This is how the Library of Congress divides up and organizes the
discipline of Biology, and how books are ordered on the shelves on the
Lower Level of the Science Library.
The system is rather arbitrary and sometimes downright unhelpful, but
it's useful to have some idea of its structure.
QH1-QH705 NATURAL HISTORY (GENERAL). BIOLOGY (GENERAL)
1-199.5 General, incl nature conservation
91-91.8 Marine biology
201-278.5 Microscopy
301-705 Biology (General)
324 Methods of research. Technique
359-425 Evolution
426-470 Genetics
540-559 Ecology
573-671 Cytology
QK1-QK989 BOTANY
1-474.5 General
101-474 Geographical distribution. Phytogeography
474.8-495 Spermatophyta. Phanerogams
494-494.5 Gymnosperms
495 Angiosperms
504-638 Cryptogams
640-707 Plant anatomy
710-899 Plant physiology
900-977.5 Plant ecology
980-989 Evolution of plants
QL1-QL991 ZOOLOGY
1-355 General
362-599.82 Invertebrates
365-369 Protozoa
401-432 Mollusca
434-599.82 Arthropoda
461-599.82 Insects
605-739.3 Chordates. Vertebrates
614-639.6 Fishes
640-669.3 Reptiles and amphibians
671-699 Birds
700-739.3 Mammals
750-795 Animal behavior
791-795 Stories and anecdotes
799 Morphology
801-950.9 Anatomy
951-991 Embryology
QM1-QM695 HUMAN ANATOMY
1-511 General
531-549 Regional anatomy
550-577.8 Human and comparative histology
601-695 Human embryology
QP1-QP981 PHYSIOLOGY
1-345 General, including influences of the environment
351-495 Neurophysiology and neuropsychology
501-801 Animal biochemistry
901-981 Experimenmtal pharmacology
QR1-QR502 MICROBIOLOGY
1-74 General
75-99.5 Bacteria
100-160 Microbial ecology
180-189.5 Immunology
201-353 Pathogenic micro-organisms
355-502 Virology