Evoluce sociálního chování může být usnadněna specifickými změnami v organizaci genomu, které snižují genetickou variabilitu jedinců v kolonii a podporují tak vzájemnou spolupráci. Jedná se zejména o haplodiploidii blanokřídlých a komplexní heterozygotnost některých všekazů. Zvláštní pozornost je věnována evoluci karyotypu sociálních pavouků. Diskutována je komplexní heterozygotnost objevená u některých ras australské maloočky Delena cancerides (Sparassidae). Srovnání stepníků rodu Stegodyphus (Eresidae) s různými úrovněmi sociálního chování ukazuje na snižování diploidního počtu u kvazisociálních zástupců a na vznik kryptických sociálních druhů. and Sociality is often accompanied by specific changes of genome organization, which could lead to the downsizing of genetic variability among sibs. In this review, we discuss the significance of haplodiploidy in Hymenoptera and complex sex-linked heterozygosity in some Isoptera for the evolution of social behaviour. Special attention is given to social spiders, where sex-linked heterozygosity arose in the huntsman spider Delena cancerides. Cytogenetic approaches have revealed cryptic speciation events in social spiders of the genus Stegodyphus, where rapid reductions of 2n seem to be linked with the evolution of sociality.
The changed socio-political conditions and transformation processes after 1989 had a significant impact on many spheres of life of our society. The text discusses these circumstances in connection with the issue of breastfeeding and its reflection from the perspective of mothers of two generations. The rise in popularity of breastfeeding and its preferences as the most appropriate method of nutrition in young children has been apparent for longer than adecade not only in Slovakia. This has been confirmed by works in the medical field as well as research on a specific sample of informants, on which the study is based. It attempts to reach an ethnological interpretation of the perception of breastfeeding by current mothers and women of an older generation. It confronts the attitudes of older women and current mothers towards breastfeeding and phenomena related thereto. It concludes that in recent years breastfeeding has been on the rise in comparison with the previous generation of mothers. The author considers the increased promotion of breastfeeding and the irreplaceability of breast milk in child nutrition to be the main factors contributing to this situation.
Struktura osídlení je u jednotlivých paleolitických kultur rozdílná. Cílem tohoto příspěvku je poukázat na odlišnosti v sídelní geografii s pomocí 3–D digitální kartografie. Zájmové území představuje mikroregion brněnské kotliny. Studovány jsou sídelní strategie bohunicienu, gravettienu/epigravettienu a magdaleniénu. and The settlement patterns of individual Palaeolithic cultures differ. This paper aims to demonstrate the variations in settlement geography with the aid of three–dimensional digital cartography. The study area is the Brno basin microregion, and settlement strategies of the Bohunician, Gravettian/Epigravettian, and Magdalenian are considered.