Difference Between Ontogeny and Phylogeny (With Table)

Ontogeny is focused on the study of individuals. It tries to debunk the processual steps of growth included in the development of a ‘complete’ organism. Conversely, Phylogeny is focused on the study of particular populations as against the individual organism. It is concerned with enhancing our understanding of how species develop and evolve over time.

Ontogeny vs Phylogeny

The difference between Ontogeny and Phylogeny is that the former is a specific branch of science that studies the growth and development of an individual organism, while the latter is also a branch of science, but it investigates the evolutionary process of development of any given species as a whole.

Comparison Table Between Ontogeny And Phylogeny

Parameters of ComparisonOntogenyPhylogeny
DefinitionOntogeny is the branch of science that investigates the historiography of an individual organism’s development.Phylogeny is the branch of science that investigates the evolutionary history of a particular species.
TranslationsOntogeny is a Greek word that can be translated to connote the ‘origin of being’.Phylogeny is a Greek word that can be translated to connote the ‘origin of tribes or kind’.
Emphasis Of AnalysisIndividuals are the focal point of all researches conducted within the field of Ontogeny.Populations are the focal point of all researches conducted within the field of Phylogeny
Central TheoryThe central theory of Ontogeny is based on the evaluation of the process of development of an organism from a single cell to a ‘complete’ organism.The central theory of Phylogeny is based on the evaluation of the complete trajectory of development that characterizes an entire species.
Application of the TheoryOntogenesis is important in the fields of developmental biology, developmental cognitive neuroscience, etc.Phylogeny is important in the fields of forensics, bioinformatics, etc.

What is Ontogeny?

Ontogeny is a scientific school of thought that studies and examines the process of an individual organism’s development. It takes into account the origin of the individual and the steps of development that the organism has lived through.

The word ‘Ontogeny’ has been derived from a Greek word that literally means the ‘origin of being’. Ontogenesis is focused on analyzing both the physiological and psychological development of an organism. Ontogeny is committed to examining the processual growth of the organism right from the fertilization of the egg to the presentation of the ‘whole’ organism.

Ontogeny believes that certain ancestral qualities are still preserved in an organism. It is at this juncture that Ontogeny is connected with Phylogeny, as an individual’s development and features cannot occur in a vacuum. They are inevitably a mirror image of the changes happening in the species as a whole. This creates the much-debated biogenetic model.

Ontogeny has an undeniable influence on the growth of developmental psychology, developmental cognitive neuroscience, developmental biology, and other disciplines.

What is Phylogeny?

Phylogeny is the study of the process of evolution that each species has experienced. It is focused on understanding the history of the evolutionary process. Derived from the Greek language, the word means the ‘origin of tribe or kind’.

The basis of this theory is that all organisms are genetically connected. These biological and genetic connections between various species can be effectively represented using a phylogenetic tree that traces the common ancestor among species.

Phylogeny is important to understand how organisms have retained certain ancestral features while also amalgamating new features that help species adapt to their ever-changing environments. Phylogeny is important in categorizing species as well as in the development of the fields of forensics and bioinformatics.

Phylogeny is closely associated with Ontogeny. Scientist Ernest Haekel stated that ‘Ontogeny recapitulates Phylogeny’- a statement that formed the basis of all biogenetic laws. However, this has been widely contested as it is not applicable to all organisms.

Main Differences Between Ontogeny and Phylogeny

  1. The main difference between Ontogeny and Phylogeny is that the former is the branch of science that investigates an individual organism’s historiography of development, while the latter term connotes the branch of science that studies the history of evolutionary development experienced by different species.
  2. The meaning of each term is also quite different. The word ‘Ontogeny’ can be translated to connote the ‘origin of being’. While the term ‘Phylogeny’ when translated means ‘origin of tribe or kind’.
  3. The two fields can be significantly differentiated on the basis of the focus points of each discipline. While Ontogeny focuses on a singular individual, Phylogeny is more focused on the history of the development of a given population or species.
  4. Ontogeny is centered around the understanding of the process of growth and development of a single organism right from the moment of fertilization to the formation of the ‘complete’ organism. While Phylogeny is rooted in investigating the whole evolutionary process.
  5. Ontogeny has an important contribution in augmenting our knowledge in the field of developmental psychology, developmental cognitive neuroscience, developmental biology, etc. On the other hand, Phylogeny is important in the study of forensics, bioinformatics, species classification, etc.

Conclusion

The science of evolution has successfully segmented into a number of renowned sub-disciplines over the years. Ontogeny and Phylogeny are two of the most important subfields with the expansive domain of studying developmental and evolutionary processes.

To a non-scientist, these two terms may seem overwhelmingly similar. However, both these areas of study are quite conspicuously different from each other. Ontogeny is dedicated to understanding how an organism develops right from the moment of fertilization to the formation of the ‘complete’ physiological and psychological being. The focus of such analysis remains the individual.

Alternatively, Phylogeny is more interested in examining the overall process of evolution experienced by particular species. It builds on the idea that several species may have similar trajectories of development and can hence be studied in further detail. The focus of such an investigation is not the individual but the group.

Although, Ontogeny and Phylogeny are closely interrelated as the evolutionary changes produced in an individual organism are not isolated from the changes happening in the population. However, they do have significant differences that need to be cognized to understand the subject matter of each discipline more accurately.

References

  1. https://www.cambridge.org/core/journals/paleobiology/article/conceptual-relationship-between-ontogeny-and-phylogeny/6A5D7B8BBA14E0E1356B49116600D757
  2. https://www.karger.com/Article/Abstract/115302
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