🐍 Class Reptilia – The Scaled Land Rulers!

 

🐍 Class Reptilia – The Scaled Land Rulers!

🦎 Reptiles: First Vertebrates to Thrive Entirely on Land

Reptiles were the first truly terrestrial vertebrates, thanks to their amniotic eggs and dry, scaly skin that prevents water loss.

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🧬 Key Features of Class Reptilia:

• Reptiles are the first animals with amniotic eggs.
  These eggs have protective extra-embryonic membranes:

1. Amnion (protects embryo from dehydration)

2. Allantois (stores waste)
3. Chorion (gas exchange membrane)

• Eggs are rich in yolk (main food source) and albumin (protein-rich fluid for nourishment).
• Covered by a leathery or calcareous shell (partly permeable to gases, but not water).
• Dry, scaly skin prevents water loss (unlike moist skin of amphibians).
• Hard bony endoskeleton, tougher than amphibians.
• Skull is longer and stronger.
• Two cervical vertebrae – atlas and axis (allow head to rotate more freely).
• Heart has three chambers, but the ventricle is partially divided (helps in better separation of oxygenated and deoxygenated blood).
• Reptiles are ectothermic (depend on external heat) and poikilothermic (cannot maintain constant body temperature).
• Fertilization is internal. Reproduction mostly occurs via laying eggs (oviparous).

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🐢 Examples of Reptiles:

• Snakes 🐍
• Lizards 🦎
• Crocodiles 🐊
• Turtles 🐢
• Alligators 🐊
• Chameleons 🌿

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