Amphibians

Classification Kingdom:

Animalia

Phylum: Chordata Subphylum

Vertebrates

Class: Amphibians

Examples- frogs, toads,

salamanders newts

The Link Amphibians are the

link between aquatic fish & terrestrial animals. Amphibians -> Reptiles

Have adaptations to move habitat from water to land

“Amphibian” means “double life”

Aquatic Ties Larvae

Gills Tails Algae eaters

Herbivores Moist skin

Will suffocate if can’t get rid of CO2

and receive O2

Adult Must lay eggs in H2O

Lack outer shell

Costa Rica-Tree Frog Eggs

Terrestrial Ties Adults

Lungs + Moist skin Legs Carnivores

Insects/other amphibians

More efficient heart

Evolution of an Amphibian

360 million years ago Evolved from lobed-

fin fish Bones in pectoral

(forearms) and pelvic fins (hind legs)

Homologous structures Leg bones-stronger

To support the body’s weight

Evolution of an Amphibian

1. Formation of rib cage protects internal organs

Evolution of an Amphibian

2. Lateral line (vibrations in H2O) evolved into Tympanic membrane (vibrations in air)

Evolution of an Amphibian

3. Eyelids & nictitating membrane Act like goggles for protection keep moisture in

Evolution of an Amphibian

4. Nares-detect air borne scents

5. 1st amphibians on earth were large Due to no competition for

foodAs the # of vertebrates on land went up/there was more competition for food , the smaller ones were the ones to survive

Traits of Amphibians

1. Metamorphosis-Meta = manyMorphosis = change form

Aquatic larvae goes through many changes to become a terrestrial adult

Traits of Amphibians

2. Cold-blooded-ectotherms Use environment to regulate

temperature

Traits of Amphibians

3. External fertilization- Need H2O Jelly-coated Eggs No shells

Traits of Amphibians

4. Feet, if present, lack claws Often webbed

Traits of Amphibians

5. Moist porous skin Cutaneous Respiration

In O2 & H2O thru skin Out CO2 & H2O thru skin

Traits of Amphibians

6. Also respire or also breath thru a pair of internal lungs.

Number of species 4500 different

species of amphibians

Order Anura

Means: tailless 3800 species of

frogs & toads Lay jelly-coated

eggs in H2O Tadpoles-

compact bodies Tongue sticky,

long

Let us watch…..

Anura Frog

Smooth skin Jump= powerful

hind legs Live near H2O

Toad Rough bumpy skin Poisonous glands Only walk Live on land

(moist)

Poisonous Cane Toad

Introduced as “pest management” for beetles and other insects but know are breeding out of control and due to poisonous skin are killing farm animals and pets that eat them.

Urodela

400 different species= salamanders& newts Long tails Elongated bodies Moist skin 4 limbs Lives in moist area Lay eggs in H2O Worldwide- except

Australia

Apoda or Gymnophiona “legless”

amphibians 160 species Ex/Caecilians 12” long Resembles a snake Lives in the tropics

in dirt/soil Eat Insects Rarely seen~

borrows in soil

Caecilian:

Life of a Frog (Metamorphosis)

Larvae (fish-like) Gills Fin-like tail 2 chamber heart like

a fish Closed system 1 loop Primarily herbivores

Life of a Frog (Metamorphosis)

Adult Lungs Legs Closed system 3 chamber heart 2 loop system Primarily carnivores

External covering/moist skin

-two jobs1. Respiration

(cutaneous) thin, moist skin-if

skin dries suffocation b/c increase CO2

Most active @ night-cooler, more moisture

Mucus glands- more moisture

2. Protection Some poisonous Most secrete a

foul tasting substance

Skin-camouflaging Blends in with environment