Reptilia
(ii)Class - Reptilia
- Class Reptilia includes a diverse group of vertebrates, commonly known as reptiles.
- This group comprises animals like lizards, snakes, turtles, crocodiles, and birds.
- They are ectothermic, meaning their body temperature is regulated by external sources.
General Characteristics:
- Reptiles have dry, scaly skin, which helps prevent water loss.
- They possess a well-developed, bony endoskeleton.
- Limbs, when present, are typically pentadactyl (having five digits).
- Reptiles exhibit a wide range of body forms, from elongated snakes to quadrupedal lizards and turtles.
Respiration:
- Reptiles respire primarily through lungs.
- They lack gills, and respiration is exclusively pulmonary.
- Some reptiles, like turtles, can respire through specialised structures, such as cloaca or buccopharyngeal cavity.
Feeding Habits:
- Reptiles exhibit diverse feeding habits.
- Most reptiles are carnivorous, feeding on insects, small mammals, birds, or other reptiles.
- Some reptiles, like turtles, are herbivorous, feeding on plants and algae.
Circulatory System:
- Reptiles have a three-chambered heart, except for crocodiles and some monitor lizards, which possess a four-chambered heart.
- The heart pumps oxygenated blood to the body and deoxygenated blood to the lungs.
- The partial division of the ventricle helps reduce the mixing of oxygenated and deoxygenated blood.
Excretion:
- Reptiles excrete nitrogenous wastes primarily in the form of uric acid.
- They possess well-developed kidneys that aid in water conservation.
Reproduction:
- Reptiles exhibit diverse modes of reproduction, including oviparity (laying eggs) and viviparity (giving birth to live young).
- Most reptiles lay eggs with leathery shells, which are often buried in soil or sand.
- Some reptiles, like certain species of snakes and lizards, exhibit ovoviviparity, where eggs hatch internally, and young are born alive.
Economic Importance:
- Reptiles have ecological importance as predators and prey in various ecosystems.
- Some reptiles, like crocodiles and alligators, are farmed for their skin, which is used in the leather industry.
- Certain species, like turtles and snakes, are also kept as pets or used for research purposes.
Examples:
- Lizard (multiple species, e.g., Calotes, Hemidactylus)
- Snake (multiple species, e.g., Naja, Python)
- Turtle (multiple species, e.g., Chitra, Eretmochelys)
- Crocodile (multiple species, e.g., Crocodylus porosus)
- Tortoise (multiple species, e.g., Testudo, Geochelone)
- Monitor lizard (multiple species, e.g., Varanus bengalensis)
- Skink (multiple species, e.g., Mabuya carinata)
- Gharial (Gavialis gangeticus).
