Biology, AOR-BIO
How do plants feed themselves? How did dogs evolve from wolves? What good is the appendix in humans, anyway? Such questions fall within the domain of biology, which seeks to understand living organisms and their vital processes (although the jury’s still out on what our appendixes are for). Biology’s diverse fields include botany, ecology, evolution, genetics, medicine, physiology, and zoology.
Biology Encyclopedia Articles By Title
aorta, coarctation of the
coarctation of the aorta, congenital malformation involving the constriction, or narrowing, of a short section......
aortic stenosis
aortic stenosis, narrowing of the passage between the left lower chamber (ventricle) of the heart and the aorta,......
aphasia
aphasia, defect in the expression and comprehension of language caused by damage to the temporal and the frontal......
apicomplexan
apicomplexan, any protozoan of the (typically) spore-producing phylum Apicomplexa, which is called by some authorities......
Apomixis
Apomixis, reproduction by special generative tissues without fertilization. It includes parthenogenesis in animals,......
aponeurosis
aponeurosis, a flat sheet or ribbon of tendonlike material that anchors a muscle or connects it with the part that......
apoptosis
apoptosis, in biology, a mechanism that allows cells to self-destruct when stimulated by the appropriate trigger.......
appendix
appendix, in anatomy, a vestigial hollow tube that is closed at one end and is attached at the other end to the......
Apple scab
Apple scab, disease of apple trees caused by the ascomycete fungus Venturia inaequalis. Apple scab is found wherever......
apraxia
apraxia, the inability to carry out useful or skilled acts while motor power and mental capacity remain intact.......
aquarium
aquarium, receptacle for maintaining aquatic organisms, either freshwater or marine, or a facility in which a collection......
aqueous humour
aqueous humour, optically clear, slightly alkaline liquid that occupies the anterior and posterior chambers of......
arboretum
arboretum, place where trees, shrubs, and sometimes herbaceous plants are cultivated for scientific and educational......
arbovirus
arbovirus, acronym derived from arthropod-borne virus, any of a group of RNA viruses that develop in arthropods......
Archaea
Archaea, (domain Archaea), any of a group of single-celled prokaryotic organisms (that is, organisms whose cells......
archinephros
archinephros, ancestral vertebrate kidney, retained by larvae of hagfish and of some caecilians and occurring in......
Are penguins monogamous?
Penguins tend to be monogamous and many species form long-term pair bonds. For instance, macaroni penguins are......
Are There Really Right-Brained and Left-Brained People?
Are you a logical, precise thinker, or would you say that you’re more free-spirited and artistic? If you’re the......
Are viruses living or nonliving?
Viruses are not considered living organisms in the traditional sense. Viruses are unique infectious agents that......
arenavirus
arenavirus, any virus belonging to the family Arenaviridae. The name of the family is derived from the Latin arenosus,......
argentaffin cell
argentaffin cell, one of the round or partly flattened cells occurring in the lining tissue of the digestive tract......
aril
aril, accessory covering of certain seeds that commonly develops from the seed stalk, found in both angiosperms......
arteriosclerosis
arteriosclerosis, chronic disease characterized by abnormal thickening and hardening of the walls of arteries,......
artificial organ
artificial organ, any machine, device, or other material that is used to replace the functions of a faulty or missing......
artificial respiration
artificial respiration, breathing induced by some manipulative technique when natural respiration has ceased or......
Asa Gray: The Father of American Botany
Asa Gray may not be a household name for most people, but the “Father of American Botany” was a remarkable man.......
ascariasis
ascariasis, infection of humans and other mammals caused by intestinal roundworms of the genus Ascaris. In humans,......
ascites
ascites, accumulation of fluid in the peritoneal cavity, between the membrane lining the abdominal wall and the......
ascocarp
ascocarp, fruiting structure of fungi of the phylum Ascomycota (kingdom Fungi). It arises from vegetative filaments......
Ascomycota
Ascomycota, a large phylum of fungi (kingdom Fungi) containing over 64,000 species. Ascomycetes are characterized......
asfarvirus
asfarvirus, any virus belonging to the family Asfarviridae. This family consists of one genus, Asfivirus, which......
aspergillosis
aspergillosis, a number of different disease states in humans that are caused by fungi of the genus Aspergillus,......
Aspergillus
Aspergillus, genus of fungi in the order Eurotiales (phylum Ascomycota, kingdom Fungi) that exists as asexual forms......
asphyxia
asphyxia, the failure or disturbance of the respiratory process brought about by the lack or insufficiency of oxygen......
assortative mating
assortative mating, in human genetics, a form of nonrandom mating in which pair bonds are established on the basis......
Aster yellows
Aster yellows, plant disease, caused by a phytoplasma bacterium, affecting over 300 species of herbaceous broad-leafed......
asthenia
asthenia, a condition in which the body lacks strength or has lost strength, either as a whole or in any of its......
asthenopia
asthenopia, condition in which the eyes are weak and tire easily. It may be brought on by disorders in any of the......
asthma
asthma, a chronic disorder of the lungs in which inflamed airways are prone to constrict, causing episodes of wheezing,......
astigmatism
astigmatism, nonuniform curvature of the cornea (the transparent, dome-shaped tissue located in front of the iris......
astrocyte
astrocyte, star-shaped cell that is a type of neuroglia found in the nervous system in both invertebrates and vertebrates.......
ataxia
ataxia, inability to coordinate voluntary muscular movements. In common usage, the term describes an unsteady gait.......
athetosis
athetosis, slow, purposeless, and involuntary movements of the hands, feet, face, tongue, and neck (as well as......
athlete’s foot
athlete’s foot, fungal infection of the feet, a form of ringworm. The skin areas most commonly affected are the......
atopy
atopy, type of hypersensitivity characterized by an immediate physiological reaction, with movement of fluid from......
atresia and stenosis
atresia and stenosis, absence, usually congenital, of a normal bodily passage or cavity (atresia) or narrowing......
atrial septal defect
atrial septal defect, congenital opening in the partition between the two upper chambers (atria) of the heart.......
atrium
atrium, in vertebrates and the higher invertebrates, heart chamber that receives blood into the heart and drives......
atrophy
atrophy, decrease in size of a body part, cell, organ, or other tissue. The term implies that the atrophied part......
attack rate
attack rate, in epidemiology, the proportion of people who become ill with (or who die from) a disease in a population......
auricle
auricle, in human anatomy, the visible portion of the external ear, and the point of difference between the human......
autecology
autecology, the study of the interactions of an individual organism or a single species with the living and nonliving......
autoantibody
autoantibody, harmful antibody that attacks components of the body called self antigens. Normally autoantibodies......
autoimmune disease
autoimmune disease, any of a group of conditions or disorders that result from malfunction of the immune system,......
autoimmunity
autoimmunity, the state in which the immune system reacts against the body’s own normal components, producing disease......
autonomic nervous system
autonomic nervous system, in vertebrates, the part of the nervous system that controls and regulates the internal......
autophagy
autophagy, the degradation of worn, abnormal, or malfunctioning cellular components that takes place within organelles......
Autosome
Autosome, any of the numbered or nonsex chromosomes of an organism. Humans have 22 sets of autosomes; they are......
avascular necrosis
avascular necrosis, death of bone tissue caused by a lack of blood supply to the affected area. Avascular necrosis......
Aviary
Aviary, a structure for the keeping of captive birds, usually spacious enough for the aviculturist to enter. Aviaries......
Aviculture
Aviculture, raising and care of wild birds in captivity, for the breeding of game stock, the perpetuation of declining......
axial skeleton
axial skeleton, the part of the bony structure of the body that consists of the bones of the skull, the vertebral......
axon
axon, portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically......
babesiosis
babesiosis, any of a group of tick-borne diseases of humans and other animals caused by species of Babesia, protozoans......
Baby Animal Names: From Pups to Puggles to Porcupettes
If you’ve ever wondered what the baby of a particular animal is called, we’re here to help. While pup, cub, chick,......
Bacillus
Bacillus, (genus Bacillus), any of a genus of rod-shaped, gram-positive, aerobic or (under some conditions) anaerobic......
Backcross
Backcross, the mating of a hybrid organism (offspring of genetically unlike parents) with one of its parents or......
bacteremia
bacteremia, the presence of bacteria in the bloodstream, whether associated with active disease or not. The transient......
Bacteria
Bacteria, any of a group of microscopic single-celled organisms that live in enormous numbers in almost every environment......
- Introduction
- Prokaryotes, Microbes, Cells
- Cell Structure, Enzymes, Metabolism
- Capsules, Slime, Layers
- Genetic Content, DNA, Prokaryotes
- Budding, Reproduction, Microorganisms
- Exchange, Genetic, Information
- Reproduction, Nutrition, Environment
- Microorganisms, Symbiosis, Nutrition
- Industrial Uses, Fermentation, Bioremediation
- Antibiotics, Pathogens, Microbes
- Evolution, Microbes, Diversity
- Temperature, Oxygen, pH
- Metabolism, Nutrition, Reproduction
- Autotrophy, Metabolism, Nutrition
- Biosynthesis, Pathways, Metabolism
- DNA, Identification, Classification
- Morphology, Biochemistry, Features
Bacterial disease
Bacterial disease, any of a variety of illnesses caused by bacteria. Until the mid-20th century, bacterial pneumonia......
Bacteriology
Bacteriology, branch of microbiology dealing with the study of bacteria. The beginnings of bacteriology paralleled......
bacteriophage
bacteriophage, any of a group of viruses that infect bacteria. Bacteriophages were discovered independently by......
Bainbridge reflex
Bainbridge reflex, acceleration of the heart rate resulting from increased blood pressure in, or increased distension......
Balfour Biological Laboratory
Balfour Biological Laboratory, institution for women’s biological instruction (1884–1914) at the University of......
ballistospore
ballistospore, in fungi, a spore forcibly propelled from its site. The basidiospores of the mushrooms, produced......
barotrauma
barotrauma, any of several injuries arising from changes in pressure upon the body. Humans are adapted to live......
Basal rot
Basal rot, widespread plant disease caused by a variety of fungi and bacteria that can infect all flower and crop......
base excision repair
base excision repair, pathway by which cells repair damaged DNA during DNA replication. Base excision repair helps......
basidiocarp
basidiocarp, in fungi, a large sporophore, or fruiting body, in which sexually produced spores are formed on the......
Basidiomycota
Basidiomycota, large and diverse phylum of fungi (kingdom Fungi) that includes jelly and shelf fungi; mushrooms,......
Batrachospermum
Batrachospermum, genus of freshwater red algae (family Batrachospermaceae) ranging in colour from violet to blue-green.......
Batten disease
Batten disease, rare and fatal neurodegenerative disease that begins in childhood. The disease is named for British......
bedsore
bedsore, an ulceration of skin and underlying tissue caused by pressure that limits the blood supply to the affected......
behaviour genetics
behaviour genetics, the study of the influence of an organism’s genetic composition on its behaviour and the interaction......
bejel
bejel, chronic infection characterized by eruptions initially in the mouth and on the skin and typically later......
benthos
benthos, the assemblage of organisms inhabiting the seafloor. Benthic epifauna live upon the seafloor or upon bottom......
Bergmann’s Rule
Bergmann’s Rule, in zoology, principle correlating external temperature and the ratio of body surface to weight......
berylliosis
berylliosis, systemic industrial disease caused by poisoning with beryllium, usually involving the lungs but occasionally......
beta-aminoisobutyric acid excretion
beta-aminoisobutyric acid excretion, a metabolic process under simple genetic control in human beings and the higher......
biceps muscle
biceps muscle, any muscle with two heads, or points of origin (from Latin bis, “two,” and caput, “head”). In human......
biennial
biennial, any herbaceous flowering plant that completes its life cycle in two growing seasons. During the first......
bile
bile, greenish yellow secretion that is produced in the liver and passed to the gallbladder for concentration,......
bile acid
bile acid, any of a group of substances derived from cholesterol that play essential roles in the digestion and......
Binary fission
Binary fission, asexual reproduction by a separation of the body into two new bodies, often referred to as daughter......
Bioaccumulation
Bioaccumulation, the increase in the concentration of heavy metals or other toxic chemicals in a living organism’s......
Biochemistry
Biochemistry, study of the chemical substances and processes that occur in plants, animals, and microorganisms......
Bioclimatology
Bioclimatology, branch of climatology that deals with the effects of the physical environment on living organisms......
bioelectric organ
bioelectric organ, system of tissues specialized for the production and use of electrical power in a living organism.......
bioengineering
bioengineering, the application of engineering knowledge to the fields of medicine and biology. The bioengineer......
Biogenetic law
Biogenetic law, postulation, by Ernst Haeckel in 1866, that ontogeny recapitulates phylogeny—i.e., the development......