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Chapter 40 Amphibians

Chapter 40 Amphibians. Section 1 Origin and Evolution of Amphibians. Amphibians. Greek word meaning “double” and “life” Many amphibians spend part of their life in water and part on land. Adaptation to Land. Most likely evolved from lobe-finned fishes

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Chapter 40 Amphibians

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  1. Chapter 40Amphibians Section 1 Origin and Evolution of Amphibians

  2. Amphibians • Greek word meaning “double” and “life” • Many amphibians spend part of their life in water and part on land

  3. Adaptation to Land • Most likely evolved from lobe-finned fishes • Pre-adaptations- adaptations in an ancestral group that allow a shift to new functions which are later favored by natural selection

  4. Adaptation to Land • Lobe-finned fish ancestral amphibians- appendages to walk • Had modified pouches in their digestive tract that evolved into lungs • Had nostrils to help aid in breathing on land

  5. Characteristics of Early Amphibians • Amphibians and lobe-finned fishes share many similarities: skull & vertebral column • Sarcopterygian- extinct lobe-finned fish that is thought to be closely related to amphibians

  6. Sarcopterygian

  7. Diversification of Amphibians • 4,500 species belonging to three orders • Anura- frogs and toads • Caudata- salamanders • Gymnophiona- caecilians- legless tropical amphibians

  8. Modern Amphibians • Most change from aquatic larval stage to a terrestrial adult form- metamorphosis • Most have moist, thin skin with no scales • Feet, if present, lack claws and often are webbed

  9. Modern Amphibians • Most use gills, lungs, and skin respiration • Eggs lack multi-cellular membranes or shells. They are usually laid in water or in moist places and are usually fertilized externally

  10. Order Anura • Frogs & toads • World-wide, except in polar climates and a few oceanic islands • Either spend part of or entire live in water • Toad- rough, bumpy skin • Frog- smooth, moist skin

  11. Order Anura • Body adapted for jumping (long muscular legs) • Adult anurans are carnivores • Have a sticky tongue to help capture food • Return to water to reproduce • Tadpoles- fertilized eggs hatch into swimming, tailed larva

  12. Poison Dart Frog

  13. Gray Tree Frog

  14. Bull Frog

  15. Leopard Frog

  16. Cane Toad

  17. American Toad

  18. Order Caudata • Salamanders- elongated bodies, long tails, and moist skin • Smallest are only a few centimeters long, largest are over 4.5 feet • Aquatic and terrestrial species • Carnivores

  19. Order Caudata • Most live in North America and Central America • Some are lungless and breathe through their skin • Some reproduce in water, while others lay eggs on land

  20. Order Caudata • Water reproduction- larval stage • Land reproduction- no larval stage • Internal fertilization • Some terrestrial species stay with eggs until hatched

  21. Spring Salamander

  22. Dusky Salamander

  23. Red-Spotted Newt

  24. Spotted Salamander

  25. Order Gymnophiona • Caecilian- legless amphibian- resembles snakes • Found in tropical areas of Asia, Africa, and South America • 12 inches to 4.5 feet • Often are blind because their eyes are found under skin and bone

  26. Order Gymnophiona • Rarely seen- little is known • Some burrow and some are aquatic • Have teeth- eat worms and other invertebrates

  27. Order Gymnophiona • Internal fertilization • Some species lay eggs & some are born live • Young use their jaws and teeth to scrape secretions “uterine milk” from the walls of the female’s reproduction tract

  28. Sagalla Caecilian

  29. Purple Caecilian

  30. REVIEW!!! • Name some characteristics that are common to modern amphibians. • Compare and contrast the three living orders of amphibians.

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