systems. Even though worms are simple living organisms, they possess a brain connected to a nerve cord that allows them to sense and move. Some worms are extremely beneficial for the environment in which they live; some others are mostly parasites that rely on a host to survive.
Based on the Montessori zoology curriculum, we have created a complete series of materials on invertebrate animals, which includes the internal and external parts of a platyhelminth, a nematode, and an annelid. Just as we teach children “shapes of a leaf” in botany, we purposefully developed our materials based on the phylum of these invertebrates, rather than on specific animals. This way, children’s minds remain flexible. They have an opportunity to expand on each phylum by researching a variety of animals. In this post, we would like to tell you more about platyhelminths, nematodes, and annelids.
Materials
- Parts of a Platyhelminth – Puzzle and Nomenclature Cards Ages 3-6 & 6-9
- Parts of a Nematode – Puzzle and Nomenclature Cards Ages 3-6 & 6-9
- Parts of an Annelid – Puzzle and Nomenclature Cards Age 3-6 & 6-9
- Additional – Animal Kingdom – Invertebrates
How to Use the Materials
It is always important that children be in contact with a real-life specimen before learning about it. You can find Platyhelminthes in freshwaters such as ponds or streams, under rocks, plants, or debris since they avoid direct sunlight. Earthworms can be found abundantly in damp soil or near moist places such as under a log, or a rock as well. You may find nematodes by digging in the soil, but pay close attention as these roundworms can be minuscule. If no real-life specimens are available, it is possible to use a model or a picture as well.
Parts of an Annelid
Gather a group of children, indoors or outdoors to observe an annelid. Ask children what they notice. Encourage discussion. You can explain that what they know as an earthworm can also be named “annelid” as it belongs to the Annelid Phylum in the Animal Kingdom. You can mention that the annelid has a segmented body, we can observe its clitellum (ring located in the middle of the body.) Ask children about the worm’s body movements. The annelid uses muscles and chaetae (bristles) to move quickly. Explain that this segmented worm may be simple, but they have five hearts, a digestive system, and a closed circulatory system with blood vessels, which is considered sophisticated for a worm! You can talk about its habitat, diet, and its contributions to its environment. Handle the worm(s) with a lot of care. Following this presentation, you can introduce the Parts of an Annelid Nomenclature Cards so that children become acquainted with the different parts of an annelid. On the same day or another day, you can present the Parts of an Annelid Puzzle with arrows and a control chart. Parts of an Annelid Nomenclature Cards set contain reproducible materials such as a booklet and a backline master, which can be copied in advance for children to complete.
Parts of a Nematode
Just as you presented a real-life specimen (model/picture) of an annelid, proceed the same way when introducing a nematode. Nematodes can be so tiny that they can only be seen under a microscope and some can grow up to 40 feet long. Different species of nematodes feed on different things such as bacteria, fungi, other animals, and even other nematodes. The nematode has a particular attack mechanism called ‘the retractable piercing device.’ It is located on the mouth end side and is used to pierce through prey and to protect from predators. The nematode’s body is not segmented. It is comprised of organs such as nerve rings, an intestine, and reproductive organs. Nematodes are usually prolific parasites that live at the expense of a host.
Parts of a Platyhelminth
Don’t be afraid of pronouncing it! You will get used to it: plat-ee-hel-MIN-th. The platyhelminth, unlike an annelid and a nematode, has a flat body with no body cavity (acoelomates), thus its name ‘flatworm.’ The platyhelminth is lacking a circulatory and respiratory system but does possess an execratory system with no anus. It regurgitates body waste through the mouth orifice. The brain of the platyhelminth consists of tissue with lateral longitudinal nerve cords, which are connected by transverse nerves. 75-80% of limnic, marine, or terrestrial species of platyhelminths are parasites!
Following all three introductions of these different types of worms, you can leave the materials together in the zoology area for children to make meaningful comparisons and refine their understanding of the world around them. The reproducible materials found in the Nomenclature Cards sets make excellent supplemental materials for children. They can focus on each part of the animal and truly understand its characteristics. Children can also keep their work in a portfolio, which serves to reactivate knowledge when revisited.
So who would think worms are different from one another? Yet, they are. I hope you can share this knowledge with children! Knowing more about wiggly worms will enhance children’s nature walks, and might help them with orticultural skills!
*This post is meant to provide educational guidance, and has been made possible by Alison’s Montessori which provided the materials at no cost. Alison’s Montessori is known for creating authentic Montessori materials and support materials that are aligned with the Montessori curriculum.
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Montessori Second Plane of Development 