Photobiology – scientific study of the interactions of light (technically, non-ionizing radiation) and living organisms. The field includes the study of photosynthesis, photomorphogenesis, visual processing, circadian rhythms, bioluminescence, and ultraviolet radiation effects.
Evolutionary developmental biology – field of biology that compares the developmental processes of different organisms to determine the ancestral relationship between them, and to discover how developmental processes evolved.
Paleobiology – discipline which combines the methods and findings of the natural science biology with the methods and findings of the earth science paleontology.
Paleoanthropology – the study of fossil evidence for human evolution, mainly using remains from extinct hominin and other primate species to determine the morphological and behavioral changes in the human lineage, as well as the environment in which human evolution occurred.
Paleontology – study of fossils and sometimes geographic evidence of prehistoric life.
Paleopathology – the study of pathogenic conditions observable in bones or mummified soft tissue, and on nutritional disorders, variation in stature or morphology of bones over time, evidence of physical trauma, or evidence of occupationally derived biomechanic stress.
Molecular neuroscience - studies the biology of the nervous system with molecular biology, molecular genetics, protein chemistry and related methodologies.
Neuroanatomy - study of the anatomy of nervous tissue and neural structures of the nervous system.
Neuroendocrinology - studies the interaction between the nervous system and the endocrine system, that is how the brain regulates the hormonal activity in the body.
Neuroethology - study of animal behavior and its underlying mechanistic control by the nervous system.
Neuroimmunology - study of the nervous system, and immunology, the study of the immune system.
Neuropharmacology - study of how drugs affect cellular function in the nervous system.
Neurophysiology - study of the function (as opposed to structure) of the nervous system.
Neuropsychology - studies the structure and function of the brain related to psychological processes and behaviors. The term is used most frequently with reference to studies of the effects of brain damage in humans and animals.
Systems neuroscience - studies the function of neural circuits and systems. It is an umbrella term, encompassing a number of areas of study concerned with how nerve cells behave when connected together to form neural networks.
Physiology – study of the internal workings of organisms.
Zoology – study of animals, including classification, physiology, development, and behavior. Subbranches include:
Arthropodology – biological discipline concerned with the study of arthropods, a phylum of animals that include the insects, arachnids, crustaceans and others that are characterized by the possession of jointed limbs.
Acarology – study of the taxon of arachnids that contains mites and ticks.
Arachnology – scientific study of spiders and related animals such as scorpions, pseudoscorpions, harvestmen, collectively called arachnids.
Herpetology – study of amphibians (including frogs, toads, salamanders, newts, and gymnophiona) and reptiles (including snakes, lizards, amphisbaenids, turtles, terrapins, tortoises, crocodilians, and the tuataras).
Batrachology – subdiscipline of herpetology concerned with the study of amphibians alone.
Ichthyology – study of fishes. This includes bony fishes (Osteichthyes), cartilaginous fishes (Chondrichthyes), and jawless fishes (Agnatha).
Malacology – branch of invertebrate zoology which deals with the study of the Mollusca (mollusks or molluscs), the second-largest phylum of animals in terms of described species after the arthropods.
Mammalogy – study of mammals, a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems. Mammalogy has also been known as "mastology," "theriology," and "therology." There are about 4,200 different species of animals which are considered mammals.
Cetology – branch of marine mammal science that studies the approximately eighty species of whales, dolphins, and porpoise in the scientific order Cetacea.
Human behavioral ecology – the study of behavioral adaptations (foraging, reproduction, ontogeny) from the evolutionary and ecologic perspectives (see behavioral ecology). It focuses on human adaptive responses (physiological, developmental, genetic) to environmental stresses.
Nematology – scientific discipline concerned with the study of nematodes, or roundworms.