In general, biosignatures can be grouped into ten broad categories:
#Isotope patterns: Isotopic evidence or patterns that require biological processes.
#Chemistry: Chemical features that require biological activity.
#Organic matter: Organics formed by biological processes.
#Minerals: Minerals or biomineral-phases whose composition and/or morphology indicate biological activity (e.g., biomagnetite).
#Microscopic structures and textures: Biologically formed cements, microtextures, microfossils, and films.
#Macroscopic physical structures and textures: Structures that indicate microbial ecosystems, biofilms (e.g., stromatolites), or fossils of larger organisms.
#Temporal variability: Variations in time of atmospheric gases, reflectivity, or macroscopic appearance that indicates life's presence.
#Surface reflectance features: Large-scale reflectance features due to biological pigments could be detected remotely.
#Atmospheric gases: Gases formed by metabolic and/or aqueous processes, which may be present on a planet-wide scale.
#Technosignatures: Signatures that indicate a technologically advanced civilization.