Jovan Hadži (; 22 November 1884 – 11 December 1972) was a

Slovenia Slovenia ( ; sl, Slovenija ), officially the Republic of Slovenia (Slovene: , abbr.: ''RS''), is a country in Central Europe. It is bordered by Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the southeast, an ...

zoologist Zoology ()The pronunciation of zoology as is usually regarded as nonstandard, though it is not uncommon. is the branch of biology that studies the Animal, animal kingdom, including the anatomy, structure, embryology, evolution, Biological clas ...

of Serbian origin.

Biography

Hadži was born in a Serbian family in Temišvar (today

Timișoara ), City of Roses ( ro, Orașul florilor), City of Parks ( ro, Orașul parcurilor) , image_map = Timisoara jud Timis.svg , map_caption = Location in Timiș County , pushpin_map = Romania#Europe , pushpin_ ...

Romania Romania ( ; ro, România ) is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern, and Southeast Europe, Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, S ...

) in what was then

Austria-Hungary Austria-Hungary, often referred to as the Austro-Hungarian Empire,, the Dual Monarchy, or Austria, was a constitutional monarchy and great power in Central Europe between 1867 and 1918. It was formed with the Austro-Hungarian Compromise of ...

. He began his career in

Zagreb Zagreb ( , , , ) is the capital (political), capital and List of cities and towns in Croatia#List of cities and towns, largest city of Croatia. It is in the Northern Croatia, northwest of the country, along the Sava river, at the southern slop ...

. In 1920, he moved to Ljubljana where he became the head of zoological institute at the then established

University of Ljubljana The University of Ljubljana ( sl, Univerza v Ljubljani, , la, Universitas Labacensis), often referred to as UL, is the oldest and largest university in Slovenia. It has approximately 39,000 enrolled students. History Beginnings Although certain ...

. Between 1951 and 1972, Hadži was the head of the Biological institute at

Slovenian Academy of Sciences and Arts The Slovenian Academy of Sciences and Arts ( sl, Slovenska akademija znanosti in umetnosti (SAZU)) is the national academy of Slovenia, which encompasses science and the arts and brings together the top Slovene researchers and artists as members o ...

(SASA). In 1938, he became a full member of SASA. Hadži proposed unique theories of animal evolution. He devised a system of classification in which he divided the animal kingdom into six phyla:

Protozoa Protozoa (singular: protozoan or protozoon; alternative plural: protozoans) are a group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic tissues and debris. Histo ...

Parazoa Parazoa (Parazoa, gr. Παρα-, para, "next to", and ζωα, zoa, "animal") are a taxon with sub-kingdom category that is located at the base of the phylogenetic tree of the animal kingdom in opposition to the sub-kingdom Eumetazoa; they grou ...

, "Ameria" (animals with no segments), "Oligomeria" (animals with few segments), "Polymeria" (animals with many segments) and

Chordata A chordate () is an animal of the phylum Chordata (). All chordates possess, at some point during their larval or adult stages, five synapomorphies, or primary physical characteristics, that distinguish them from all the other taxa. These fiv ...

. His choice of characters important for classification was generally discredited by his contemporaries, and the system was never accepted by zoologists. However, due to its simplicity, the system was widely used in science education in the former Yugoslavia. His other major theory was that of the origin of metazoa - he developed an existing hypothesis stating that the first multicellular animals resembling today's

flatworms The flatworms, flat worms, Platyhelminthes, or platyhelminths (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") are a phylum of relatively simple bilaterian, unsegment ...

evolved from

multinucleate Multinucleate cells (also known as multinucleated or polynuclear cells) are eukaryotic cells that have more than one nucleus per cell, i.e., multiple nuclei share one common cytoplasm. Mitosis in multinucleate cells can occur either in a coordinat ...

ciliate The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a ...

s in which

cell nuclei The cell nucleus (pl. nuclei; from Latin or , meaning ''kernel'' or ''seed'') is a membrane-bound organelle found in eukaryotic cells. Eukaryotic cells usually have a single nucleus, but a few cell types, such as mammalian red blood cells, h ...

became separated by

cellular membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane that separates and protects the interior of all cells from the outside environment (th ...

s. Again, the theory emphasized similarities of structure while disregarding other important characters, so it was never generally accepted. Hadži's faunistical work focused on the

invertebrate Invertebrates are a paraphyletic group of animals that neither possess nor develop a vertebral column (commonly known as a ''backbone'' or ''spine''), derived from the notochord. This is a grouping including all animals apart from the chordate ...

fauna of caves and mountains where he described more than a hundred new species and

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

. He was also an active cave explorer and acted as a president of the Ljubljana Cave Exploration Society (DZRJL) between 1927 and 1945. For his contributions to zoology, Hadži received

Prešeren Award The Prešeren Award ( sl, Prešernova nagrada), also called the Grand Prešeren Award ( sl, Velika Prešernova nagrada), is the highest decoration in the field of artistic and in the past also scientific creation in Slovenia. It is awarded each yea ...

in 1956. In 1969, he received the honorary doctorate by the University of Ljubljana. Several invertebrate species were named after him by other zoologists, such as '' Astagobius hadzii'', '' Cyclopina hadzii'', '' Isohypsibius hadzii'', and '' Niphargus hadzii''.

References

1884 births 1972 deaths Slovenian zoologists Academic staff of the University of Ljubljana Members of the Slovenian Academy of Sciences and Arts Prešeren Award laureates Levstik Award laureates Slovenian people of Serbian descent Serbs of Romania Scientists from Timișoara Yugoslav zoologists {{zoologist-stub