Phylum Amphibia
(American bullfrog – Rana
catesbiana)
Froggy Classification
Phylum – Chordata
Sub-phylum – Vertebrata
Class – Amphibia
Super-order – Anura (meaning “without tail”)
Order – Salientia (includes frogs and toads)
Family – Ronidae
Genus – Rana
Species - catesbiana
The Orders
Amphibia:
1. Anura – examples are frogs & toads
2. Caudata – examples are salamanders &
newts
3. Apoda – examples are caecilians
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Amphibians are significant because they
represent the most primitive vertebrates with
four limbs that maintain a terrestrial niche.
3 Examples of the order Anura
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There are about 3500 species of frogs and
toads.
Frog:
 Habitat – temperate and tropical climates
around the world
 Niche – insectivores (eating a diet of
insects)
3 Examples of the order Anura,
cont’d
Toad:
 Characteristics – can secrete poison on
their skin; appear to have dry, wart-covered
skin.
 Habitat & Niche – generally same as frogs;
perhaps somewhat more terrestrial.
3 Examples of the order Anura,
cont’d
Salamanders / newts:
 Characteristics – also have poison glands;
have tails and largely cartilaginous limbs
 Habitat – live near water, under moist rocks
and logs
 Niche – same as frogs and toads
General Characteristics
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Have no nails or claws
Minimal number of teeth
Most have a tongue that is projectile and sticky
Spends first stages of life in water as tadpoles
They go through drastic changes during
development (caused by changes in hormones)
Tadpoles are herbivorous while adults are
carnivorous
General Characteristics Cont’d
They are ectotherms. During extreme
environmental conditions they either
hibernate (winter) or aestivate (summer).
 Temperature regulation is mainly behavioral
 They breathe through poorly developed
lungs and moist skin.
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Amphibians – Systems
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Well developed brain attached to the dorsal nerve
cord.
They contain a well developed muscular system.
Sensory receptors located all over the skin
Good vision since these animals are mainly vision
feeders; that is, they have to use their sight to find
and capture food (think of a frog going after a
fly!)
Amphibians – Reproduction &
Reproductive System
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Dioecious – 2 different sexes very similar in structure
(appearance)
External fertilization in moist environments.
Exceptions to the external fertilization are salamanders
(only about 10% are external).
Jelly-like eggs need to be laid in water
Interactions between internal (largely hormonal)
controls and extrinsic factors determine the timing of
reproductive activities.
Their offspring develop through a process called
metamorphosis.
Vocalization
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Sound production is primarily a reproductive function
of male anurans.
These calls attract females to breeding areas and to
announce to other males that a given territory is
occupied.
These calls may also cause some hormonal changes
internally to occur, reading the breeding process in
females.
Sounds are caused by air being forced from the lungs
over the vocal cords and cartilages of the larynx,
causing them to vibrate.
Our Dissection Froggy
The American bullfrog – Rana catesbiana
 Typically the specimens are adult male and eggbearing females, measuring about 7 inches from the
tips of their snouts to the ends of the trunks. Their
long hind legs, when extended, add another 8 inches to
their total length of 15 inches.
 Arteries are injected with RED latex, and veins with
BLUE or YELLOW latex.
 Frogs shown good organization of systems, along with
a relatively complete muscular and skeletal system.
Special Amphibian Facts
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Amphibians have a “double
life” because they spend
half their life in water and
half on land.
In PA waters, the presence
of tadpoles and frogs show
signs of good environment
health.