From tadpoles turning into frogs to caterpillars transforming into butterflies, metamorphosis is one of natureโs most incredible processes. Understanding metamorphosis helps students see how organisms grow, adapt, and survive in their environments. Whether you’re exploring amphibians, insects, or life cycles in general, this fascinating transformation is a perfect way to bring nature and science to life in your classroom.
๐A Note for Teachers ๐: If youโre an educator planning to teach metamorphosis and animal life cycles in your classroom, great learning resources are key to deepening understanding! You can find materials for teaching metamorphosis in my Amphibians Unit and Insects Unit, as well as my Aquatic Macroinvertebrates Unit – plus tons of other materials and activities for these fun topics! (And youโll support this blog with your purchase! โค๏ธ)
What is Metamorphosis?
Metamorphosis is a process where an animalโs body changes form at different stages of its life cycle. Many insects and amphibians go through metamorphosis, developing in two or more distinct stages, like a legless tadpole becoming a frog or a wingless caterpillar transforming into a butterfly.
In contrast, reptiles, birds, and mammals (including humans) do not undergo metamorphosis. Consider human babiesโas we grow, we get bigger and taller, but our basic body shape stays the same. We donโt develop wings, extra limbs, or entirely new body parts like a butterfly or frog.
Amphibians and Metamorphosis
The word โamphibianโ means โdouble lifeโ, referring to how most amphibians begin their lives in water before transitioning to land. This transformation happens through metamorphosis. Take frogs, for example โ tadpoles swim using their tails and breathe underwater through gills. During metamorphosis, they grow limbs and lungs, allowing them to live on land as adults. Just like tadpoles transform into frogs, most salamanders start as aquatic, legless larvae before developing their adult forms.
Most amphibians go through metamorphosis, but there are a few exceptions. Some species of caecilians, a group of legless amphibians, develop differently and donโt go through metamorphosis the way frogs and salamanders do.
Insects and Metamorphosis
Amphibians are not the only animals that go through metamorphosis. Many (though not all) insects go through metamorphosis too. One of the most classic examples is a butterfly. A butterfly starts life as a wingless larva called a caterpillar, a life stage in which the main goal is to eat and grow! After some time, the caterpillar stops munching and forms a chrysalis. During this stage, called the pupa stage, it doesn’t eat, but continues to develop. Finally, the winged butterfly emerges from its chrysalis – now it is an adult.
However, butterflies are far from the only insect to go through metamorphosis. Caddisflies, ladybugs, beetles, and ants are a few other examples of insects whose lives take place in three stages: larva, pupa, and adult. Insects like these with three distinct life stages go through what scientists call “complete metamorphosis“. In contrast, some other insects, like dragonflies and mayflies, go through “incomplete metamorphosis“. These insects only have two life stages: nymph and adult.
Why Metamorphosis?
Why change forms at all? Metamorphosis helps animals use different habitats and resources at each stage of life. For example, tadpoles live in aquatic habitats like ponds and eat plants, so they have gills, a small mouth, and a tail for swimming. But as they grow into adult frogs that hunt insects on land, they develop lungs, strong legs, and a wide mouth with a sticky tongue for catching prey.
Similarly, caddisflies, mayflies, dragonflies, and other aquatic insects begin their lives in water as larvae or nymphs. This allows them to feed on aquatic plant matter, detritus, or small organisms found in habitats at the bottoms of streams and ponds. As they go through metamorphosis, these insects emerge from the surface of the water as winged adults. After this, they use their wings to take advantage of a new habitat above the surface. For example, adult dragonflies are ferocious aerial predators of other insects. Contrastingly, adult mayflies do not eat at all, but simply use their short adult life stage to fly around and find a mate.
Finally, consider butterflies. Unlike frogs and aquatic insects, a butterfly lives on land for its whole life. However, butterflies use different food sources at different stages. For example, the monarch butterfly is in a close symbiotic relationship with the milkweed plant. As a caterpillar, the monarch eats the milkweed leaves. After metamorphosis, the adult butterfly eats a different part of the milkweed plant – the nectar of the milkweed flowers. As an added benefit, when the adult butterfly drinks flower nectar, it pollinates milkweed plants, which helps the plants reproduce. Thanks to the butterfly’s pollination services, a new generation of milkweed plants will grow, providing leaves for future caterpillars to eat!
Study Metamorphosis with Wild Earth Lab!
Whether you’re teaching your students about the metamorphosis of amphibians or insects, I’ve got the perfect learning resources for you! These sets include all the printable materials you need for studying amphibians and aquatic insects – including life cycle diagrams and much, much more!
Explore more lessons from Wild Earth Lab:
If you enjoyed this post, I know you will love trying my other printable science and nature units in your classroom too!
-
Reptiles: a science unit exploring reptile adaptations, traits, & biodiversity$12.00 -
Mammals: a science unit exploring mammal traits & biodiversity$10.00 -
Product on sale
Forest Bundle: 3 cross-curricular forest units!Original price was: $30.00.$24.00Current price is: $24.00. -
Birds of Prey: a raptor unit for kids$8.00
Are you interested in reading more posts about wildlife and ecology? Subscribe or follow Wild Earth Lab using the links below!
References and Further Reading
- Clark, M.A., Douglas, M., and Choi, J. (2018). Biology. Open Stax. Ch 29.3. Available: https://openstax.org/books/biology-2e/pages/29-3-amphibians
- Fowler, S., et al. (2013). Concepts in Biology. OpenStax. Ch 15.6. Available: https://openstax.org/books/concepts-biology/pages/15-6-vertebrates
- Natural History Museums of Los Angeles County (n.d.). Marvelous Metamorphosis. Available: https://nhmlac.org/marvelous-metamorphosis
- San Diego Zoo (n.d.). Salamander and Newt. Available: https://animals.sandiegozoo.org/animals/salamander-and-newt
- Wake, DB and Koo, MS. 2018. Primer: Amphibians. Current Biology 28(21): R1237-R1241. https://doi.org/10.1016/j.cub.2018.09.028
