BIO354H5 Lecture 10: BIO354 Lecture 10
Document Summary
Limbs - referring to any locomotory functioning part. Kind of like what a typical tetrapod would have without digits. Fins are thin in sharks for locomotion - keratinized connective tissue. Fish have more bony and cartilaginous fins. Clade with fins - fins that aren"t homologous with jaw vertebrates. No good indication for template of fin development. With advent of jaws - enhancement of feeding - organism"s now have choice to filter feed and have capacity to target larger prey. The chase for prey probably started in this same time. Fins initiate better relation between predator and prey. Lamprey - modified so much in general anatomy because they have such a specialized function. Hard to use as primitive jawless fish. The hox genes must code for fins - taxa without fins share gene called pdx. Tbx gene - responsible for lateral fin folds. Assume that fin folds become segregated as anterior and posterior by separating gene into 2 tbx4 and tbx5.
