Corals are ancient animals that have been around for millions of years. The oldest known coral fossil dates back to the Cambrian Period, which began about 541 million years ago. Most modern corals belong to the class Anthozoa, which first appeared in the fossil record about 240 million years ago during the Triassic Period.
Corals are colonial organisms, meaning that they are made up of many individual animals called polyps that live together in a group. Each polyp is a small, simple animal with a sac-like body and tentacles. Polyps secrete a hard, calcium carbonate skeleton called a coral reef, which provides a structure for the colony to grow on.
Coral reefs are some of the most diverse and productive ecosystems on Earth. They provide habitat for a wide variety of marine life, including fish, invertebrates, and algae. Coral reefs also play important roles in protecting coasts from storms and erosion and supporting the livelihoods of millions of people around the world through tourism, fishing, and other industries.