Biology, CYS-EFF

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.
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Biology Encyclopedia Articles By Title

cyst
cyst, in biology, enclosed sac within body tissues, having a distinct membrane and generally containing a liquid......
cystinosis
cystinosis, inborn error of metabolism resulting in the deposition of crystals of the amino acid cystine in various......
cystinuria
cystinuria, hereditary error of metabolism characterized by the excessive excretion into the urine of four amino......
cystitis
cystitis, acute or chronic inflammation of the urinary bladder. The bladder, the storage sac for urine, is lined......
cytogenetics
cytogenetics, in cell biology, field that deals with chromosomes and their inheritance, particularly as applied......
cytokinesis
cytokinesis, in biology, the process by which one cell physically divides into two cells. Cytokinesis represents......
cytology
cytology, the study of cells as fundamental units of living things. The earliest phase of cytology began with the......
cytomegalovirus
cytomegalovirus (CMV), any of several viruses in the herpes family (Herpesviridae), frequently involved in human......
cytoplasm
cytoplasm, the semifluid substance of a cell that is external to the nuclear membrane and internal to the cellular......
cytoplasmic streaming
cytoplasmic streaming, the movement of the fluid substance (cytoplasm) within a plant or animal cell. The motion......
cytoskeleton
cytoskeleton, a system of filaments or fibres that is present in the cytoplasm of eukaryotic cells (cells containing......
dacryocystitis
dacryocystitis, inflammation and infection of the lacrimal sac, usually stemming from obstruction of the flow of......
damping-off
damping-off, destructive disease of plant seedlings. Damping-off is caused by a number of seed- and soil-borne......
Darwinism
Darwinism, theory of the evolutionary mechanism propounded by Charles Darwin as an explanation of organic change.......
de Toni–Fanconi syndrome
de Toni–Fanconi syndrome, a metabolic disorder affecting kidney transport, characterized by the failure of the......
deafness
deafness, partial or total inability to hear. The two principal types of deafness are conduction deafness and nerve......
death cap
death cap, (Amanita phalloides), species of poisonous mushroom, the deadliest known to humans. The death cap is......
defecation
defecation, the act of eliminating solid or semisolid waste materials (feces) from the digestive tract. In human......
dehydration
dehydration, loss of water from the body; it is almost invariably associated with some loss of salt (sodium chloride)......
delayed puberty
delayed puberty, failure of the physical development of the reproductive system by the normal stage or period of......
delirium
delirium, a mental disturbance marked by disorientation and confused thinking in which the patient incorrectly......
deltoideus muscle
deltoideus muscle, large, triangular muscle that covers the shoulder and serves mainly to raise the arm laterally.......
delusion
delusion, in psychology, a rigid system of beliefs with which a person is preoccupied and to which the person firmly......
deme
deme, in biology, a population of organisms within which the exchange of genes is completely random; i.e., all......
dementia
dementia, general term for any of a number of conditions marked by chronic, usually progressive deterioration of......
dendrology
dendrology, study of the characteristics of trees, shrubs, lianas, and other woody plants. Dendrology is generally......
denitrifying bacteria
denitrifying bacteria, microorganisms whose action results in the conversion of nitrates in soil to free atmospheric......
deoxyribose
deoxyribose, five-carbon sugar component of DNA (q.v.; deoxyribonucleic acid), where it alternates with phosphate......
dermatitis
dermatitis, an inflammation of the skin usually characterized by redness, swelling, blister formation, and oozing......
dermatochalasis
dermatochalasis, sagging of the eyelid skin and underlying muscle that occurs commonly during the aging process.......
dermatomyositis
dermatomyositis, chronic progressive inflammation of the skin and muscles, particularly the muscles of the shoulders......
dermis
dermis, the thicker, deeper layer of the skin underlying the epidermis and made up of connective tissue. It is......
desmid
desmid, (order Desmidiales), order of single-celled (sometimes filamentous or colonial) microscopic green algae,......
detached retina
detached retina, eye disorder involving separation of the transparent light-sensing portion of the retina from......
deuteromycetes
deuteromycetes, fungi (kingdom Fungi) in which a true sexual state is uncommon or unknown. Many of these fungi......
Devonian extinctions
Devonian extinctions, a series of mass extinction events primarily affecting the marine communities of the Devonian......
diabetes
diabetes, either of two disorders of the endocrine system. For information about the disorder caused by the body’s......
diabetes insipidus
diabetes insipidus, pathological endocrine condition characterized by excessive thirst and excessive production......
diabetes mellitus
diabetes mellitus, disorder of carbohydrate metabolism characterized by impaired ability of the body to produce......
diabetic nephropathy
diabetic nephropathy, deterioration of kidney function occurring as a complication of diabetes mellitus. The condition......
diapause
diapause, spontaneous interruption of the development of certain animals, marked by reduction of metabolic activity.......
diaphragm
diaphragm, dome-shaped, muscular and membranous structure that separates the thoracic (chest) and abdominal cavities......
diarrhea
diarrhea, abnormally swift passage of waste material through the large intestine, with consequent discharge of......
diastole
diastole, in the cardiac cycle, period of relaxation of the heart muscle, accompanied by the filling of the chambers......
diatom
diatom, (class Bacillariophyceae), any member of the algal class Bacillariophyceae (division Chromophyta), with......
dieback
dieback, common symptom or name of disease, especially of woody plants, characterized by progressive death of twigs,......
Diego blood group system
Diego blood group system, classification of human blood according to the properties conferred by the presence of......
digestion
digestion, sequence by which food is broken down and chemically converted so that it can be absorbed by the cells......
digestive system, invertebrate
invertebrate digestive system, any of the systems used by invertebrates for the process of digestion. Included......
digit malformation
digit malformation, in human physiology, any of the isolated anomalies of the digits (fingers or toes) in an otherwise......
dilator muscle
dilator muscle, any of the muscles that widen a body part. In humans, the dilator muscle of the iris contains fibres......
dinoflagellate
dinoflagellate, (division Dinoflagellata), any of numerous one-celled aquatic organisms bearing two dissimilar......
diphtheria
diphtheria, acute infectious disease caused by the bacillus Corynebacterium diphtheriae and characterized by a......
diplomonad
diplomonad, any member of the protozoan order Diplomonadida. Diplomonads are small zooflagellates that inhabit......
disease
disease, any harmful deviation from the normal structural or functional state of an organism, generally associated......
dissociative disorder
dissociative disorder, any of several mental disturbances in humans in which normally integrated mental functions,......
diverticulum
diverticulum, any small pouch or sac that forms in the wall of a major organ of the human body. Diverticula form......
DNA
DNA, organic chemical of complex molecular structure that is found in all prokaryotic and eukaryotic cells and......
DNA fingerprinting
DNA fingerprinting, in genetics, method of isolating and identifying variable elements within the base-pair sequence......
DNA repair
DNA repair, any of several mechanisms by which a cell maintains the integrity of its genetic code. DNA repair ensures......
dog years explained
How do dogs age in comparison with humans? And are seven dog years really equivalent to one year of human life?......
Dollo’s law
Dollo’s law, biological principle, formulated about 1890 by Louis Dollo, a French-born Belgian paleontologist,......
Dolly
Dolly, female Finn Dorset sheep that lived from 1996 to 2003, the first clone of an adult mammal, produced by British......
Dombrock blood group system
Dombrock blood group system, classification of human blood based on the presence of certain glycoproteins, originally......
dominance
dominance, in genetics, greater influence by one of a pair of genes (alleles) that affect the same inherited character.......
dormancy
dormancy, state of reduced metabolic activity adopted by many organisms under conditions of environmental stress......
double vision
double vision, perceiving of two images of a single object. Normal binocular vision results from the brain’s fusion......
dourine
dourine, venereal disease of horses, caused by the protozoan Trypanosoma equiperdum. The disease, which involves......
downy mildew
downy mildew, disease of plants, especially in cool humid regions, caused by several funguslike organisms of the......
drowning
drowning, suffocation by immersion in a liquid, usually water. Water closing over the victim’s mouth and nose cuts......
drug allergy
drug allergy, hypersensitivity reaction to therapeutic agents that occasionally occurs on subsequent exposure to......
drug resistance
drug resistance, Property of a disease-causing organism that allows it to withstand drug therapy. In any population......
dry rot
dry rot, symptom of fungal disease in plants, characterized by firm spongy to leathery or hard decay of stem (branch),......
ductus deferens
ductus deferens, thick-walled tube in the male reproductive system that transports sperm cells from the epididymis,......
Duffy blood group system
Duffy blood group system, classification of human blood based on the presence of glycoproteins known as Fy antigens......
dulse
dulse, (Palmaria palmata), edible red alga (Rhodophyta) found along the rocky northern coasts of the Atlantic and......
duodenum
duodenum, the first part of the small intestine, which receives partially digested food from the stomach and begins......
Dupuytren’s contracture
Dupuytren’s contracture, flexion deformity of the hands caused by thickening of the fascia, or fibrous connective......
Dutch elm disease
Dutch elm disease, widespread fungoid killer of elms (Ulmus species) and certain other trees, first described in......
dwarfism
dwarfism, condition of growth retardation resulting in abnormally short adult stature and caused by a variety of......
dysarthria
dysarthria, motor speech disorder in which neurological damage impairs the ability of nerves to send messages to......
dysentery
dysentery, infectious disease characterized by inflammation of the intestine, abdominal pain, and diarrhea with......
dysplasia
dysplasia, malformation of a bodily structure or tissue; the term most commonly denotes a malformation of bone.......
dystonia
dystonia, movement disorder characterized by the involuntary and repetitive contraction of muscle groups, resulting......
ear bone
ear bone, any of the three tiny bones in the middle ear of all mammals. These are the malleus, or hammer, the incus,......
eating disorders
eating disorders, atypical eating patterns, including anorexia nervosa, bulimia, compulsive overeating, and pica......
Ebola
Ebola, contagious disease caused by a virus of the family Filoviridae that is responsible for a severe and often......
ebolavirus
ebolavirus, genus of viruses in the family Filoviridae, certain members of which are particularly fatal in humans......
echinococcosis
echinococcosis, formation of cysts, or hydatids, at the site of infestation by the larval form of Echinococcus......
ecology
ecology, study of the relationships between organisms and their environment. Some of the most pressing problems......
ectopic pregnancy
ectopic pregnancy, condition in which the fertilized ovum (egg) has become imbedded outside the uterine cavity.......
ectropion
ectropion, outward turning of the border (or margin) of the eyelid (usually the lower eyelids). The condition most......
edema
edema, in medicine, an abnormal accumulation of watery fluid in the intercellular spaces of connective tissue.......
Edwards v. Aguillard
Edwards v. Aguillard, case in which the U.S. Supreme Court on June 19, 1987, ruled (7–2) that a Louisiana statute......
effective population size
effective population size, in genetics, the size of a breeding population, a factor that is determined by the number......

Biology Encyclopedia Articles By Title