Chromalveolata is a diverse group of eukaryotic organisms that includes various algae, protozoa, and some plants. This group is characterized by the presence of chloroplasts derived from red algae through a process called secondary endosymbiosis. Members of Chromalveolata play essential roles in aquatic ecosystems, contributing to primary production and serving as food sources for various marine organisms. The group is divided into two main clades: Alveolata and Stramenopiles. Alveolata includes organisms like dinoflagellates and ciliates, while Stramenopiles encompasses diatoms and brown algae. Together, these organisms exhibit a wide range of forms and functions, highlighting the complexity of life in aquatic environments.