All living beings have the ability to produce new cells and tissues, which guarantees the proper functioning of the body, as well as being able to heal from certain wounds. However, in the animal world we find that there are species that go beyond being able to carry out this process, since they can regenerate certain organs, some even vital, or even limbs.
Do you want to know examples of animals that regenerate to find out how they do it? We invite you to continue reading this article on our site to expand your knowledge on this topic.
What is animal regeneration?
Animal regeneration is a process that consists of the production of tissues or new body structures that need to be replaced, either because they are have been lost or because they have been damaged. It occurs in several types of animals, which are grouped from the taxonomic point of view in different ways. In this sense, some species can regenerate vital organs and other certain extremities. However, we must bear in mind that, in general, all living beings have a certain regenerative capacity of their tissues, an example of which is wound healing.
Given the fact that species belonging to different phyla share this regenerative capacity, it has been estimated that this could be a characteristic of a common ancestor, which later, due to certain genetic processes, was lost or restricting in some groups, as is the case of mammals, in which this function is more limited. It has also been speculated that this may have emerged independently in species exhibiting this trait.
How does regeneration occur in animals?
The development of living beings is configured by a dynamic controlled by genes, which determine how each species develops, from the formation of the embryo to the final changes that can occur in the individual. In this way, this same genetic mechanism that acts in the formation of cells, tissues and organs, has to do with the regeneration of certain parts of the body in some animals. In this sense, for this regenerative capacity to occur, the genetic processes codified for these cases must be activated.
Regeneration in animals can be activated in different ways depending on the species. Thus, it can happen almost immediately when the loss of a body part occurs in animals such as planarians, but it occurs differently in animals such as certain insects, which, in case of losing a limb, for example, it is It will be restored as the different changes that the animal goes through occur.
Another example of animal regeneration is found in certain reptiles. In these animals, if, for example, they lose their tail, it regenerates, but it will not always have the same length as the original. On the other hand, age can influence the regenerative capacity of species.
Mechanisms for regeneration in animals
This regeneration process can occur through two mechanisms:
- Epimorphosis: consists of the formation of an undifferentiated tissue known as blastema, where a cell proliferation occurs that will give rise to to the damaged or missing structure.
- Morphalaxis: regeneration occurs from existing tissue where the injury occurred, no previous tissue such as blastema is formed. In other words, existing tissues are transformed to give rise to regeneration, while with epimorphosis new tissues are created.
Epimorphosis has been described, for example, in flatworms, amphibians and ophiuroids; while morphalaxis in hydras and asteroids.
Examples of animals that regenerate
Next, let's learn about specific examples of animals that regenerate:
Planaria
Planarian correspond to a diverse group of flatworms that have an amazing capacity to regenerate, since half or a piece of the animal, can originate from another individual This process is due to the presence of stem cells distributed throughout the animal's body, which are regulated by genetic mechanisms and are activated to produce the regeneration of these animals. It is a type of asexual reproduction that occurs in more animals, find out in this other article: "Asexual reproduction in animals".
Hydras
Hydra corresponds to the genus of a group of animals that belong to the cnidarian phylum, which also have an important regeneration potential. Its ability includes regenerating a new individual from a piece of tissue or even isolated cells from the animal. All this process occurs from a complex molecular and cellular base system that allows the development of this peculiar property.
Salamanders
If there are some animals that regenerate in a very peculiar way, they are the members of the Salamandridae family, since they have the ability to regenerate various tissues of their body several timesIn this way, they can cause the tail, parts of organs such as eyes, brain, heart and jaw to re-grow. The mechanism used by these animals is different from the processes that occur in metamorphosis (they are amphibians, so the larva undergoes a transformation to reach the adult stage). Regeneration occurs by mechanisms produced by skeletal muscle fibers that are activated in these cases, which are different from that of stem cells.
Lizards
In reptiles we also find examples of animals that regenerate and, although the process is absent in several members of the group, in others, mainly in various small or medium-sized lizards, regeneration takes place, but not with the ability of salamanders.
A clear example is the process known as autonomy, through which certain lizards can voluntarily shed part of their tailto distract a predator. Then, a regeneration begins that allows part of the limb to be rebuilt, although the bone does not regenerate and it does not usually form the same original size. Geckos carry out this type of regeneration.
Get to know all the Types of lizards in this other article.
Sea stars
Within the echinoderms we find the class Asteroidea, which is made up of starfish. Various species of these animals exhibit regenerative capacity of their arms, although it is also an asexual reproduction strategy in them. Some species have greater potential to carry out this process, such as the common comet star (Linckia guildingii). The regeneration of these invertebrates includes two types: rebuild one of the extremities; generate even a new individual from half of the original.
Generally, for the emergence of a new individual to occur, some portion of the central disc of the animal must be present, but certain genera, such as Linckia and Coscinasterias, can do so without the need for this circular structure to be present.
Zebrafish
Within vertebrates, the zebrafish (Danio rerio) stands out for its regenerative capacity of its caudal fin and also of its heart. In the case of amputation of the first, a series of stages occur, such as: wound healing, restitution of the epidermis, formation of the blastema and finally the differentiation of the tissue in the new fin. On the other hand, these fish, in case of heart damage, also have the ability to activate cellular processes that restore the functioning of this vital organ.
