Biology/Natural History: There is a large amount of molecular and genetic research done on Katharina. The K. tunicata is diploid and has a haploid number of 24. The changes in organic composition of the tissues and systems along with the life cycle of the chiton have also been studied. Lipids and blood proteins levels are high through the majority of the life cycle, but both decrease dramatically prior to spawning. The organic compositions of most other systems remain fairly constant seasonally. Damaged plates can be repaired in just a few weeks. The diet of the black chiton includes brown and red algae as well as benthic diatoms. Reproduction is sexual and full maturity just over a year. The entire life span averages 3 years.