Chapter 3Chapter 3

Section 3Section 3

AmphibiansAmphibians

Amphibian:Amphibian:– Ectothermic vertebrate that spends its Ectothermic vertebrate that spends its

early life in water early life in water

Amphibians spend their adulthood on Amphibians spend their adulthood on landland

They return to water to reproduceThey return to water to reproduce

AmphibiansAmphibians

Reproduction:Reproduction:– They lay eggs in the waterThey lay eggs in the water

– Eggs hatch into larvae that swim Eggs hatch into larvae that swim Have gills to obtain oxygenHave gills to obtain oxygen

– Undergo metamorphosisUndergo metamorphosis

– As adults they have lungsAs adults they have lungs Obtain oxygen and get rid of carbon dioxide through Obtain oxygen and get rid of carbon dioxide through

their thin, moist skintheir thin, moist skin

AmphibiansAmphibians

http://static.ddmcdn.com/gif/frog-life-cycle.gif

CirculationCirculation

Tadpole circulatory systemTadpole circulatory system– Single loop while they have gillsSingle loop while they have gills– Like fishLike fish

Adult circulatory systemAdult circulatory system– Double loop when they have lungsDouble loop when they have lungs– 1st loop: Blood flows from heart to lungs and 1st loop: Blood flows from heart to lungs and

skin to pick up oxygenskin to pick up oxygen– 22ndnd loop: Blood flows to the rest of the body to loop: Blood flows to the rest of the body to

deliver oxygen-rich blooddeliver oxygen-rich blood

CirculationCirculation

http://universe-review.ca/I10-82-circulatory.jpg

CirculationCirculation

Chambers of the heart:Chambers of the heart:– Atria: two upper chambers of the heart Atria: two upper chambers of the heart

that receive bloodthat receive blood 1 receives oxygen-rich blood from the lungs1 receives oxygen-rich blood from the lungs The other receives oxygen-poor blood from The other receives oxygen-poor blood from

the bodythe body

– Ventricle: lower chamber of the heart Ventricle: lower chamber of the heart that pumps blood out to the lungs and that pumps blood out to the lungs and the bodythe body Oxygen-rich and oxygen-poor blood mix hereOxygen-rich and oxygen-poor blood mix here

CirculationCirculation

http://www.coolcompanions.com.au/wp-content/uploads/2010/06/The-three-chambered-frog-heart-mixes.jpg

CirculationCirculation

http://www.biologycorner.com/resources/frog-heart.gif

AmphibiansAmphibians

Reproduction:Reproduction:– Male frogs or “peepers” using a call to Male frogs or “peepers” using a call to

attract matesattract mates

– Most frogs and toads use external Most frogs and toads use external reproductionreproduction Female releases eggs that are fertilized by Female releases eggs that are fertilized by

spermsperm

– Salamanders use internal reproductionSalamanders use internal reproduction Eggs are fertilized before they are laidEggs are fertilized before they are laid

AmphibiansAmphibians

Reproduction:Reproduction:– Eggs are Eggs are

coated with a coated with a clear jelly to clear jelly to remain moistremain moist

– Tiny embryo Tiny embryo developsdevelops

– Few days later Few days later larvae wriggle larvae wriggle out of the jellyout of the jelly

AmphibiansAmphibians

AmphibiansAmphibians

Care:Care:– Most young are on their own right awayMost young are on their own right away

– Exceptions:Exceptions: South American River ToadSouth American River Toad

– Male presses the eggs into the female’s backMale presses the eggs into the female’s back

MetamorphosisMetamorphosis

MetamorphosisMetamorphosis1.1. Hind legs appearHind legs appear2.2. Changes in the skeleton, circulatory system, Changes in the skeleton, circulatory system,

and digestive systemand digestive system3.3. Front legs appearFront legs appear4.4. Loses its gills and starts to breathe with lungsLoses its gills and starts to breathe with lungs

Frogs and toad adults look different than Frogs and toad adults look different than larvaelarvae

Salamander larvae resemble the adultSalamander larvae resemble the adult

MetamorphosisMetamorphosis

http://dj003.k12.sd.us/SCHOOL%20NOTES/029%20Life%20cycle%20of%20a%20frog.jpg

MetamorphosisMetamorphosis

Moving on LandMoving on Land

Adaptations to life on land:Adaptations to life on land:– Strong skeleton Strong skeleton – Muscular limbsMuscular limbs

11stst vertebrates to have legs vertebrates to have legs

– Eyes Eyes Transparent membrane to keep them from Transparent membrane to keep them from

drying outdrying out

– EyelidsEyelids

Moving on LandMoving on Land

Moving on LandMoving on Land

Frogs and ToadsFrogs and Toads

AdaptationsAdaptations– Powerful hind-leg musclesPowerful hind-leg muscles

– Skeleton to absorb shockSkeleton to absorb shock

– Webbed feet and long toes – BullfrogsWebbed feet and long toes – Bullfrogs

– Adhesive suckers – Tree frogsAdhesive suckers – Tree frogs

Frogs and ToadsFrogs and Toads

Distinguish a frog from a toad:Distinguish a frog from a toad:– Frog skin is smooth and moistFrog skin is smooth and moist

– Toad skin is dry and bumpyToad skin is dry and bumpy

– Toads have lumps behind their eyes Toads have lumps behind their eyes Contain a poisonous liquid when attackedContain a poisonous liquid when attacked

Frog vs. ToadFrog vs. Toad

Frogs and ToadsFrogs and Toads

What do they eat?What do they eat?– TadpolesTadpoles

Herbivore Herbivore

– Adult Frogs and ToadsAdult Frogs and Toads Predators that eat insects or small animalsPredators that eat insects or small animals Camouflaged to blend into their Camouflaged to blend into their

environmentenvironment– Brownish green to blend into pondsBrownish green to blend into ponds

SalamandersSalamanders

Keep their tails as adultsKeep their tails as adults Legs are not adapted for jumpingLegs are not adapted for jumping Some live in water their whole life Some live in water their whole life

while other live on landwhile other live on land– Some do not have lungsSome do not have lungs– They obtain oxygen through their moist They obtain oxygen through their moist

skinskin– Do not return to water to reproduceDo not return to water to reproduce– Lay their eggs on land in moist placesLay their eggs on land in moist places

SalamandersSalamanders

Amphibians in DangerAmphibians in Danger

In danger due to habitat destructionIn danger due to habitat destruction– Swamps are filled inSwamps are filled in– Forest is cutForest is cut– Moist area becomes dryMoist area becomes dry

Environmental poisonsEnvironmental poisons– Insecticides and other chemicals pollute Insecticides and other chemicals pollute

waterwater