To most of us, one earthworm resembles another. Although earthworms do have common characteristics, species differ widely in their size, skin colour and in the roles they play in the soil ecosystem.
Earthworms are found in all but the driest and coldest land areas in the world. There are about 4000 species worldwide. In New Zealand, we have over 200 known species. Most of our earthworms are endemic (found nowhere else on Earth). However, the earthworms we are most likely to encounter on rainy footpaths or in garden or pasture soils are introduced species.
Our earthworm resources move beyond the tiger worm and composting food scraps to delve more deeply into how scientists conduct investigations regarding earthworms and agriculture. We explore living things, using earthworms as an example, and look at their adaptations for life in the soil. We also learn about one of our unusual native earthworms. Our interactives, videos and teaching activities will give students a new perspective on the ‘lowly’ worm.
We’ve seen earthworms struggling across footpaths on rainy winter mornings or ducking for cover when we turn the compost, but what do most of us really know about them? A quick library and internet search provided little more than basic anatomy and composting hints.
We were very fortunate to meet Dr Nicole Schon (AgResearch) and Dr Trish Fraser (Plant & Food). Both are actively researching the effects of earthworms in agricultural ecosystems. It did not take long to realise that earthworms are actually more complex and interesting than we’d first thought!
The science behind earthworms
These are the big science ideas:
- Scientific investigations can run for a few months to a few decades. They can be small and tightly controlled or much larger studies involving real-world conditions.
- Observation is crucial to a scientist’s work, and observation comes in many forms.
- The characteristics of living things and what makes an earthworm an animal.
- Earthworms live within different niches in the soil and have physical adaptations to suit each niche.
- The earthworm’s role in the ecosystem is much more than making compost.
- New Zealand has both native and introduced earthworm species.
In addition, these articles investigate the regulations and ethics involved with keeping earthworms in the classroom. We also look at one of history’s most famous scientists, Charles Darwin, and his fascination, appreciation and observations of the lowly worm.
The role of observation in science
Observation became a key part. Our first experience of truly observing earthworms was in Nicole’s lab. She had a number of species, and we were able to see them side by side and watch their movements. Nicole pointed out differences in their appearances and showed us the native O. multiporus, a large bioluminescent specimen. Our observation skills were further honed when Ross Gray posted us 10 different species of earthworms. (They lived in Angela’s fridge until the video crew arrived!)
Next to observe the earthworms was the Worm Team – a year 4 class in charge of the compost system at a local primary school. The students spent a morning learning about earthworm characteristics and observing how the various species looked and moved. Their comments and questions formed the basis of our teaching and learning activities. The earthworms were then set free in Angela’s garden and patch of backyard bush. We still see each other on occasion!
Teaching and learning: observing earthworms in the 21st century
The Science Learning Hub is all about innovative and media-rich learning opportunities. We wondered how students might best learn about the different physical and ecological characteristics amongst earthworm species. The answer? Wormface – social networking for earthworms! In this activity, students develop a profile for an earthworm species. To do this, they must research its scientific and common names, its physical characteristics and the role it plays in the soil ecosystem. Students record this information in a rather creative and novel manner.
Several videos allow students to observe earthworms in a vicarious manner, so if teachers find it difficult to obtain earthworms or are hesitant to have these wonderful earth workers in their classrooms, students don’t have to miss out.