L1 Diversity of fish

Question 1

What do we consider a “fish”?

Answer 1

Organism with:
- cranium
- Aquatic habitat
- Use gills
- Have fins

Question 2

Agnatha (jawless fish), describe members

Answer 2

Hagfish
- sensory barbels around head
Lampreys
- Adult oral suction disk w keratinous teeth
- larval burrow, adult spawn freshwater

Question 3

Class Actinopterygii versus Sarcopterygii

Answer 3

Sarcopterygii - fleshy finned
- tetrapods (7 spp we still consider fish)
- Coelocanth: living fossil
- lungfish : atrium incompletely divided (amost 3 chambered), respire through air bladder
Actinopterygii - ray finned
- Chondrostei : sturgeons and paddlefish
—– strong visible asymmetry in caudal fin
- Neopterygii : respiratory air bladders, warm low O2 habitat
—–Teleostei : caudal fin bones support the lower lobe, externally looks symmetrical