Selkäjänteiset

Selkäjänteiset is the Finnish term for chordates, a phylum of animals that includes vertebrates. The defining characteristic of chordates is the presence of a notochord at some stage of their development. This flexible rod provides skeletal support and is a precursor to the vertebral column in many species. Other key features of chordates include a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail, although these may be present only transiently during embryonic development.

The phylum Chordata is remarkably diverse, encompassing a vast array of life forms. This includes well-known groups such as fish, amphibians, reptiles, birds, and mammals, all of which are vertebrates and possess a backbone. However, the phylum also includes simpler, invertebrate chordates like tunicates (sea squirts) and lancelets. These organisms exhibit the characteristic chordate features in their larval stages or throughout their lives, demonstrating the evolutionary history of the group.

Chordates occupy nearly every habitat on Earth, from the deepest oceans to the highest mountains, and from arid deserts to lush rainforests. Their ecological roles are equally varied, with chordates acting as predators, prey, herbivores, and decomposers, playing crucial roles in ecosystems worldwide. The study of chordates, or chordate biology, is fundamental to understanding animal evolution and biodiversity.