Class Agnatha (Agantha – “Without jaws”) - Jawless Fish

        Examples: ____________________ & ____________________

        Evolved _____ million years ago (1st fish to appear in the seas, 1st vertebrates)

        Have ________________________________________ covering their bodies

        _____________ & ________________ first evolved in this fish

        Do not have a well-developed ______________________________________

        Major supportive structure in adult jawless fish - ________________________

        Gas Exchange (breathing):




        Key Features:




        Most are __________________



Feeding Mechanism:








Feeding Mechanism:





Evolution of Jaws

Jaws evolved from gill arches that support the pharynx in Agnathans: (fig 27-4)






Class Acanthidii (Acanthodians = “Spiny Fishes”)  - earliest ____________ fish

        Evolved ______ million years ago

        Key features:





        Currently _____________________



Class Placodermi (Placoderms = “Plate skin”)

        Evolved _____ million years ago

        Key features:




        Currently ______________________



Class Chondrichthyes (Chondrichthyes = “Cartilage fish”) Sharks, skates, rays

        Evolved _____ million years ago

        ______________________________________________ make the skin rough like sand paper

        Key features:






        Gas Exchange:





        Advantages of this method of Gas Exchange:




Shark’s Feeding Mechanism

        Large sharks, rays & whales feed on ______________________.

        MOST sharks are _______________________ (they eat meat).

        3 well-developed sense that allow sharks & rays to detect their prey:






Reproduction in Chondricthyes

        Most sharks have ____________________ fertilization: male fishes’ pelvic fins are modified into a pair of claspers used to transfer sperm to the female during mating. Eggs are retained in the body until they hatch, and young sharks are born alive.

        Skates, rays & some sharks have ____________________ fertilization: females lay eggs, fertilized eggs are housed in a leathery case



Class Osteichthyes (Osteichthyes = “Bone fish) - Bony Fish

        Evolved ______ million years ago

        Gills are housed in _________________________ on each side of the head, and are covered by a hard plate called an ________________________

        Key features:









Reproduction in Bony Fish

        _______________________________________________ - Eggs & sperm are released into water or into a nest

        Few species, such as guppies, have _________________________________


2 Major Groups of Bony Fish:



Key Features:






Key features




          Lungfishes – (Australia, S. America, Africa). Ancestors of Amphibians




          Coelacanth – All extinct except one species in East Coast of Africa



Class Amphibia (Amphibian = “double life”) Frogs, toads, salamanders, & wormlike, legless caecilians

        Evolved ______ million years ago

        Adapted to Life on Land: 



Gas Exchange through LUNGS & thin, moist SKIN 


Double-loop circulatory system (pumps both oxygenated & deoxygenated blood)


Fishes’ circulatory system only pumps _____________________ blood to the heart. _____________________ blood flows slowly through the capillaries to the rest of the body.


Blood is pumped at a _____________________________ and _______________  __________________ in ______________________. There is one problem:






Amphibians are confined to a moist environment on land

        Their SKIN is not resistant to _________________________

        Method of ______________________ requires moisture:


Frogs & Toads – __________________________________: Male grabs female, holds onto her, they release eggs & sperm simultaneously. (Eggs & sperm will dry out on land)


Salamanders - ___________________________________: Male attracts female with complex courtship behaviors & deposits a packet of sperm on ground or in water. Female draws sperm packet into reproductive opening, and later deposits ___________________________ in ______________________ or ___________________________________.



Frogs & Toads undergo _____________________________, or changes that occur when a tadpole becomes a frog. Changes that occur include:

* gills -> lungs

* limbs develop

* tail disappears

* feeding habits change (Herbivore tadpole -> Carnivorous frog)



* Larvae retain external gills until the time of metamorphosis

* Larvae resemble parents

* Larvae & Adults are Carnivorous



Orders of Amphibians

Gymniophiona (Gymniophiona = “naked” & “snakelike”)  Caecilians

        Wormlike body with ___________________

        _________________ or __________________ tail

        Habitat: __________________________________

        Feeding Mechanism:





Anura (Anura = “without a tail”) Frogs, toad

        Habitat: ______________________________________________________


        Key features:




        Larvae = ______________________; Adults = _______________________

        Feeding Mechanism:



        Worldwide distribution


Urodela (Urodela = “visible tail”) Salamanders, newts

        Body has distinct ______________, _______________, & ______________

        Limbs set at _____________________________________ to body

        Most are _____________________________

        Worldwide distribution – except Australia


Amphibians Table

  Gymniophiona Anura Urodela
Head, Trunk & Tail?



Cartilage Fish vs. Bony Fish Table

Features Cartilage Fish Bony Fish
Skeleton made of
Skin covered with
Has gills?
Has operculum?
Has swim bladder?
Has paired fins?
Has lateral line?
Can detect electrical currents?
Type of fertilization


Adaptations in Fish

Structure Type of Fish Function
Slimy Surface
Swin Bladder
Sense of smell


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