Chemoautotrophs are organisms that obtain energy by oxidizing inorganic substances, such as hydrogen sulfide or ammonia. Unlike plants, they do not rely on sunlight for energy. Instead, they use chemical reactions to convert carbon dioxide into organic compounds, which they use for growth and energy. These organisms are often found in extreme environments, such as deep-sea hydrothermal vents or hot springs. They play a crucial role in ecosystems by forming the base of the food chain in these habitats, supporting other life forms. Examples of chemoautotrophs include certain bacteria and archaea, which thrive in harsh conditions.