What is the Difference Between Epimorphosis and Morphallaxis

The key difference between epimorphosis and morphallaxis is that in epimorphosis, the majority of regeneration comes from cellular differentiation, while in morphallaxis, the majority of regeneration comes from reorganization or exchange.

Epimorphosis and morphallaxis are two types of tissue or organ regeneration processes in animals. There are three types of regeneration of tissue and organ in animals. They are epimorphosis, morphallaxis, and planarian regeneration. Epimorphosis is normally seen in salamander limbs. Morphallaxis occurs in the hydra, while planarian regeneration occurs in the planarians.

CONTENTS

1. Overview and Key Difference
2. What is Epimorphosis 
3. What is Morphallaxis
4. Similarities – Epimorphosis and Morphallaxis
5. Epimorphosis vs Morphallaxis in Tabular Form
6. Summary – Epimorphosis vs Morphallaxis

What is Epimorphosis?

Epimorphosis is defined as the regeneration of a specific part of an organism. It occurs via extensive cell proliferation of somatic stem cells, dedifferentiation, reformation, and blastema formation. Epimorphosis is a simple model for development in animals. However, it only occurs in tissues surrounding the site of injury rather than occurring system-wide in the organism. The evolutionary biologist Thomas Hunt Morgan was the first scientist to describe the process of epimorphosis. In epimorphosis, the majority of regeneration comes from cellular differentiation. This process restores the anatomy of the organism and the original polarity that existed before the destruction of the tissue or structure. Moreover, epimorphosis can be observed in both vertebrates and invertebrates, mainly in salamanders, annelids, and planarians.

Epimorphosis takes place in salamander limbs. This type of regeneration happens via the formation of a new part called a blastema. When amputation is sensed by a large number of somatic stem cells, they migrate to the wound area. These cells increase their cell division. At the wound area, the blastema forms, and blastema cells proliferate to regenerate the lost tissues. Furthermore, there is no significant re-patterning of the remaining tissue in this process.

What is Morphallaxis?

Morphallaxis is a type of regeneration tissue or organ in animals where the majority of regeneration comes from reorganization or exchange. This technique was discovered by evolutionary biologist Abraham Trembley. Morphallatic regeneration does not include the formation of blastemal, and there is no proliferation. Instead of forming blastemal and proliferation, in morphallaxis, the existing tissue undergoes re-arrangement and is transformed into new tissue or organ.

One classic example of morphallaxis is that of the hydra. When this animal is severed into two, the remaining severed sections form two fully functional and independent hydra. The most important feature of morphallaxis is that a large majority of regenerated tissue comes from already present tissue in the organism. This means one severed section of the hydra forms a smaller version of the original hydra. Furthermore, the new hydra is approximately the same as the severed section.

What are the Similarities Between Epimorphosis and Morphallaxis?

• Epimorphosis and morphallaxis are two types of tissue or organ regeneration processes in animals.
• They can be observed in invertebrates.
• Both processes are very important for the survival of the organism.
• These processes are studied by evolutionary biologists.

What is the Difference Between Epimorphosis and Morphallaxis?

Epimorphosis is a type of regeneration tissue or organ in animals where a majority of regeneration comes from cellular differentiation, while morphallaxis is a type of regeneration tissue or organ in animals where a majority of regeneration comes from reorganization or exchange. Thus, this is the key difference between epimorphosis and morphallaxis. Furthermore, epimorphosis was first described by Thomas Hunt Morgan, whereas morphallaxis was first described by Abraham Trembley.

The following table summarizes the difference between epimorphosis and morphallaxis.

Summary – Epimorphosis vs Morphallaxis

Epimorphosis and morphallaxis are two types of tissue or organ regeneration processes seen in animals. These processes are mainly observed in lower-order animals like invertebrates. In epimorphosis, the majority of regeneration comes from cellular differentiation. On the other hand, in morphallaxis, the majority of regeneration comes from reorganization or exchange. Salamanders, annelids, and planarians show epimorphosis, while morphollaxis is mainly shown by cnidarian hydra. So, this summarizes the difference between epimorphosis and morphallaxis.

Reference:

1. John L. Capinera. “Epimorphosis.” SpringerLink, Springer Netherlands.
2. “Morphallaxis.” Encyclopædia Britannica, Encyclopædia Britannica, Inc.

Image Courtesy:

1. “Myriapod post-embryonic development” By Hideyuki Miyazawa – Supplemantal Figure 1 in Miyazawa et al. (2014). “Molecular phylogeny of Myriapoda provides insights into evolutionary patterns of the mode in post-embryonic development”. Scientific Reports 4. DOI:10.1038/srep04127. (CC BY 3.0) via Commons Wikimedia
2. “Image from page 485 of “Biologisches Centralblatt” (1881)” Internet Archive Book Images (Public) via Flickr