Some branches of biology

1. Morphology Study of external form and structure of living organisms.
2. Anatomy Study of internal structure of plants and animals.
3. Histology Study of details of tissue structure of organisms.
4. Cell biology Study of structure, functions, reproduction and life history of cell.
5. Molecular biology Study of physio-chemical organization of biomolecules.
6. Physiology Study of processes and functions associated with life.
7. Genetics Study of heredity and variations.
8. Embryology Study of early stages of development, such as gametes formation, fertilization of eggs and development of embryo.
9. Taxonomy Deals with identification, nomenclature and classification of biological objects.
10. Parasitology Study of parasitic organisms.
11. Palaeo-biology Study of fossil plants and animals.
12. Limnology Study of fresh waters and their inhabitants.
13. Microbiology Study of microorganisms such as bacteria, virus, etc.
14. Psychology Study of human behavior and mental status.
15. Protozoology Study of one celled animals.
16. Evolution  Study of change in living things over time and adaptation to the conditions of environment.
17. Mycology Study of fungi.
18. Phycology  Study of algae.
19. Bryology Study of mosses and liverworts.
20. Helminthology Study of worms.
21. Entomology Study of insects.
22. Ornithology Study of birds.
23. Mammalogy Study of mammals.
24. Herpetology Study of reptiles and amphibians.
25. Biometrics Study of mathematical statistics in relation to biological research.
26. Surgery Study involving physical operations to cure diseases or injuries to the body.
27. Economic biology Study of economically important organisms and their products.
28. Ecology Study of plants and animals in reciprocal relationships with the environment.
29. Palaeontology Study of extinct and fossil organisms.
30. Veterinary Study of diseases of domestic animals and their trestment and health care.
31. Anthropology Study of origin, physical, mental development of mankind in the present and past races with social conditions.
32. Biochemistry Study of chemical substances and chemical processes of living things.
33. Biophysics Application of physics to the study of living things.
34. Exobiology Study of existence of life in outer planets.
35. Aerobiology Study of airborne organisms.
36. Adenology Study of glands.
37. Zoology Study of animals.
38. Botany Study of plants.
39. Cytology Study of cell structure and functions.
40. Virology Study of viruses.
41. Malacology Study of mollusks.
42. Ichthyology Study of fishes.

25 Branches of Biology and Their Definitions & Meaning from A to Z

                                                              Image source: examplespedia

References: 

i) http://www.iasplanner.com/civilservices/ias-pre/general-science/main-branches-of-biology-and-fields-of-biology

ii) https://examplespedia.com/divisions-branches-of-biology/

Some branches of biology