Agnathans and fish Flashcards
what are some characteristics of the subphylum vertebrata
1) cranium to protect brain
2) vertebral column
3) tripartite brain
what is the name of the jawless fish vs jawed fish
agnatha = jawless
gnathostomata = jawed
what are the classes of the agnathous
1) myxini
2) pteraspidomorphi
3) petromyzontida
which class of agnathous is extinct
pteraspidomorphi
what are some features the agnatha
- no jaw
- true teeth are absent
- paired fins are absent
- single nostril
- scaleless
- cartilage skeleton
what are some characteristics of hagfish (myxini)
- elongated eel-like bodies
- marine deep water
- produce large amount of slime
what are some characteristics of the class petromyzontida
- fresh and saltwater
- tooth funnel- like sucking mouth
- larvae called ammocoetes
what are some characteristics of gnathostomes
- jaw
- teeth
- paired appendages
- modification to ear
what is a heterocercal tail
when the upper lobe of the tail is larger than the lower lobe
how do shark and rays identify pray
large olfactory organs
- mechanoreceptors in the lateral line sense low frequency vibrations from far away then vision at close range
what are some characteristics of chondrichthyes fertalisation
have internal fertilization
what are ovoviviparous species
when the embryo is retained in the uterus nourished by yolk = no placenta
what ate viviparous species
when the embryo receives nourishment through a placenta
what are the three subclasses of actinopterygii
1) chondrosteans
2) neopterygians
3) teleosts
what is the name of the muscles which are used by fish for locomotion
myomeres
what are the 5 types of locomotion in fishes based on their body movements
1) anguilliform
2) sub-carangiform
3) carangiform
4) thunniform
5) ostraciiform
what is the difference between anguilliform and ostraciiform fish
1) the whole body moves in a sinusoidal wave
2) only the tail fin itself moves whilst the body remains still
how do more primitive fish remain buoyant
a pneymatic duct which connects to the swim bladder and esophagus
what are catadromous fish
enter the ocean as adults migrating from fresh water to their spwaning area where they die before larvae make way back to streams
what are anadromous fish
fish which spend their lives only in the ocean and return to fresh water to spawn
