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Title:Ontogenetska variabilnost lobanje velikega hrčka, Cricetus cricetus (linnaeus, 1758)
Authors:Breznik, Urška (Author)
Klenovšek, Tina (Mentor) More about this mentor... New window
Kryštufek, Boris (Co-mentor)
Files:.pdf MAG_Breznik_Urska_2019.pdf (2,36 MB)
MD5: E066F8D99A70C0D0EEADA0F5ED0A8296
 
Language:Slovenian
Work type:Master's thesis/paper (mb22)
Typology:2.09 - Master's Thesis
Organization:FNM - Faculty of Natural Sciences and Mathematics
Abstract:Veliki hrček, Cricetus cricetus je velik in robusten glodavec s kratkim repom. V osnovi naseljuje kulturne in gozdne stepe. Razširjenost velikega hrčka sega od Evrope do Azije. Dlaka je za glodavce nenavadno obarvana. Za velikega hrčka je značilen barvni polimorfizem, ki je najpomembnejša značilnost posameznikov in populacijske variabilnosti. Naš cilj je bil analizirati morfološko variabilnost ventralne strani lobanje velikega hrčka med ontogenetskim razvojem ločeno po spolu. Uporabili smo metode geometrijske morfometrije, ki so nam omogočile ločeno obravnavo velikosti in oblike lobanje. Material so predstavljale lobanje hrčka, ki so bili rojeni v ujetništvu, rejeni in usmrčeni v okolici Prage na Češkem. Starost materiala je bila natančno znana - starostne kategorije od mladičev do odraslih živali. Vzorec je predstavljal 134 lobanj iz zbirke na Karlovi univerzi v Pragi, od katerih smo jih uporabili 125. Osebki so bili razdeljeni v 10 starostnih skupin, od najmlajših starih manj kot 30 dni, do najstarejših v četrtem koledarskem letu življenja. Potrdili smo prisotnost sekundarnega spolnega dimorfizma v velikosti lobanje, ne pa tudi v obliki. Sekundarni spolni dimorfizem v velikosti lobanje se je pojavil pri starosti 120 dni. Od starosti 120 dni dalje, so samice rastle počasneje od samcev, kar se je pokazalo v večji velikosti lobanj samcev. Na podlagi tega smo zaključili, da do razlik v starostnih manifestacijah spolnega dimorfizma in postnatalne rasti lobanje prihaja zaradi različnih smeri selekcije. Oblika lobanje se je spreminjala glede na starostne skupine. Primerjava najmlajših in najstarejših osebkov je pokazala, da imajo mlade živali širšo in bolj zaobljeno lobanjo, krajši in ožji gobčni del, relativno daljši niz zgornjih meljakov, večji bobnični mehur in ožja oziroma manj usločena lična loka. Primerjava velikosti in oblike lobanje med starostnimi skupinami je pokazala najvišjo stopnjo sprememb v velikosti in obliki do 150 dneva starosti. Po 450 dnevu so bile spremembe v velikosti in obliki neznatne. Z raziskavo ontogenetske alometrije smo dokazali tesno povezavo med obliko in velikostjo lobanje. Lobanja je rastla alometrično, kar pomeni, da so posamezni segmenti lobanje med ontogenetskim razvojem rastli z različno hitrostjo in se je tekom rasti posledično spreminjala tudi oblika lobanje. Iz tega smo sklepali, da alometrična rast pri velikem hrčku pomembno vpliva na razvoj in obliko lobanje v odraslem stanju.
Keywords:Cricetus cricetus, geometrijska morfometrija, lobanja, ontogenija, alometrija, spolni dimorfizem.
Year of publishing:2019
Publisher:[U. Breznik]
Source:Maribor
UDC:599.323.83:591.152(043.2)
COBISS_ID:24973320 New window
NUK URN:URN:SI:UM:DK:GDCWLHQV
Views:518
Downloads:66
Metadata:XML RDF-CHPDL DC-XML DC-RDF
Categories:FNM
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:30.09.2019

Secondary language

Language:English
Title:Ontogenetic variation of the skull of the common hamster, Cricetus cricetus (linnaeus, 1758)
Abstract:Common hamster is a big and robust rodent with a short tail. It inhabits the cultural and forested steppe. Its distribution extends from Europe to Asia. The common hamster is characterized by color polymorphism, which is the most important feature of individuals and population variability. The aim of this study was to analyze the morphological variability of the ventral side of the skull between sexes and ontogenetic development. We used geometric morphometric methods which allowed us to separately analyse shape and size of the skull. The material used in the assignment was the skull of a large hamster obtained from the collection of prof. dr. Vladimir Vohralik from Charles University in Prague. All specimens came from captivity, and the age was known exactly. The specimens were divided into 10 age groups, from the youngest, less than 30 days old, to oldest in the fourth calendar year of life. We confirmed the presence of secondary sexual dimorphism in size, but not in shape of the skull. Secondary sexual dimorphisms appeared at the age of 120 day. From this day on females started to grow slower than males, which was reflected in larger sized skull of males. In our opinion, the differences in age manifestations of sexual dimorphism and postnatal skull growth were determined by the different directions of selection. The shape of the skull varied according to age groups. We compared the skulls of the youngest and oldest specimens, and found that young animals, compared to adults, had a wider and more rounded skull, shorter and narrower muzzle, a relatively longer row of upper molars, a larger tympanic bulla and a narrower zygomatic arch. Comparison of skull size and shape between age groups showed the highest growth rate up to 150 days of age, after 450 days growth is insignificant. A study of ontogenetic allometry found a close relationship between the shape and size of the skull. The skull grew allometrically, which means that the individual segments of the skull during ontogenetic development grow at different speeds and, consequently, the shape of the skull changes in the course of growth. From this we concluded that allometric growth in a common hamster had a significant influence on the development and shape of the skull in adulthood.
Keywords:Cricetus cricetus, geometric morphometrics, skull, ontogeny, allomety, sexual dimorphism


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