It seemed not too long ago that we were watching the world reawaken from its frozen slumber. Now we are now bearing witness to important stages in their lifecycle, a glimpse into metamorphosis. Metamorphosis describes the process of transformation that some organisms go through to reach their adult form. In order to be considered metamorphosis, the life cycle must consist of two or more distinct stages. There are three types of metamorphosis, reflecting the amount of change observed in the life cycle of the organism.
Organisms that go through complete
metamorphosis like insects, amphibians, and fish are called holometabolous.
These animals begin life as eggs and from there develop into a larvae, pupae,
and finally adults. Perhaps the most renowned animal that undergoes complete
metamorphosis is the butterfly. A butterfly begins life as an egg then hatches
as a very hungry caterpillar (larva). As soon as the caterpillar has stored
enough fat, it enters the pupal stage where it weaves a cocoon around itself
known as a chrysalis. During this stage, special cells needed for the
transformation to adulthood grow rapidly. When the butterfly sheds its cocoon
it has entered the adult stage and is equipped for reproduction.
Frogs also begin life as eggs, but they soon hatch as tadpoles. Then they develop into froglets, and finally transform into frogs. Their metamorphic life cycle has them begin life in the water. Hormones and feeding behavior cause them to grow hind legs and lose their gills. When they reach adulthood they are fully equipped for the great amphibian migration where they will seek out mates and begin the cycle of life anew.
Like butterflies and frogs, fish also begin their life as eggs in the water, but hatch as larvae. As the yolk sac, which provides nutrients, begins to disappear their swim bladder becomes active to the point where the larvae can feed itself. At this point it is called a fry. As the fry grows scales and fins they transform into juveniles or fingerlings which are about the size of a human finger. Fish are considered fingerlings until they are fully grown and capable of reproduction.
Though their metamorphic stage names may differ, each example reviewed here shares one thing in common. Each organism relies on a steady diet to release the hormones that trigger metamorphosis. Without the nutrients required for metamorphosis, the life cycle is broken.
As you get outside this summer, be on the lookout for nature’s transformers. Look for chrysalis’ in bushes or froglets and frys in and along streams. Nature is always changing, perhaps you can catch it in its transformation! As always, appreciate the beauty and wonder of nature, but be gentle. Respect wildlife by keeping a safe distance from them so as not to disturb them, no matter what life stage they are in.