Download Amphibians

Amphibians
Amphibian Characteristics
• Vertebrates (backbone)
• Ectothermic (cold-blooded)
– Must absorb heat from external sources
– When environment becomes too hot or too cold,
many amphibians become dormant (inactive or at
rest) by burrowing in the mud.
Frog Life Cycle
• Metamorphosis
– All amphibians begin life in water
• Most amphibian eggs are fertilized externally
• Eggs do not have shells
Frog Life Cycle
– Fertilized eggs hatch into tadpoles (larval
stage)
• Tadpoles have fins, gills, and a 2-chambered heart
– Tadpoles develop into adults
• Develop legs, lungs, and a 3-chambered heart
Respiration
• Respiration:
– Tadpoles obtain
oxygen from water
that passes over
gills
Respiration
– Adults have lungs
so that they can
exchange gases
with the air
– Adults also
exchange gases
through their thin,
moist skin
Circulation
• Circulation:
– Tadpole – 2-chambered heart and a single
loop of vessels
– Adult – 3-chambered heart and two loops of
vessels (needed for life on land)
Circulation
Types of Amphibians
– Order Anura – frogs and toads
• Do not have tails; feed on insects and worms; have
jaws and teeth; frogs have long legs and smooth
skin; toads have bumpy skin and short legs
pickerel frog
American toad
Types of Amphibians
– Order Caudata – salamanders
• Long, slender body with neck and tail; smooth,
moist skin and no claws; some live in water, others
in damp places; hatch from eggs; adults are
carnivorous
hellbender
spotted salamander
Types of Amphibians
– Caecilians
• Burrow into the ground; no limbs; short or no tail;
live in warm, tropical climates; usually blind; eat
earthworms; internal fertilization
Frog Reproduction