What is the Difference Between Neoteny and Paedogenesis

The key difference between neoteny and paedogenesis is that neoteny is the process of delaying the physiological development of an organism, while paedogenesis is the process of reproduction by an organism that has not achieved physical maturity.

Paedomorphism is the retention of traits by an adult that was previously seen in the young. Paedomorphism is a type of heterochrony. It is a specific subject in the field of developmental biology. There are two ways paedomorphism take place: neoteny and paedogenesis. In neoteny, the physiological development of an organism is delayed, while in paedogenesis, sexual development occurs faster.

CONTENTS

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

What is Neoteny?

Neoteny is the process of delaying the physiological development of an organism. It is also called juvenilization. This process slows down the somatic development of an organism. It is typically found in animals and modern humans. Neoteny and paedogenesis are two types of paedomorphism. Paedomorphism is a type of heterochrony. It is the retention in adults the traits that were previously seen in the young. In evolutionary biology, domestication and evolutionary developmental biology, such retentions are very important. Some scientists define paedomorphism as the retention of larval traits in adults, as seen in salamanders.

This term was coined by Julius Kollmann. In 1926, Louis Bolk described neoteny as a major process in humanization. The neoteny in humans is the slowing or delaying of body development compared to non-human primates. It results in features such as a large head, a flat face, and relatively short arms. However, humans also have non-neotenic (peramorphic) traits such as large noses and long legs. Moreover, neoteny is also present in domesticated animals such as dogs and mice. This is because they have more resources and less competition for those resources, allowing them to mature and reproduce more quickly than their wild counterparts.

What is Paedogenesis?

Paedogenesis is the process of reproduction by an organism that has not achieved physical maturity. In fact, it is a mechanism associated with paedomorphism. It is mainly discussed in developmental biology. Paedogenesis can be described as the attainment of sexual maturity by an organism while in its larval or juvenile stage. Organisms that show paedogenesis never achieve the adult form experienced by their previous evolutionary ancestors.

Paedogenesis occurs mainly due to environmental conditions such as low temperature, lack of iodine leading to low thyroid gland activity, etc. These environmental conditions inhibit metamorphosis. If the environmental condition improves, paedogenesis can be reversed. This biological concept is present in certain amphibians and some insects. Furthermore, it also occurs in the females of certain beetles, strepsiptera, bagworms, and gall midges.

What are the Similarities Between Neoteny and Paedogenesis?

• Neoteny and paedogenesis are two ways by which paedomorphism arises in an organism.
• Both neoteny and paedogenesis are related to developmental biology.
• These processes are due to a heterochronic change.
• Both processes inhibit normal metamorphosis.

What is the Difference Between Neoteny and Paedogenesis?

Neoteny is the process of delaying the physiological development of an organism. In contrast, paedogenesis is the process of reproduction by an organism that has not achieved physical maturity. So, this is the key difference between neoteny and paedogenesis. Furthermore, in neoteny, the physiological development of an organism is delayed, while in paedogenesis, sexual development occurs faster.

The below infographic lists the differences between neoteny and paedogenesis in tabular form for side by side comparison.

Summary – Neoteny vs Paedogenesis

Paedomorphism is a type of heterochrony that results in the retention of traits by an adult that were previously seen in the young. Neoteny and paedogenesis are two ways that promote paedomorphism in an organism. Neoteny is the process of delaying the physiological development of an organism, while paedogenesis describes the reproduction by an organism that has not achieved physical maturity. Thus, this is the key difference between neoteny and paedogenesis.

Reference:

1. “Neoteny.” An Overview | ScienceDirect Topics.
2. “Paedogenesis.” An Overview | ScienceDirect Topics.

Image Courtesy:

1. “Neoteny” By Mchavez – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “Notophthalmus perstriatus: Striped Newt” By Todd Pierson (CC BY-NC-SA 2.0) via Flickr