Transcript Fishes and Amphibians

Vertebrates: Part I
Fishes &
Amphibians
Phylum Chordata
Chordates: includes all the vertebrates
 Have 3 common characteristics:

– Nerve Cord: hollow tube that hold nervous
tissue
– Notochord: rod that runs down the back for
support (in higher vertebrates it is replaced
with the vertebral column)
– Throat with gill slits: used for breathing (in
higher vertebrates these turn into the
trachea)
Phylum Chordata

There are 5 groups in the phylum
Chordata we will study
– 3 groups are cold blooded: no internal
temp regulation. They take on the temp of
their surroundings
– 2 groups are warmblooded: maintain a
constant body temp
Phylum Chordata
 The
5 Groups:
–Fish: cold blooded
–Amphibians: cold blooded
–Birds: warm blooded
–Reptiles: cold blooded
–Mammals: warm blooded
Fishes
Live
in freshwater or
saltwater
Bone or cartilage protects
brain & spinal cord
Gills for respiration
Mostly external fertilization
Fishes
3 Characteristics:
– Scales
– Fins
– Throat with gill slits
 Closed Circulatory System
 Well developed nervous system
 Keen sense of smell and taste

Classes of Fishes
 Jawless
Fish
–Lamprey, Hagfish
 Cartilaginous
Fish
–Sharks, rays, and Skates
 Bony
Fish
–Most common fish
Jawless Fish
 Have
no bone,
only cartilage
 Flexible
 Use teeth and
their tongue to
eat
Cartilaginous Fish
 No
bones, only
cartilage
 Toothlike scales
 Sharks can
have 1000’s of
teeth in up to 20
rows
Cartilaginous Fish
 Skates
and
Rays use
poison or
electric volts to
stun their prey
Bony Fish
Have bony
skeleton
 Most common
type of fish
 Many different
species
 Have paired fins

Bony Fish
 Swim
in Schools
 Swim Bladders:
gas filled sac that
gives fish
buoyancy
Fish Structure
Amphibians
(Amphi- double)
 Cold Blooded
 Most have metamorphosis
 Breathe with gills when
immature and lungs and skin
when they are adult
 Use both internal and external
fertilization
WHY THEY LIVE ON
LAND AND WATER
Drying
out: skin needs to be
moist to breathe
Respiration: use gills as a
baby
Reproduction: eggs don’t
have hard shell
AMPHIBIANS
2
Groups
–frogs, toads
–salamanders, newts
FROGS AND TOADS
Hibernate during winter
 Skin:

– Frogs: smooth and moist
– Toads: warty and dry
Large hind legs for jumping: helps them
to escape predators
 Lay their eggs in water

Frog Life Cycle
SALAMANDER & NEWTS

VERY SIMILIAR TO FROGS EXCEPT:
– No large back legs: cant jump
– Do not hibernate

Lay their eggs in water
SALAMANDERS & NEWTS
Clawless
 Have short smooth moist bodies
 Long tail.
 They do not have scales.
