A species is a group of living organisms that share similar characteristics and can reproduce with one another to produce fertile offspring. For example, all domestic dogs belong to the same species, known as Canis lupus familiaris, because they can mate and have puppies together. Each species has its own unique traits, such as size, color, and behavior, which help it adapt to its environment. Scientists classify species to better understand the diversity of life on Earth. This classification helps in studying ecosystems and conservation efforts. For instance, the Endangered Species Act aims to protect species at risk of extinction, ensuring that they can thrive for future generations.