Transcript Amphibians PPT

Amphibian
Diversity
Amphibians
• Term “amphibian” means “double life.”
• During their life cycle, they live both in the
water and on the land
– When immature, they are fishlike and breathe
through gills
– As adults, they live on land and breathe through
lungs and moist skin
Main Characteristics
• 3 main groups:
– Frogs and toads - Anurans
– Salamanders and newts – Urodeles
– Legless amphibians - Caecilians
• Ectothermic – Cold-blooded vertebrates whose body
temperatures adjust with the outside
environment
Main Characteristics cont.
• Quadrupeds
• Bony skeleton
• Double Circulation- sinuous venosus, two
atria, ventricle
• Tympanic membrane- eardrum
• Nictitating membrane- moves up over eye
• Primarily oviparous
Vs.
Frogs have:
smooth or slimy skin
strong, long legs and
webbed hind feet
two bulging eyes
lay eggs in clusters
small teeth in upper
jaw
Toads have:
warty and dry skin
stubby bodies with short
hind legs
parotid glands behind eyes
lay eggs in long chains
no teeth
Salamanders & Newts
• Have long bodies, tails, and short legs
• Only 440 species in the world
• Generally, the adults live on land and return
to the water only for breeding
Metamorphosis
Main Characteristics,cont.
Adult amphibians live in moist areas. Why?
– In addition to breathing through lungs, they
also breathe through their skin
– They have thin, semi-permeable skin that needs
to remain moist
– Their eggs lack hard outer shells and must be
deposited or laid in water
Where do they go in winter?
• Most frogs bury themselves in the muddy floor of a lake or
pond during the winter; whereas toads tend to dig down
into the ground below the frost line.
• Hibernation: a winter sleep during which time the animal
can live on food stored in its body. The oxygen it needs
can pass through its skin.
• A few species actually freeze solid during the winter.
– Their body creates an “anti-freeze” that saturates their cells so they
don’t freeze, although their breathing and heart stops
Amphibian Circulation
How does blood not get
Mixed?
1- spiral valve
2- asynchronous contractions of atria
3- different blood pressures between
Pulmonary and systemic circuits
Frogs and Toads
92 species
in USA
4,000+ species
in the world
External Characteristics
Internal Characteristics
Idaho’s Frogs and Toads
Tailed Frog
Western Toad
Great Basin Spade-foot toad
Pacific Tree Frog