Phylum Amphibia

(American bullfrog – (American bullfrog – Rana Rana catesbianacatesbiana))

Froggy Classification

Phylum – ChordataPhylum – Chordata

Sub-phylum – VertebrataSub-phylum – Vertebrata

Class – AmphibiaClass – Amphibia

Super-order – Anura (meaning “without tail”)Super-order – Anura (meaning “without tail”)

Order – Salientia (includes frogs and toads)Order – Salientia (includes frogs and toads)

Family – RonidaeFamily – Ronidae

Genus – Genus – RanaRana

Species - Species - catesbianacatesbiana

The OrdersAmphibia:Amphibia:

1. Anura – examples are frogs & toads1. Anura – examples are frogs & toads 2. Caudata – examples are salamanders & 2. Caudata – examples are salamanders &

newtsnewts 3. Apoda – examples are caecilians3. Apoda – examples are caecilians

Amphibians are significant because they Amphibians are significant because they represent the most primitive vertebrates with represent the most primitive vertebrates with four limbs that maintain a terrestrial niche.four limbs that maintain a terrestrial niche.

3 Examples of the order Anura

There are about 3500 species of frogs and There are about 3500 species of frogs and toads.toads.

Frog:Frog: Habitat – temperate and tropical climates Habitat – temperate and tropical climates

around the worldaround the world Niche – insectivores (eating a diet of Niche – insectivores (eating a diet of

insects) insects)

3 Examples of the order Anura, cont’d Toad:Toad: Characteristics – Characteristics – can secrete poison on can secrete poison on

their skin; appear to have dry, wart-covered their skin; appear to have dry, wart-covered skin.skin.

Habitat & Niche – generally same as frogs; Habitat & Niche – generally same as frogs; perhaps somewhat more terrestrial.perhaps somewhat more terrestrial.

3 Examples of the order Anura, cont’d Salamanders / newts:Salamanders / newts: Characteristics – also have poison glands; Characteristics – also have poison glands;

have tails and largely cartilaginous limbshave tails and largely cartilaginous limbs Habitat – live near water, under moist rocks Habitat – live near water, under moist rocks

and logsand logs Niche – same as frogs and toadsNiche – same as frogs and toads

General Characteristics

Have no nails or clawsHave no nails or claws Minimal number of teethMinimal number of teeth Most have a tongue that is projectile and stickyMost have a tongue that is projectile and sticky Spends first stages of life in water as tadpolesSpends first stages of life in water as tadpoles They go through drastic changes during They go through drastic changes during

development (caused by changes in hormones)development (caused by changes in hormones) Tadpoles are herbivorous while adults are Tadpoles are herbivorous while adults are

carnivorouscarnivorous

General Characteristics Cont’d

They are ectotherms. During extreme They are ectotherms. During extreme environmental conditions they either environmental conditions they either hibernate (winter) or aestivate (summer).hibernate (winter) or aestivate (summer).

Temperature regulation is mainly Temperature regulation is mainly behavioralbehavioral

They breathe through poorly developed They breathe through poorly developed lungs and moist skin.lungs and moist skin.

Amphibians – Systems

Well developed brain attached to the dorsal nerve Well developed brain attached to the dorsal nerve cord.cord.

They contain a well developed muscular system.They contain a well developed muscular system. Sensory receptors located all over the skinSensory receptors located all over the skin Good vision since these animals are mainly vision Good vision since these animals are mainly vision

feeders; that is, they have to use their sight to find feeders; that is, they have to use their sight to find and capture food (think of a frog going after a and capture food (think of a frog going after a fly!)fly!)

Amphibians – Reproduction & Reproductive System

Dioecious – 2 different sexes very similar in structure Dioecious – 2 different sexes very similar in structure (appearance)(appearance)

External fertilization in moist environments. External fertilization in moist environments. Exceptions to the external fertilization are salamanders Exceptions to the external fertilization are salamanders (only about 10% are external). (only about 10% are external).

Jelly-like eggs need to be laid in waterJelly-like eggs need to be laid in water Interactions between internal (largely hormonal) Interactions between internal (largely hormonal)

controls and extrinsic factors determine the timing of controls and extrinsic factors determine the timing of reproductive activities.reproductive activities.

Their offspring develop through a process called Their offspring develop through a process called metamorphosis.metamorphosis.

Vocalization

Sound production is primarily a reproductive function Sound production is primarily a reproductive function of male anurans.of male anurans.

These calls attract females to breeding areas and to These calls attract females to breeding areas and to announce to other males that a given territory is announce to other males that a given territory is occupied.occupied.

These calls may also cause some hormonal changes These calls may also cause some hormonal changes internally to occur, reading the breeding process in internally to occur, reading the breeding process in females.females.

Sounds are caused by air being forced from the lungs Sounds are caused by air being forced from the lungs over the vocal cords and cartilages of the larynx, over the vocal cords and cartilages of the larynx, causing them to vibrate.causing them to vibrate.

Our Dissection Froggy

The American bullfrog – The American bullfrog – Rana catesbianaRana catesbiana Typically the specimens are adult male and egg-Typically the specimens are adult male and egg-

bearing females, measuring about 7 inches from the bearing females, measuring about 7 inches from the tips of their snouts to the ends of the trunks. Their tips of their snouts to the ends of the trunks. Their long hind legs, when extended, add another 8 inches long hind legs, when extended, add another 8 inches to their total length of 15 inches.to their total length of 15 inches.

Arteries are injected with RED latex, and veins with Arteries are injected with RED latex, and veins with BLUE or YELLOW latex.BLUE or YELLOW latex.

Frogs shown good organization of systems, along with Frogs shown good organization of systems, along with a relatively complete muscular and skeletal system.a relatively complete muscular and skeletal system.

Special Amphibian Facts Amphibians have a “double Amphibians have a “double

life” because they spend life” because they spend half their life in water and half their life in water and half on land.half on land.

In PA waters, the presence In PA waters, the presence of tadpoles and frogs show of tadpoles and frogs show signs of good environment signs of good environment health. health.