SI 9/1/09
Fish Worksheet
1. Earliest group of fish – jawless, no paired fins, no vertebral column, this superclass is not a true taxonomic group.
- Agnatha
2. What are the two extant classes of jawless fish.
- Myxini and Cephalaspidomorphi
3. This fish is eel-like, jawless, has slime glands, has no stomach, is a decomposer and deep marine species.
- Hagfish or Myxini
- Follow up question!! Are these true vertebrates? NO
4. This fish is jawless, scaleless, has no paired fins, and filter feed as larvae; adults either do not feed or feed via parasitic rasping into fish.
- Cephalaspidomorphi or lampreys
5. There are many forms of this jawless fish, which are now extinct, but they are grouped under one name. They have a covering of dermal bone forming armored carapace (sometimes with smaller plates or scales). What is the group name?
- Ostracoderms
6. This superclass evolved a hinged jaw and paired limbs.
- Gnathostomata
7. Osctracoderms, which are now extinct, appeared in this era, 490 – 350 MYA.
- Ordovician – Devonian
8. This adds stability during locomotion and is the source of tetrapod limbs.
- Paired Fins
9. These are the two extinct classes of Gnathostomata.
- Acanthodia and Placodermi
10. This class includes animals with cartilaginous skeleton, heterocercal tail, no swim bladder, and, sharks, skates, and rays.
- Chrondrichthyes (cartilaginous fish)
11. This class lived during the second half of the Paleozoic and includes characteristics such as toothed jaws, heterocercal tails, a vertebral column, and multiple sets of paired fins.
- Acanthodia
12. Half of the living vertebrates belong to this class.
- Osteichthyes
13. This is a pouch from the esophagus with air volume regulated for buoyancy. It does not appear until Class Osteichthyes.
- Swim bladder
14. This subclass includes ray-finned fishes and the infraclasses: Chondrostei and Neopterygii.
- Actinopterygii
15. This class is the oldest group of osteichthyes, are lobe finned, and a precursor to tetrapods.
- Sarcopterygii
16. This order of Sarcopterygii were common during the Devonian and are termed a ‘living fossil’
- Coelocanthiformes
17. Fish in this order are the closest living relatives of tetrapods and fall under the class Sarcopterygii.
- Ceratodontomorpha
18. Ceratodontomorpha (lung fish) form a cocoon during dry periods and do this in mud.
- Aestivate
19. List and describe the 3 types of fish scales:
Placoid-from mesoderm/composed dentine, ganoid-composed of bone. Cycloid/ctenoid- outer layer of bone/thin layer connective tissue
20. What caused the predatory lifestyle to begin?
Hinged jaws….wider prey types
21. What fish class was the precursor to tetrapods?
- Rhipidistians(order coelocanthiforms)
22. When was the age of the fishes?
- Devonian