🌿 Class Amphibia – The Dual Life Survivors!

✨ Amphibians: First Tetrapods to Conquer Land & Water!

• They live both in water and on land, making them the pioneers of evolution among vertebrates.

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🧠 Key Features of Class Amphibia:

• First tetrapod class (four-limbed vertebrates)
• Bony endoskeleton
• Neck present – allows vertical skull movement
• Smooth, moist skin – no scales
• Skin functions in gas exchange, water absorption, and temperature regulation
• Double-circuit heart (3 chambers: 2 atria, 1 ventricle)
• Larvae respire via gills, adults via lungs and skin
• Cold-blooded (ectothermic) and poikilothermic
• Hibernate in winter
• Unisexual with external fertilization

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🐸 Types of Amphibians:

• Tailed: Salamander, newts, mud puppies
• Tailless: Frogs, toads
• Legless: Caecilians

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