Amphibia

Amphibia is a class of cold-blooded, vertebrate animals characterized by their ability to live both in aquatic and terrestrial environments. They are distinguished by their moist skin, which lacks scales and often functions in respiration, and their biphasic life cycle that includes both aquatic larvae and terrestrial or semi-aquatic adults. Amphibians are found on every continent except Antarctica, with the greatest diversity in tropical regions.

The class Amphibia encompasses three main groups: frogs and toads (order Anura), salamanders and newts (order Caudata or Urodela), and caecilians (order Gymnophiona or Apoda). Frogs and toads are known for their powerful legs and jumping ability, while salamanders and newts have elongated bodies and tails, often retaining their aquatic features into adulthood. Caecilians are legless, burrowing amphibians with primitive features, and are less well-known.

Amphibians typically reproduce via external fertilization, laying eggs in water or moist environments. Their larvae usually develop in aquatic habitats, undergoing metamorphosis to become adult forms capable of terrestrial life. As sensitive indicators of environmental health, amphibians are vulnerable to factors such as pollution, habitat destruction, and climate change. Many species are currently threatened or endangered.

Amphibians play a vital role in ecosystems as both predators and prey, helping control insect populations and supporting a diverse food web. Their permeable skin makes them unique among vertebrates, facilitating respiration and moisture exchange but also increasing their susceptibility to environmental toxins. Conservation efforts aim to protect their habitats and address threats to ensure their continued survival.