amphibiansamphibians the first vertebrates to live on land

Amphibians

The first vertebrates to live on land.

Necessary adaptations for life on land

1. Legs to support weight of animal & to allow for movement

Necessary adaptations for life on land

2. Lungs and/or cutaneous breathing rather than gills

Necessary adaptations for life on land

3. Heart able to supply more oxygen.

Frog Anatomy

Important TermsDorsal:

Top

Ventral: Bottom

Anterior: Front / head

Posterior: Rear

Frog Anatomy

External Structures

Skin•mucous glands keep skin moist which is necessary for cutaneous respiration• some have glands that produce poisons or foul-tasting substances

oxygen from the air is drawn into a frog's body by the blood vessels that

lie close to the skin.

Eyes•eyes bulge providing protection from predators •has 2 eyelids–one protects from dust –nictitating membrane is

clear & protects under water

Tympanic MembraneThe eardrum of the

frog

Structures of the MouthTongue

attaches at front of mouth so it can flick out to capture prey

Vomarine Teeth2 large teeth in roof of

mouth that impale the prey

(food is swallowed whole)

Structures of the MouthGullet

Opening to the esophagus

GlottisOpening to the

trachea (windpipe)

Structures of the MouthEustachian TubesLead to the Tympanic

Membrane.

Internal NaresNostrals

Frog Anatomy

Internal Structures

Skeleton•Frog has a reduced skeleton (9 vertebrae & no ribs) •Pelvic girdle is adapted to absorb shock from jumping

BrainA larger cerebrum

enables frog to process more

sensory information; large

optic lobe for vision

Digestive System• Esophagus: Tube that

leads to the stomach• Stomach: First site of

chemical digestion, breaks down food

• Liver: Makes bile (aids in digestion)

• Gall bladder: Stores bile• Pancreas: Makes insulin

(aids in digestion)

Digestive System• Small Intestine (duodenum

and ileum): absorb nutrients from food

• Mesentery: Holds coils of the small intestine together

• Spleen: Part of circulatory system, stores blood

• Large Intestine: Collects waste, absorbs water

• Cloaca - "Sewer": eggs, sperm, urine and feces enter this area

Urogenital SystemCombination of the Excretory and Reproductive

systems – they are closely relatedCloaca is the collection cavity for feces, urine, eggs, & sperm - one opening for all these to exit.

Reproductive SystemEggs are not watertight so reproduction must

happen in water.Males produce sperm & females produce eggs, both in large numbers for external fertilization

Reproductive System

Reproductive System

External Frog Anatomy

Forelimb

Ventral

Anterior

Dorsal

Posterior

Hind limb

Foot

HandTympanic Membrane

External Nares

Eye

Nictitating Membrane

Forelimb

Ventral

Anterior

Dorsal

Posterior

Hind limb

Foot

HandTympanic

Membrane

External Nares

Eye

Nictitating Membrane

Structures of the MouthInternal Nares

TongueEustachian Tubes

Maxillary Teeth

Vomarine Teeth

GulletGlottisInternal Nares

Tongue

Eustachian Tubes

Maxillary Teeth

Vomarine Teeth

Gullet

Glottis

Kidneys

Fat Bodies Oviduct

OvaryCloaca

Fat Bodies

Kidneys

Testes

Cloaca

BladderBladder

Kidneys

Fat Bodies

Oviduct

Ovary

Cloaca

Fat Bodies

Kidneys

Testes

Cloaca

Bladder

Bladder

E-mail your dissection pictures to Tommie.Gibbins@birdvilleschools.net

Please…• Get out your notes from

yesterday• Get out something to write

with• Put all belongings at the back

of the classroom!