frogs and toads

Frogs and

Toads

Toads

• Toads have dry, warty skin

• Generally found in drier climates

• Stubby bodies with short hind legs

• Parotid (poison) glands behind the eyes

• Lay eggs in chains

Pelobatidae and ScaphiopodidaeSpadefoot toads

• Burrowing toads• Hardened protrusion on their foot for digging• Very quick metamorphic stage – 2 weeks!• Tadpoles are cannibalistic to speed up

metamorphosis• Native to Europe, W. Asia, and N. Africa

http://asm.wku.edu/froglogger/default.html

Bombinatoridae - Fire-bellied toads

• Brightly colored ventral sides – highly toxic to predators!!

• Aquatic toads• Unken reflex - the animal will

arch its back and limbs to expose the bright belly

• Lay pigmented eggs in ponds• Native to northeastern asia

Bufonidae - The TRUE Toads

• All members of their family possess toad-like characteristics

• Occur on every continent except Australia and Antartica

• Inhabit a variety of environments

• Male toads possess a Bidder’s organ – generally inactive, but become an active ovary!!

http://bioweb.wku.edu/froglogger/

Frogs

• Two bulging eyes• Strong, long, webbed

hind feet designed for jumping and swimming

• Smooth and slimy skin• Lay eggs in clusters

Ascaphus - The Tailed Frogs – Wait a minute…what?!!?

• Mostly aquatic• Tail is an extension of the cloaca –

only found in males• Minimizes sperm loss in turbulent

waters• Use internal fertilization (other

frogs and toads use external)• Primitive frogs – greater number

of vertebrae, lack the ability to vocalize, and possess free ribs

• Found in North America

Dendrobatidae - Poison Dart Frogs

• Arboreal and terrestrial• Native to Central and

South America• Brightly colored bodies

to exhibit toxicity to predators

• Used to tip darts• Piggy-back tadpoles once

they hatch• Exhibit parental care

Medical Application

• Nerve toxins affecting the nervous system and heart activity

• Muscle relaxants, heart stimulants, and appetite supressants

• Skin may be 200 times more potent than morphine!

• One species has enough poison to kill ten men!

Centrolenidae – Really cool Glass Frogs

• Coloration primarily lime green • The internal organs, including the heart, liver,

and gastrointestinal tract are visible through this translucent skin

Hylidae – Tree Frog

• Live in a variety of habitats including semi-aquatic, terrestrial, and arboreal

• Pronounced forward eyes• Adhesive pads on the toes and fingers• Come in all different colors!!

http://bioweb.wku.edu/froglogger/

Ranidae – The TRUE frogs• The widest distribution of any

frog family• Occurs in all continents except

Antarctica• Large, powerful legs and

extensive webbing on their feet• Many are aquatic and most live

close to the water• Some are arboreal and

burrowers• Occur in all sizes – largest frog in

the world is the Goliath frog

http://asm.wku.edu/froglogger/default.html

Why are frog species important?

• Frogs are keystone species. – A keystone species plays a critical role in

maintaining the structure of an ecological community.

– Because they are sensitive to changes in the environment, they may suffer from huge increases in mortality.

• Can help to determine the overall health of an ecosystem.

Why are frog species important?

• Invaluable tool for studying body systems.– Dissections on frogs can be used to compare to

other vertebrates• Important source of food– Frog legs – taste like chicken?

• Medicinal purposes– Poison dart frogs