Description: Amphibians are a class of cold-blooded vertebrates that include frogs, toads, and salamanders. They are characterized by their ability to live both in water and on land, which gives them a crucial role in ecosystems. Their skin is permeable, allowing them to absorb water and oxygen, but also making them vulnerable to pollution. Amphibians undergo a life cycle that includes an aquatic larval stage, where they breathe through gills, and a terrestrial adult stage, where they develop lungs. This duality in their habitat and physiology makes them bioindicators, meaning their health reflects environmental quality. Additionally, amphibians play an important role in the food chain, acting as both predators and prey. Their diversity is remarkable, with over 7,000 known species that vary in size, color, and behavior. Most amphibians are nocturnal and have special adaptations, such as the ability to change color for camouflage. Their study is essential for understanding biodiversity and the effects of climate change, as many species are endangered due to habitat loss and emerging diseases.
History: Amphibians have a long evolutionary history dating back over 350 million years, when the first vertebrates began to colonize land. It is believed that the ancestors of modern amphibians emerged from lobe-finned fish, allowing them to adapt to a terrestrial environment. During the Carboniferous period, amphibians were abundant and diverse, but their numbers have drastically declined in recent centuries due to factors such as urbanization and pollution. In the 20th century, more systematic studies of their biology and ecology began, leading to a greater understanding of their importance in ecosystems.
Uses: Amphibians are used in scientific research, particularly in studies of toxicology and ecology. Their permeable skin makes them ideal subjects for investigating the effects of environmental pollutants. Additionally, they are important in medicine, as some compounds derived from their skin have antimicrobial and analgesic properties. In education, amphibians are often used in school laboratories to teach about biology and life cycles.
Examples: An example of amphibians used in research is the use of the species Xenopus laevis frogs in studies of embryonic development. Additionally, the skin of some frogs has been studied for its medicinal properties, such as in the case of the poison dart frog, which produces toxins used by some indigenous cultures to poison arrows. In the educational field, frogs and salamanders are commonly used in biology classes to illustrate concepts of anatomy and physiology.
