Kevin de Queiroz discusses the concept of species, species criteria, and the process of speciation. He argues that despite the diversity of species definitions, they all align with a general lineage concept of species. This concept views species as segments of population-level evolutionary lineages. The diversity of species definitions arises from the complex and extended nature of species and the processes involved in speciation. De Queiroz proposes a unified terminology for species definitions, distinguishing between species concepts (ideas about the nature of species) and species criteria (standards for determining whether an entity is a species). He outlines various species concepts, including the biological species concept, isolation concept, recognition concept, evolutionary species concept, ecological species concept, cohesion species concept, phylogenetic species concept, and genealogical species concept. Each of these concepts emphasizes different aspects of species, such as interbreeding, reproductive isolation, ecological adaptation, and phylogenetic relationships. De Queiroz also discusses the process of speciation, which involves the splitting of lineages and the development of criteria for identifying species. He argues that the diversity of species definitions is due to the different criteria used to assess species, and that these criteria are related to the processes of speciation. De Queiroz proposes a revised terminology that clarifies the distinction between species concepts and species criteria, and he emphasizes the importance of understanding the general lineage concept of species in evolutionary biology.Kevin de Queiroz discusses the concept of species, species criteria, and the process of speciation. He argues that despite the diversity of species definitions, they all align with a general lineage concept of species. This concept views species as segments of population-level evolutionary lineages. The diversity of species definitions arises from the complex and extended nature of species and the processes involved in speciation. De Queiroz proposes a unified terminology for species definitions, distinguishing between species concepts (ideas about the nature of species) and species criteria (standards for determining whether an entity is a species). He outlines various species concepts, including the biological species concept, isolation concept, recognition concept, evolutionary species concept, ecological species concept, cohesion species concept, phylogenetic species concept, and genealogical species concept. Each of these concepts emphasizes different aspects of species, such as interbreeding, reproductive isolation, ecological adaptation, and phylogenetic relationships. De Queiroz also discusses the process of speciation, which involves the splitting of lineages and the development of criteria for identifying species. He argues that the diversity of species definitions is due to the different criteria used to assess species, and that these criteria are related to the processes of speciation. De Queiroz proposes a revised terminology that clarifies the distinction between species concepts and species criteria, and he emphasizes the importance of understanding the general lineage concept of species in evolutionary biology.