Figure 13.14: Fish play an important role in many cultures, including art, through the ages.
Here is a still life of fish, eels, and fishing nets, by Johannes Fabritius. ( 17 )
Lesson Summary
- The general traits of fish help adapt them for living in an aquatic environment, mostly
for swimming, and also for extracting oxygen. - Fish are typically ectothermic, although some show warm-blooded adaptations.
- Jawless fish, the Agnatha, also have some other common features.
- Fish with jaws comprise both the cartilaginous fish and the bony fish.
- The cartilaginous fishes, or Chondrichthyes, include the sharks, rays, skates and chi-
maera. - The bony fish, or Osteichthyes, is the largest group of vertebrates in existence today
and have certain traits in common. - Fish are important economically, recreationally and culturally.
Review Questions
- What are the general traits of fish?
- What are some exceptions to the general traits of fish?
- Mudskippers are an example of a fish species that must absorb oxygen across the skin,
instead of via gills, since they spend much of their time out of water. Describe an
environmental situation in which air breathing would be of great use to a fish species. - What are the characteristics of jawless fish?
- What is one structure only found in cartilaginous fishes and what is its function?
- What are some reasons why it would be an advantage for fish to be endothermic?