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Presentation on theme: "Amphibians."— Presentation transcript:

1 Amphibians

2 Characteristics of Amphibians
Vertebrate Lives in water as larva; land as adult (some exceptions) Breathes with lungs as adult Moist skin with mucus glands No scales and claws

3 Evolution of Amphibians
First amphibians during Devonian Period Transitioned from water to land Breathe air Protect eggs and themselves from drying out Support against the pull of gravity

4 Evolution Continued… Adaptations evolved to live at least part of life out of water. Stronger bones in limbs and limb girdles; more efficient movement Lungs and breathing tubes Sternum or breastbone for shield and support.

5 Lungs Pelvic Girdle 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.

6 As Adults lungs are richly supplied with blood vessels and folds that increase surface area

7 Class Amphibia Includes frogs, toads, salamanders, and caecilians.
Small and diverse class Due to extinction of most amphibians during Permian Period (climate changes) Low, swampy habitats disappeared

8 Feeding Tadpoles Adults Filter feeders or herbivores (algae)
Intestine breaks down hard plant material Adults Carnivores Sticky tongues to capture insects

9 Respiration Gas exchange through skin and gills (larval stage)
Lungs, skin, and lining of mouth cavity (adult stage) Lungless amphibians: thin lining of mouth cavity and skin

10 Circulation Double loop First loop
Oxygen-poor blood from heart to lungs and skin Oxygen-rich blood from lungs and skin to left atrium Second loop Oxygen-rich blood from heart to rest of body Oxygen-poor blood from body back to heart

11 Amphibian Heart Three separate chambers Left atrium Right atrium
To body, lungs and skin From Body From Lungs Three separate chambers Left atrium Right atrium Ventricle Right atrium Left atrium Ventricle

12 Excretion Kidneys to filter wastes from blood
Urine excreted; travels from ureters to cloaca to outside or stored in urinary bladder Heart Lung Kidney Ureter Urinary bladder Cloaca

13 Reproduction Females lay eggs in water; male fertilizes them externally (most amphibians) Internal fertilization (salamanders) After fertilization; frog eggs encased in sticky, transparent jelly Yolk of egg nourishes embryo

14 Movement Wiggle tails; flattened tails for propulsion (larva)
Adult salamanders walk or run Frogs and toads: well developed hind limbs (jump long distances)

15 Response Well developed nervous and sensory systems
Nictitating Membrane Moist and transparent Located inside regular eyelid Can be closed over the eye Tympanic Membrane Eardrums located on each side Lateral Line Used to detect movement in water


17 Frog Digestion Food enters the mouth  esophagus  stomach  small intestine  large intestine  cloaca Cloaca: muscular cavity where solid waste, urine, eggs and sperm exit body Liver, pancreas and gall bladder excrete enzymes that aid in digestion Frog Movie

18 Mouth Esophagus Liver Gallbladder Stomach Small intestine Pancreas Large intestine (colon) Cloaca

19 Frog Reproduction Adults ready to breed in 1 to 2 years
Eggs laid in water (external fertilization) Fertilized eggs  tadpoles (several days to few weeks) Tadpoles gradually lose tails and gills, grow limbs.


21 Frog Metamorphosis Adult Frog Fertilized eggs Young Frog Tadpoles

22 3 Groups of Amphibians Salamanders Frogs and Toads Caecilians

23 Salamanders Long tails and bodies 4 legs Carnivorous
Live in moist woods (adults) Tunnel under rocks and rotting logs


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


27 Caecilians Legless animals that live in water or burrow in moist soil
Feed on small invertebrates (termites) Fish-like scales embedded in their skin


29 Frog Dissection

30 External Anatomy

31 Tympanum

32 External Nares

33 Internal Nares

34 Vomerine Teeth

35 Tongue

36 Eustachian Tube

37 Maxillary Teeth

38 Dorsal Muscular Anatomy

39 2. Pterygoideus 3. Temporalis 4. Masseter 5. Depressor mandibularis 6. Trapezius 11.Latissimus dorsi 14.External oblique 17.Gluteus 18.Piriformis 20.Vastus externus 25.Gracilis minor 26.Gastrocnemius 28.Semimembranosus 29.Biceps femoris

40 4.Masseter 5.Depressor mandibularis 6.Dorsalis scapulae 10.Trapezius

41 55.Depressor mandibularis

42 Ventral Muscular Anatomy

43 7.Deltoid 9.Pectoralis major 12.Rectus abdominus 13.Linea alba 14.External oblique 30.Mylohyoid

44 7 37.Deltoid 9.Pectoralis major 13.Linea alba 20.Rectus femoris 21.Adductor magnus 22.Sartorius 24.Gracilis major 25.Gracilis minor 26.Gastrocnemius 27.Achilles tendon 30.Mylohyoid

45 Internal Anatomy

46 Cerebellum

47 Cerebrum

48 Liver

49 Heart 2 Atria 1 Ventricle

50 Stomach

51 Large Intestine

52 Spleen

53 Gall Bladder

54 Pancreas

55 Lung

56 Kidney

57 Oviduct

58 Ovaries/ Eggs

59 Testes/ Sperm

60 Sperm Duct

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