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

Slovenia Slovenia, officially the Republic of Slovenia, is a country in Central Europe. It borders Italy to the west, Austria to the north, Hungary to the northeast, Croatia to the south and southeast, and a short (46.6 km) coastline within the Adriati ...

zoologist Zoology ( , ) is the scientific study of animals. Its studies include the structure, embryology, classification, habits, and distribution of all animals, both living and extinct, and how they interact with their ecosystems. Zoology is one ...

Serbian Serbian may refer to: * Pertaining to Serbia in Southeast Europe; in particular **Serbs, a South Slavic ethnic group native to the Balkans ** Serbian language ** Serbian culture **Demographics of Serbia, includes other ethnic groups within the co ...

origin.

Biography

Hadži was born in a Serbian family in Temišvar (today

Timișoara Timișoara (, , ; , also or ; ; ; see #Etymology, other names) is the capital city of Timiș County, Banat, and the main economic, social and cultural center in Western Romania. Located on the Bega (Tisza), Bega River, Timișoara is consider ...

Romania Romania is a country located at the crossroads of Central Europe, Central, Eastern Europe, Eastern and Southeast Europe. It borders Ukraine to the north and east, Hungary to the west, Serbia to the southwest, Bulgaria to the south, Moldova to ...

) in what was then

Austria-Hungary Austria-Hungary, also referred to as the Austro-Hungarian Empire, the Dual Monarchy or the Habsburg Monarchy, was a multi-national constitutional monarchy in Central Europe#Before World War I, Central Europe between 1867 and 1918. A military ...

. 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, north of the country, along the Sava river, at the southern slopes of the ...

. 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 (, , ), abbreviated UL, is the oldest and largest university in Slovenia. It has approximately 38,000 enrolled students. The university has 23 faculties and three art academies with approximately 4,000 teaching and re ...

. 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 ( (SAZU)) is the national academy of Slovenia, which encompasses science and the arts and brings together the top Slovene researchers and artists as members of the academy. Cultural significance Establis ...

(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 Phyla, the plural of ''phylum'', may refer to: * Phylum, a biological taxon between Kingdom and Class * by analogy, in linguistics, a large division of possibly related languages, or a major language family which is not subordinate to another Phy ...

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

Parazoa Parazoa (Parazoa, gr. Παρα-, para, "next to", and ζωα, zoa, "animals") is an obsolete subkingdom that is located at the base of the phylogenetic tree of the animal kingdom in opposition to the subkingdom Eumetazoa; they group together t ...

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

Chordata A chordate ( ) is a bilaterian animal belonging to the phylum Chordata ( ). All chordates possess, at some point during their larval or adult stages, five distinctive physical characteristics (Apomorphy and synapomorphy, synapomorphies) th ...

. 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 Platyhelminthes (from the Greek πλατύ, ''platy'', meaning "flat" and ἕλμινς (root: ἑλμινθ-), ''helminth-'', meaning "worm") is a phylum of relatively simple bilaterian, unsegmented, soft-bodied invertebrates commonly called ...

evolved from

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

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 (; : nuclei) 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, have no nuclei, and a few others including osteoc ...

became separated by

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

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 animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

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

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

. 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 (), also called the Grand Prešeren Award (), is the highest decoration in the field of artistic and in the past also scientific creation in Slovenia. It is awarded each year by the Prešeren Fund () to two eminent Slovene art ...

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