AmphibiansAmphibians

Characteristics of Characteristics of AmphibiansAmphibians

VertebrateVertebrate Lives in water as larva; land as adult Lives in water as larva; land as adult

(some exceptions)(some exceptions) Breathes with lungs as adultBreathes with lungs as adult Moist skin with mucus glandsMoist skin with mucus glands No scales and clawsNo scales and claws

Evolution of AmphibiansEvolution of Amphibians

First amphibians during Devonian PeriodFirst amphibians during Devonian Period Transitioned from water to landTransitioned from water to land

Breathe airBreathe air Protect eggs and themselves from drying outProtect eggs and themselves from drying out Support against the pull of gravitySupport against the pull of gravity

Evolution Continued…Evolution Continued…

Adaptations evolved to live at least part Adaptations evolved to live at least part of life out of water.of life out of water. Stronger bones in limbs and limb girdles; Stronger bones in limbs and limb girdles;

more efficient movementmore efficient movement Lungs and breathing tubesLungs and breathing tubes SternumSternum or breastbone for shield and or breastbone for shield and

support.support.

Pelvic Girdle

Lungs

Leg Bones: The legs of a land vertebrate must be strong enough to hold its weight.

Skin: The skin and the lining of the mouth cavity of many adult amphibians are thin and richly supplied with blood vessels. Watery mucus is secreted by glands in the skin.

As AdultsAs Adults lungs are richly supplied with lungs are richly supplied with blood vessels and folds that increase surface blood vessels and folds that increase surface areaarea

Lungs

Class AmphibiaClass Amphibia

Includes frogs, toads, salamanders, and Includes frogs, toads, salamanders, and caecilians.caecilians.

Small and diverse classSmall and diverse class Due to extinction of most amphibians during Due to extinction of most amphibians during

Permian Period (climate changes)Permian Period (climate changes) Low, swampy habitats disappearedLow, swampy habitats disappeared

FeedingFeeding

TadpolesTadpoles Filter feeders or herbivores (algae)Filter feeders or herbivores (algae) Intestine breaks down hard plant materialIntestine breaks down hard plant material

AdultsAdults CarnivoresCarnivores Sticky tongues to capture insectsSticky tongues to capture insects

RespirationRespiration

Gas exchange through skin and gills Gas exchange through skin and gills (larval stage)(larval stage)

Lungs, skin, and lining of mouth cavity Lungs, skin, and lining of mouth cavity (adult stage)(adult stage)

Lungless amphibians:Lungless amphibians: thin lining of thin lining of mouth cavity and skinmouth cavity and skin

CirculationCirculation

Double loopDouble loop First loopFirst loop

Oxygen-poor blood from heart to lungs and Oxygen-poor blood from heart to lungs and skinskin

Oxygen-rich blood from lungs and skin to left Oxygen-rich blood from lungs and skin to left atriumatrium

Second loopSecond loop Oxygen-rich blood from heart to rest of bodyOxygen-rich blood from heart to rest of body Oxygen-poor blood from body back to heartOxygen-poor blood from body back to heart

Amphibian HeartAmphibian Heart

Three Three separate separate chamberschambers Left atriumLeft atrium Right atriumRight atrium VentricleVentricle

Right atrium Left atrium

Ventricle

To body, lungs and skin

From Body

From Lungs

ExcretionExcretion Kidneys to filter Kidneys to filter

wastes from wastes from bloodblood

Urine excreted; Urine excreted; travels from travels from ureters ureters to to cloaca cloaca to to outside outside or or stored in stored in urinary urinary bladderbladder

Heart

Lung

Kidney

Ureter

Cloaca

Urinary bladder

ReproductionReproduction

Females lay eggs in water; male fertilizes Females lay eggs in water; male fertilizes them externally (most amphibians)them externally (most amphibians)

Internal fertilization (salamanders)Internal fertilization (salamanders) After fertilization; frog eggs encased in After fertilization; frog eggs encased in

sticky, transparent jellysticky, transparent jelly Yolk of egg nourishes embryoYolk of egg nourishes embryo

MovementMovement

Wiggle tails; flattened tails for propulsion Wiggle tails; flattened tails for propulsion (larva)(larva)

Adult salamanders walk or runAdult salamanders walk or run Frogs and toads: well developed hind Frogs and toads: well developed hind

limbs (jump long distances)limbs (jump long distances)

ResponseResponse

Well developed nervous and sensory systemsWell developed nervous and sensory systems Nictitating MembraneNictitating Membrane

Moist and transparentMoist and transparent Located inside regular eyelidLocated inside regular eyelid Can be closed over the eyeCan be closed over the eye

Tympanic MembraneTympanic Membrane Eardrums located on each sideEardrums located on each side

Lateral LineLateral Line Used to detect movement in water Used to detect movement in water

Frog DigestionFrog Digestion

Food enters the mouth Food enters the mouth esophagus esophagus stomach stomach small intestine small intestine large large intestine intestine cloacacloaca Cloaca: Cloaca: muscular cavity where solid waste, muscular cavity where solid waste,

urine, eggs and sperm exit bodyurine, eggs and sperm exit body

Liver, pancreas and gall bladder excrete Liver, pancreas and gall bladder excrete enzymes that aid in digestionenzymes that aid in digestion

Frog Movie

Stomach

Esophagus Mouth

Small intestine

GallbladderLiver

Pancreas

Large intestine (colon)

Cloaca

Frog ReproductionFrog Reproduction

Adults ready to breed in 1 to 2 yearsAdults ready to breed in 1 to 2 years Eggs laid in water (external fertilization)Eggs laid in water (external fertilization) Fertilized eggs Fertilized eggs tadpoles (several days tadpoles (several days

to few weeks)to few weeks) Tadpoles gradually lose tails and gills, Tadpoles gradually lose tails and gills,

grow limbs. grow limbs.

Frog Metamorphosis

Fertilized eggs

Tadpoles

Young Frog

Adult Frog

3 Groups of Amphibians3 Groups of Amphibians

SalamandersSalamanders

Frogs and ToadsFrogs and Toads

CaeciliansCaecilians

SalamandersSalamanders

Long tails and bodiesLong tails and bodies 4 legs4 legs CarnivorousCarnivorous Live in moist woods (adults)Live in moist woods (adults)

Tunnel under rocks and rotting logsTunnel under rocks and rotting logs

Frogs and ToadsFrogs and Toads

Ability to jumpAbility to jump Long legs = lengthy jumps (Frogs)Long legs = lengthy jumps (Frogs) Short legs = short hops (Toads)Short legs = short hops (Toads) Frogs closely tied to waterFrogs closely tied to water Toads closely tied to moist woods Toads closely tied to moist woods

CaeciliansCaecilians

Legless animals that live in water or Legless animals that live in water or burrow in moist soilburrow in moist soil

Feed on small invertebrates (termites)Feed on small invertebrates (termites) Fish-like scales embedded in their skinFish-like scales embedded in their skin

Frog DissectionFrog Dissection

External AnatomyExternal Anatomy

TympanumTympanum

External NaresExternal Nares

Internal NaresInternal Nares

Vomerine TeethVomerine Teeth

TongueTongue

Eustachian TubeEustachian Tube

Maxillary TeethMaxillary Teeth

Dorsal Muscular Dorsal Muscular AnatomyAnatomy

2. Pterygoideus2. Pterygoideus 3. Temporalis3. Temporalis 4. Masseter4. Masseter 5. Depressor 5. Depressor

mandibularismandibularis 6. Trapezius6. Trapezius 11.Latissimus dorsi11.Latissimus dorsi 14.External oblique14.External oblique 17.Gluteus17.Gluteus 18.Piriformis18.Piriformis 20.Vastus externus20.Vastus externus 25.Gracilis minor25.Gracilis minor 26.Gastrocnemius26.Gastrocnemius 28.Semimembranosus28.Semimembranosus 29.Biceps femoris29.Biceps femoris

4.Masseter4.Masseter 5.Depressor 5.Depressor

mandibularismandibularis 6.Dorsalis scapulae 6.Dorsalis scapulae 10.Trapezius10.Trapezius

55.Depressor 55.Depressor mandibularismandibularis

10.Trapezius10.Trapezius

Ventral Muscular Ventral Muscular AnatomyAnatomy

7.Deltoid7.Deltoid 9.Pectoralis major9.Pectoralis major 12.Rectus 12.Rectus

abdominusabdominus 13.Linea alba13.Linea alba 14.External oblique14.External oblique 30.Mylohyoid30.Mylohyoid

77 37.Deltoid37.Deltoid

9.Pectoralis major9.Pectoralis major

13.Linea alba13.Linea alba

20.Rectus femoris20.Rectus femoris

21.Adductor magnus21.Adductor magnus

22.Sartorius22.Sartorius

24.Gracilis major24.Gracilis major

25.Gracilis minor25.Gracilis minor

26.Gastrocnemius26.Gastrocnemius

27.Achilles tendon27.Achilles tendon

30.Mylohyoid30.Mylohyoid

Internal AnatomyInternal Anatomy

CerebellumCerebellum

CerebrumCerebrum

LiverLiver

HeartHeart

2 Atria

1 Ventricle

StomachStomach

Large IntestineLarge Intestine

SpleenSpleen

Gall BladderGall Bladder

PancreasPancreas

LungLung

KidneyKidney

OviductOviduct

Ovaries/Ovaries/EggsEggs

Testes/Testes/SpermSperm

Sperm DuctSperm Duct