Amphibian

Biofluorescence in Ceratophrys cranwelli - 41598 2020 59528 Fig2-bottom (cropped)

Paratype of Paedophryne amauensis (LSUMZ 95004)

Triadobatrachus

Diplocaulus vale21DB

Eryops - National Museum of Natural History - IMG 1974

Amphibians are a group of vertebrate animals that include all members of the class Amphibia. This class is characterized by its life cycle that typically involves a water-bound larval stage followed by a terrestrial adult stage. The three main orders within this class are Anura (frogs and toads), Urodela (or Caudata, salamanders and newts), and Gymnophiona (caecilians, which are limbless and resemble worms or snakes). Amphibians are ectothermic (or cold-blooded) animals, relying on external sources of temperature to regulate their body heat.

Characteristics

Amphibians are distinguished by their dual-life, with the early stage of their life cycle spent in water, where they breathe through gills, and the adult stage living primarily on land, breathing air through lungs and their skin. Their skin is highly permeable to water and contains glands that produce mucus, which helps to keep it moist. This unique skin makes amphibians highly sensitive to environmental changes, serving as bioindicators of ecosystem health.

The reproduction of amphibians is also notable, with most species undergoing external fertilization in aquatic environments. Eggs are laid in water and undergo a process of metamorphosis, transforming from larval forms with gills to adult forms with lungs. Some species exhibit direct development, bypassing the larval stage entirely.

Habitat and Distribution

Amphibians are found in a wide range of habitats, including tropical rainforests, deserts, mountains, and arctic regions. However, they are most abundant and diverse in moist, tropical areas. Their distribution is global, except for Antarctica, but many species are endemic to specific regions and habitats, making them vulnerable to habitat destruction and climate change.

Conservation

Amphibians are among the most threatened groups of animals on Earth, with a significant number of species facing risks of extinction. The primary threats to amphibians include habitat loss, pollution, disease (notably the chytrid fungus which has devastated populations worldwide), climate change, and invasive species. Conservation efforts are critical to protect these species, involving habitat preservation, captive breeding programs, and disease management strategies.

Cultural Significance

Throughout history, amphibians have held various roles in human culture, from symbols of fertility and rebirth in ancient civilizations to subjects of scientific study and conservation efforts today. Their unique life cycle and diverse forms have made them a subject of fascination and study, contributing valuable insights into evolutionary biology and ecology.