What Is Metamorphosis In Animals?
We know that metamorphosis in animals can entail a major change in their appearance, although this also implies a number of important physiological changes that are not well known. Metamorphosis occurs in insects, amphibians, molluscs and crustaceans.
It seems a little strange to us that, before it was a butterfly, this beautiful insect with colored wings was a caterpillar … How could it have changed so much? Well, it’s thanks to a mechanism used by several animals. If you want to know more about what metamorphosis is, don’t hesitate to read the following article that we put at your disposal.
What is metamorphosis?
It is a biological and natural process thanks to which an animal changes its shape, from birth to adulthood or maturity. When we ask what metamorphosis is, we cannot say that it is the transformation process “from caterpillar to butterfly”, since the mechanism is much more complex.
Several insects, molluscs, amphibians, crustaceans and echinoderms undergo this transformation, which is related to changes in behavior and habitat.
The metamorphosis into insects
We’ll start by explaining what metamorphosis in insects is, because they’re generally the best known to us, although, of course, they’re not the only ones. In them, the process involves the disruption of larval tissues and replacement in cell numbers.
Furthermore, it is noteworthy that, in insects, this mechanism occurs in several stages: first the larvae or nymph, then the pupa and finally the adult stage. In the middle of each growth phase there is a phase of changing the protective “armor”.
Within the metamorphosis of insects we can highlight two main types: on the one hand, hemometabolism, a simpler process by which an individual goes through different changes without ceasing to feed. Examples of this type of metamorphosis occur in locusts and bedbugs.
On the other hand, holometabolism is more complex because the egg is born as a larva and must go through several changes before entering the pupa and then completing growth. In several steps, he stops eating and becomes immobile. This process occurs in 80% of insects, such as butterflies, beetles, flies and wasps.
In both cases, the effector hormones are responsible for carrying out the growth and metamorphosis of the insect, through various signals sent to the brain. Furthermore, the molting process is related to neuronal and environmental signals, as well as the circadian rhythm. This increases hormone production and activates growth.
The metamorphosis into amphibians
If we ask what metamorphosis in amphibians is, basically we have to refer to a large change from larvae or tadpole to an adult.
During this growth, the individual prepares to live out of water, since at birth he can swim and breathe through his gills. Furthermore, it is aided by a tail and a circular mouth, and is of a smaller size.
Subsequently, the fore and hind legs grow. The tail and pointed teeth disappear and change the type of breathing, adapted to terrestrial life, through the lungs.
But if all of the above isn’t enough, the skull changes from cartilaginous to bony and the tongue muscles develop. Although these animals return to water to reproduce and spawn, they will no longer be in an aquatic environment.
In these cold – blooded animals, the bubble is controlled by two hormones secreted by the thyroid gland: thyroxine (or T4) and triiodothyronine (T3), the latter being the most important.
The metamorphosis into molluscs and crustaceans
In a third group we can include the annelids, crustaceans, echinoderms and molluscs, which carry an “incomplete” metamorphosis. This means that individuals are born looking very similar to what they have as adults, but the main difference is that with each change they develop more complex structures that are suitable for reproduction.
One of the best-known cases of metamorphosis in crustaceans is that of the crab, which “leaves its house” or carapace when, over time, it gets smaller.