COMPARATIVE ANATOMY: HISTORY, OBJECT OF STUDY, METHODOLOGY - ANATOMY AND PHYSIOLOGY - 2024

The comparative anatomy is a branch of zoology that is responsible for studying the differences and similarities that exist in the morphology of different living things. This discipline is closely linked to descriptive morphology and is used to develop studies that address kinship between species (phylogeny).

The objective of comparative anatomy is directed towards the adaptive changes that organisms experience during evolution; consequently, the contributions of this discipline have been essential for the evolutionary study of vertebrate species.

Vertebrate organisms share a similar morphology because they come from the same ancestor. Source: pixabay.com

Comparative anatomy is also used within the research fields of other sciences, such as medicine or paleontology. For this reason, the author Virginia Abdala in her work Comparative anatomy (2006), affirms that this branch can be defined as a complementary science that serves to support other studies.

The naturalist Charles Darwin (1809-1882) used comparative anatomy to establish that the similarities between different animals are due to the fact that their structures were inherited from a very distant common ancestor.

This means that certain vertebrate organisms share a similar morphology because they come from the same ancestor. However, this morphology underwent considerable changes over the years, as it had to adapt to different environments.

For example, Darwin considered the similarities that exist between the skeleton of a dolphin and that of a human being, despite the fact that both bodies are designed to perform different functions, such as walking or swimming.

History

From prehistory to the Greeks

The author Jorge Duque, in his text Historia de la anatomía comparada (2014), established that the origins of this discipline are very old, since the first representatives of our species tried to understand their own morphology by comparing it with that of the animals that hunted.

Consequently, the author asserts that a specific date of the origin of comparative anatomy cannot be established, since it possibly occurred long before the emergence of written history.

The first texts to be found on comparative anatomy were written by Aristotle (384-322 BC), who based his anatomical studies on the information he obtained from the bodies of both animals and humans. Historians claim that Aristotle did not dissect human corpses, but did manage to examine fetuses.

Likewise, Aristotle used experimentalism as a study method, which allowed him to carry out anatomical writings on invertebrate and vertebrate organisms. This is one of the reasons why some authors consider him the father of comparative anatomy.

The investigations of Erasistratus

Later, Erasistratus de Ceos (310-250 BC) carried out some comparative anatomy studies in different species in order to deduce the relationship between function and structure of anatomical parts.

Erasistratus managed to describe the blocking function performed by the epiglottic cartilage, which is responsible for stopping the passage of air when the elements are ingested. This analysis was revolutionary for the thinking of the time, since at that time it was believed that liquids and food could enter both the stomach and the lungs.

At the time of Erasistratus, the dissection of human corpses was restricted, which forced the researcher to perform comparative anatomy, finding similarities in the morphology of the animals.

XVII century

At the end of the 17th century, scientists returned to an interest in comparative anatomy, since descriptive anatomy did not fully motivate anatomists. This was because the researchers considered it static, since it only recorded the appearance and texture of the parts.

On the contrary, comparative anatomy made it possible to establish different perspectives on a certain part of the body, thus greatly expanding the knowledge of anatomists.

What is studying (object of study)

The word "Anatomy" comes from the late Latin anatomia, which in turn derives from the Greek loanword anatomé, which means "dissection."

It is the science whose object of study is the form, structure and relationships of the body parts of organisms; This is achieved through the dissection of different living beings.

Comparative anatomy - the branch of zoology and anatomy - is also responsible for studying the structure of living beings, however, its main objective is to compare some morphologies with others, in order to describe the similarities and differences that They exist between each species, especially in vertebrates.

Through morphology, comparative anatomy studies the structure of organs and bones. Source: pixabay.com

Methodology

Morphology

Comparative anatomy uses morphology as a method to carry out its investigations. This is because morphology is a branch of biology that allows studying the characteristics of an organism, which includes both the elements of external appearance (structure, shape and color) and the elements of internal structure (organs and bones.).

Physiology

Comparative anatomy also uses physiology to establish the similarities and differences between organisms. This is because physiology as a discipline is dedicated to understanding the mechanisms that work within a living system.

In fact, some historians affirm that physiology was one of the fundamental bases to build the rest of the medical and biological sciences, since through this discipline the functioning of any system can be known, ranging from organs and bones to organs. biomolecules and cells.

Concepts of homology and analogy

To carry out its studies, comparative anatomy uses two important concepts: analogy and homology.

For example, when it is determined that two morphologies are analogous, this means that the species have a different origin, although they maintain a common use of a certain part of the body.

On the other hand, when it is established that two morphologies are homologous, this means that the species maintain a common origin, but give a different use to that part of the body that is being compared.

By way of conclusion, it can be said that the wings of a hummingbird and a dragonfly are homologous parts, while the fin of a whale and a human arm are analogous parts.

References

1. Abdala, V. (2006) Comparative anatomy: its validity as a research program. Retrieved on September 29, 2019 from Researchgate: researchgate.net
2. Cole, F. (1917) The history of comparative anatomy. Retrieved on September 30, 2019 from JSTOR: jstor.org
3. Duque, J. (2014) History of comparative anatomy. Retrieved on September 30, 2019 from Scielo: scielo.conicyt.cl
4. Kappers, C. (1936) The comparative anatomy of the nervous system of vertebrates, including man. Retrieved on September 30, 2019 from Psycnet: psycnet.apa.org
5. Ogura, Y. (1972) Comparative anatomy of vegetative organs. Retrieved on September 30, 2019 from Schweizerbart: schweizerbart.de
6. Owen, R. (1855) Lectures on the comparative anatomy and physiology of the invertebrate animals. Retrieved on September 30, 2019 from Google books: books.google.com
7. SA (sf) Comparative anatomy. Retrieved on September 29, 2019 from Wikipedia: es.wikipedia.org
8. Suárez, B. (2006) Comparative anatomy and evolution of species. Retrieved on September 29, 2019 from Accefyn Magazine: accefyn.com