How are the reptilians different from amphibians?
1 Answer
Mar 15, 2017
Evolutionarily, reptiles are one step ahead of amphibians . There are several differences, would enlist few.
Explanation:
- Amphibians lay eggs in water, reptiles lay shelled eggs on land
- Eggs in amphibia are mesolecithal (with moderate amount of yolk) while those of reptilia are megalecithal (with huge amount of yolk)
- Early embryonic development includes complete cleavage in amphibians; cleavage is incomplete in reptilia
- During embryonic development, reptilians develop water filled amniotic sac. Amhibians are anamniotic.
- Amphibian skin is naked and moist (due to presence of mucous glands) while reptilian skin is scaly and dry
- Respiratory gas exchange can take place through moist skin in amphibia, it is not so in case of reptiles
- Most amphibians start life as larvae: hence undergo metamorphosis; reptiles do not have any larval stage in lifecycle
- In larval stage, gills are functional in amphibia. Reptiles do not have gills after birth
- Amphibians lack claw at ends of digits, reptiles possess well developed keratinised claws
- Amphibians may secrete poison from skin gland; reptiles' bite could be highly poisonous
- Skull is dicondylic in amphibia, monocondylic in reptilia
- Amphibians are generally ureotelic (excrete urea); reptilians are mainly uricotelic (excrete uric acid)
- Amphibians have three chambered heart (two auricles and one ventricle), while ventricle remains incompletely divided in case of reptilians
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