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Amphibians

Amphibians. What are amphibians?. Vertebrates Tetrapods (“four feet”) Ectothermic “both ways of life” Special amphibious traits: Respiration through skin Some amphibians are lung-less Metamorphosis. Amphibian Orders. Order Urodela Order Anura Order Apoda. Order Urodela.

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Amphibians

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  1. Amphibians

  2. What are amphibians? • Vertebrates • Tetrapods (“four feet”) • Ectothermic • “both ways of life” • Special amphibious traits: • Respiration through skin • Some amphibians are lung-less • Metamorphosis

  3. Amphibian Orders • Order Urodela • Order Anura • Order Apoda

  4. Order Urodela • Includes salamanders & newts • Have elongated bodies with a tail & four limbs  • Smooth, moist skin for cutaneous respiration • Less able to stay on dry land than anurans

  5. Order Urodela • Size from a few centimeters long to 1.5 meters • Nocturnal when live in drier areas • Lay eggs in water or damp soil • Some bear live young • May or may not go through tadpole stage (some hatch & look like small adult)

  6. Order Anura • Both terrestrial & freshwater species • Tadpole with tail, gills, & two-chambered heart • Adults without a tail, four limbs, & lungs • Frog skin smooth & moist for cutaneous respiration, while toads is rough & warty (poison glands) • Long hind limbs for jumping • Long, forked tongue hinged at front of mouth

  7. Order Apoda • Includes caecilians • Tropical, burrowing,worm like amphibians • Legless • Small eyes & often blind • Eat worms & other invertebrates • Average length 30 centimeters, but can grow up to 1.3 meters • Internal fertilization • Female bear live young

  8. Feeding • Larvae: mostly herbivores • Adults: mostly carnivores

  9. External Amphibian Anatomy • External nares • Tympanic membrane – cover ear • Nictitating Membrane – transparent eyelid • Upper and lower eye lid • Trunk • Head • Forelimb • Hindlimb

  10. External nares Tympanic membrane Nictitating Membrane Upper and lower eye lid Trunk Head Forelimb Hindlimb

  11. Other external features • Webbed feet • Lack of claws • Layout of the “hands” can differ

  12. Skeletal System • Very similar layout to human skeleton • Head, trunk, limbs • Lack of rib cage

  13. Skeletal System • Skull • Scapula • Radioulna • Humerus • Vertebrae • Tibiofibula • Femur • Tarsus • Metatarsus • Carpus • Metacarpus • Phalanges • *Urostyle

  14. Muscular System • Submaxillary • Control of the Forelimbs: • Deltoid • Latissimusdorsi • Pectoralis • Obliques • Recuts abdominus • Linea Alba • Within Hindlegs: • Gastrocnemius • Triceps femoris

  15. Muscular System

  16. Muscular System

  17. Digestive System • Tongue sticky, forked, & hinged at front of mouth so can be extended out to catch insects • Can pull eyes inward to help swallow food • Two, sharp, backward-pointing  vomerine teeth in roof of mouth help prevent prey from escaping • Maxillary teeth line the edge of the upper jaw

  18. Digestive System • Alimentary canal (mouth, esophagus, stomach, small & large intestines, and cloaca) is where food is digested, absorbed & wastes eliminated • Stomach breaks down food • Pyloric sphincter muscle controls movement of food from stomach into first part of small intestine called duodenum

  19. Digestive System • Small intestine • First region: duodenum • Held together by mesentery • Accessory Organs: • Liver makes bile to digest fats • stored in gall bladder • Pancreas

  20. Digestive System • Wastes collect in large intestine • Move into cloaca along with eggs, sperm, & urine until they leave body through the anus

  21. Digestive System

  22. Digestive System

  23. Respiratory System • Differs between larvae and adult • Larvae: use gills and skin • Adult: lungs, some skin • Many salamanders have no lungs • Glottis – connection between the nose and the bronchii • Bronchii – connect glottis to lungs

  24. Respiratory System

  25. Circulatory System • Need more oxygen to burn increased amount of food needed to live on land • Spleen • More complex circulatory system • Double loop blood circulation • pulmonary from heart to lungs • systemic from heart to rest of body

  26. Circulatory System • 3 chamber heart • Left atrium • Right atrium • Ventricle

  27. Circulatory System • Anterior vena cava - from anterior portion of body to heart • Posterior vena cava – from posterior portion of body to heart • Sinus venosus– both vena cava join to enter heart (right atrium) • Blood moves from right atrium to ventricle • From ventricle to lungs through the pulmonary arteries

  28. Circulatory System • Blood moves from lungs back to the heart through the pulmonary veins • Pulmonary veins empty into the left atrium • Left ventricle pumps into ventricle. • Ventricle leads to truncusarteriosus • Truncusarteriosus– large artery leading from heart to the body

  29. Circulatory System

  30. Nervous System • Relatively well developed • Brain is larger

  31. Nervous System • Olfactory lobes • Cerebrum behind olfactory lobes controls muscles • Pineal Gland - produces hormones • Optic lobes • Cerebellumcontrols balance & coordination • Medulla oblongata controls heart rate & breathing • Cranial nerves connect brain & spinal cord, while spinal nerves branch off the spinal cord to muscles & sensory receptors

  32. Brain of the frog

  33. Excretory System • Kidneys – separate liquid waste from blood • Urinary Ducts  bladder  cloaca • On the kidneys: Adrenal Gland • Produces adrenaline

  34. Reproductive System • External fertilization • Females lay eggs in water • Males deposit sperm over eggs

  35. Reproductive System • Male: • Testes • Seminal vesicles • Female: • Ovaries • Oviducts

  36. Growth and Development • Larva • Metamorphosis • Adult

  37. Other adaptations • Dormancy during unfavorable environmental conditions • Hibernate during cold months • Many fat bodies throughout abdomen for energy during hibernation

  38. Sexual Dimorphism • Physical characteristics differ between male and female • “Hands” of frogs are different between male and female • Male: larger “thumb” • Males: vocal sacs • Mating calls • Show dominance

  39. Frog Dissection

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