Sökning: "chondrichthyes"

Hittade 3 avhandlingar innehållade ordet chondrichthyes.

1. 1. Evolution of Vertebrate Eyes: a study on lens suspension and optical proterties

   Författare :Ola Gustafsson; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; evolution; eye; fish; crystalline lens; lens suspension; multifocal optical systems; Agnatha; Actinopterygii; Chondrichthyes; Vertebrate; Sarcopterygii;

   Sammanfattning : Many fishes have well-developed visual systems with color vision capabilities. The crystalline lens is the major refractive element in a fish eye since the cornea is optically inactive underwater. A typical fish eye has a large pupil and a lens of short focal length, features that increase light gathering ability. LÄS MER

3. 2. Basal Vertebrate Divergences from a Molecular Perspective

   Författare :Ann-Sofie Rasmussen; Biologiska institutionen; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mitochondrial genomes; Agnatha; Chondrichthyes; vertebrates; evolution; systematics; Genetics; cytogenetics; Genetik; cytogenetik;

   Sammanfattning : Fishes (Superclass Pisces) constitute the most numerous and morphologically diverse vertebrate group, yet only a small fraction of all molecular evolutionary studies concern piscine evolution. This thesis aims to investigate the vertebrate tree, through the analysis of mitochondrial (mt) DNA sequences. LÄS MER

4. 3. Comparatative studies on the IGF system in vertebrates : studies in rats, and in bony, cartilaginous, and jawless fish

   Författare :Katarina Drakenberg; Karolinska Institutet; Karolinska Institutet; []
   Nyckelord :IGF receptor; osteichthyes; chondrichthyes; cyclostomi; radioimmunoassay;

   Sammanfattning : Numerous studies have shown the importance of insulin-like growth factors (IGFs) for cellular growth, differentiation and metabolism in mammalian vertebrates. The mammalian IGF system, consists of IGF-1 and IGF-2, the IGF binding proteins (IGFBPs), and the type1 and type 2 IGF receptors. LÄS MER