Fish, reptiles, birds and mammals Flashcards
What is a fish?
vertebrate
almost all species aquatic
Distinguishing features:
- fins
- scales
- gills
What is the importance of fish?
Evolutionary- first lineage of vertebrates
Most diverse extant vertebrates (35,000 spp)
Food- cheap and widely available
Commerical- fisheries and aquaculture
Other products health, industry
Recreation and tourism
What is the external anatomy of fish?
Scales
Lateral line
Fins- median and paired
Gills- Elasmobranchs: 5-7 pairs, individual slits
- Bony fishes (teleosts): 4 pairs, operculum (gill cover)
What are the gill structures?
Elasmobranch
Osteichthyes
What is the pseudobranch?
Is a gill like structure found in most fish species that is attached to the inside of the operculum
Rich in carbomic anhydrase- acidifies blood and releases oxygen in blood to eye
What is rete mirabile?
In fish, the rete mirabile is a critical adaptation used to supply oxygen to tissues like the eye and the swim bladder, where high oxygen concentrations are essential
Counter-current exchange
In eye, this maintains high blood acid in vessels supplying eye (carbonic acid)
Enhances oxygen unloading to supply eye by direct diffusion
What sub phylum exist within the phylum Chordata?
Sub-phylum Urochordata
Sub-phylum Cephalochordata
Sub-phylum Vertebrata
What are the ancient lineage representatives?
Class Sarcopterygii:
- Coelacant- sub class Coelocanthamorpha
- Lungfishes- sub class (infra-class) Dipnoi
Class Actinopterygii
Bichirs- sub class Cladistia
Gars- sub class Neopterygii, order Semionotiformes
Bowfin- sub-class Neopterygii, order Amiiformes
What are the chondrichthyes?
the cartilaginous fishes
What classes exist in the superclass Ganthostomata?
Super class Ganthostomata: jawed fishes
Class Chondrichthyes: cartilaginous fishes
Sub class Holocephali: chimaeras
Sub class Elasmobranchii (plate gills): sharks, skates, rays
How are the sub class Holocephali described?
Single gill flap covering 4 internal gill openings
Male intromittent organs (claspers)
Males have frontal (tentaculum) on forehead in some species
Reproduce via shelled eggs
First dorsal fin erectable (with poison spine)
Oily liver
What super order exists in the sub class Elasmobranchii?
Super order (cohort) Euselachii
8 orders of sharks
1 (or 5) orders of rays
What are the characteristics of the sharks and allies?
5-7 external gill slits
Spiracular opening
Dorsal fins not collapsible
Male intromittent organs (claspers)
Placoid, mushroom-shaped scales
Oily liver
No gas bladder
Varied reproduction (eggs, ovoviviparity, viviparty)
What are the other characteristics of the sharks and rays?
5 gill slits
Flattened teeth
Spiracles
All lay eggs
Dorsal fins reduced/absent
What are the Osteichthyes?
The bony fishes