CHAPTER 27 – FISH & AMPHIBIANS 

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

·        Examples: ____________________ & ____________________

·        Evolved _____ million years ago (1^st fish to appear in the seas, 1^st 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 __________________

Lamprey

Feeding Mechanism:

Hagfish

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: 

Legs

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 ___________________________________.

·        Development

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)

Salamanders

* 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

Cartilage Fish vs. Bony Fish Table

Adaptations in Fish