Osteichthyes Flashcards
What are the two main lineages of Osteichthyes?
- Sarcopterygii (lobe finned fish).
- Actinopterygii (ray finned fish).
What are the Sarcopterygii?
- Fish with lungs and gills. 8 species, 6 lungfish and 2 coelocanths.
Give characteristics of lungfish.
Originally thought to be specialised salamanders.
Dorsal, caudal and anal fins fused.
What are the two groups of Actinopterygii?
- Chondrostei (sturgeons and paddle fish).
- Neopterygii (teleosts).
Give characteristics of Chondrostei.
- Heterocercal tail.
- Ganoid scales.
- Spiracle.
- Ventral mouth.
Give characteristics of the Teleosts.
- Operculum has four bones.
- Homocercal tail.
- Elasmoid scales (2 thin layers).
- Ossified vertebrae.
- Premaxillary and maxillary bones make jaw movable.
- Highly manoeuvrable fins.
What are the features of gills?
- Gill rakers.
- Gill arch.
- Gill filaments.
- Lamellae.
Give facts on gills.
First vertebrate gas exchange organ.
Complex vasculature.
High surface area epithelium.
Talk about the evolution of the swimbladder.
- Early osteichthyes lived in freshwater and gulped air during periods of stagnation.
- First lungs were outpouches of the gut, allowing exchange of oxygen and carbon dioxide.
- These were ventral and made them top heavy.
- Modern bony fish have dorsal swim bladder.
- Advanced teleost swim bladders are no longer linked to gut and are filled with pure oxygen.
What does iteraparous mean?
Reproduce multiple times during life.
What does semelparous mean?
Reproduce with a big bang strategy.
Give three fish parental strategies.
Internal fertilisation/oviparous. e.g. guppies.
Care of young mouth brooding by female. e.g. tilapia.
Care of young by male. e.g. seahorses.
What does catadromous mean?
Juvenile stage saltwater, adults freshwater e.g. silver eel.
What does anodromous mean?
Juvenile stage freshwater, adults saltwater e.g. salmon.
What is the function of the gill arch?
Provide gill support.
