Biology, ILI-LIC

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

iliocostalis muscle
iliocostalis muscle, any of the deep muscles of the back that, as part of the erector spinae (sacrospinalis) muscle......
iliotibial band syndrome
iliotibial band syndrome (ITBS), inflammation of the band of fibrous tissue known as the iliotibial band (or tract),......
iminoglycinuria
iminoglycinuria, inborn impairment of the transport system of the kidney tubules, which normally reabsorb the amino......
immunization
immunization, process by which resistance to disease is acquired or induced in plants and animals. This discussion......
immunodeficiency
immunodeficiency, defect in immunity that impairs the body’s ability to resist infection. The immune system may......
immunology
immunology, the scientific study of the body’s resistance to invasion by other organisms (i.e., immunity). In a......
impetigo
impetigo, inflammatory skin infection that begins as a superficial blister or pustule that then ruptures and gives......
implantation
implantation, in reproduction physiology, the adherence of a fertilized egg to a surface in the reproductive tract,......
in vitro fertilization
in vitro fertilization (IVF), medical procedure in which mature egg cells are removed from a woman, fertilized......
inborn error of metabolism
inborn error of metabolism, any of multiple rare disorders that are caused by an inherited genetic defect and that......
inbreeding
inbreeding, the mating of individuals or organisms that are closely related through common ancestry, as opposed......
incidence
incidence, in epidemiology, occurrence of new cases of disease, injury, or other medical conditions over a specified......
inclusive fitness
inclusive fitness, theory in evolutionary biology in which an organism’s genetic success is believed to be derived......
induced pluripotent stem cell
induced pluripotent stem cell (iPS cell), immature cell that is generated from an adult (mature) cell and that......
induction
induction, in embryology, process by which the presence of one tissue influences the development of others. Certain......
industrial melanism
industrial melanism, the darkness—of the skin, feathers, or fur—acquired by a population of animals living in an......
infancy
infancy, among humans, the period of life between birth and the acquisition of language approximately one to two......
infant and toddler development
infant and toddler development, the physical, emotional, behavioral, and mental growth of children from ages 0......
infantile hemangioma
infantile hemangioma, a congenital benign tumour made up of endothelial cells (the cells lining the inner surface......
infarction
infarction, death of tissue resulting from a failure of blood supply, commonly due to obstruction of a blood vessel......
infectious bovine keratoconjunctivitis
infectious bovine keratoconjunctivitis, an inflammation of the conjunctiva or the cornea of the eye in cattle as......
infertility
infertility, the inability of a couple to conceive and reproduce. Infertility is defined as the failure to conceive......
inflammation
inflammation, a response triggered by damage to living tissues. The inflammatory response is a defense mechanism......
influenza
influenza, an acute viral infection of the upper or lower respiratory tract that is marked by fever, chills, and......
influenza A H1N1
influenza A H1N1, virus that is best known for causing widespread outbreaks, including epidemics and pandemics,......
inky cap
inky cap, (genus Coprinus), genus of about 350 cosmopolitan mushroom species. Inky caps are so named for the disintegration......
inner ear
inner ear, part of the ear that contains organs of the senses of hearing and equilibrium. The bony labyrinth, a......
inoculation
inoculation, process of producing immunity that consists of introduction of the infectious agent into the body.......
instinct
instinct, an inborn impulse or motivation to action typically performed in response to specific external stimuli.......
intercostalis muscle
intercostalis muscle, in human physiology, any of a series of short muscles that extend between the ribs and serve......
International HapMap Project
International HapMap Project, an international collaboration aimed at the identification of genetic variations......
intestinal gas
intestinal gas, material contained within the digestive tract that consists principally of swallowed air and partly......
intestinal juice
intestinal juice, clear to pale yellow, watery secretion composed of hormones, digestive enzymes, mucus, and neutralizing......
intestine
intestine, tubular part of the alimentary canal that extends from the stomach to the anus. The intestine is the......
intracellular fluid
intracellular fluid, substance within living cells that is made up primarily of water and molecules such as dissolved......
ion channel
ion channel, protein expressed by virtually all living cells that creates a pathway for charged ions from dissolved......
iridovirus
iridovirus, any virus belonging to the family Iridoviridae. Iridoviruses possess large enveloped or nonenveloped......
Irish moss
Irish moss, (Chondrus crispus), species of red algae (family Gigartinaceae) that grows abundantly along the rocky......
itching
itching, a stimulation of free nerve endings, usually at the junction of the dermis and epidermis of the skin,......
jaw
jaw, either of a pair of bones that form the framework of the mouth of vertebrate animals, usually containing teeth......
Johne’s disease
Johne’s disease, serious infectious disease caused by Mycobacterium avium paratuberculosis. Although principally......
joint disease
joint disease, any of the diseases or injuries that affect human joints. Arthritis is no doubt the best-known joint......
K-selected species
K-selected species, species whose populations fluctuate at or near the carrying capacity (K) of the environment......
kappa organism
kappa organism, gram-negative symbiotic bacterium found in the cytoplasm of certain strains of the protozoan Paramecium......
karyotype
karyotype, visual representation of the complete set of chromosomes in a cell. In a karyotype, the chromosomes,......
Kawasaki syndrome
Kawasaki syndrome, rare, acute inflammatory disease of unknown origin that is one of the leading causes of acquired......
Kell blood group system
Kell blood group system, classification of human blood based on the presence on the surfaces of red blood cells......
kelp
kelp, (order Laminariales), any of about 30 genera of brown algae that grow as large coastal seaweeds in colder......
keratitis
keratitis, inflammation of the cornea, the transparent domelike portion of the eyeball in front of the iris and......
keratosis
keratosis, any protuberance on the skin resulting from the overdevelopment of the horny outermost covering of the......
kernicterus
kernicterus, severe brain damage caused by an abnormal concentration of the bile pigment bilirubin in brain tissues......
ketosis
ketosis, metabolic disorder marked by high levels of ketones in the tissues and body fluids, including blood and......
Kidd blood group system
Kidd blood group system, classification of human blood based on the presence of glycoproteins known as Kidd (Jk)......
kidney
kidney, in vertebrates and some invertebrates, organ that maintains water balance and expels metabolic wastes.......
king oyster mushroom
king oyster mushroom, (Pleurotus eryngii), widely cultivated edible mushroom. King oyster mushrooms are native......
kinocilium
kinocilium, filamentous structure occurring on auditory hair cells in the inner ear that functions in the development......
klebsiella
klebsiella, (genus Klebsiella), any of a group of rod-shaped bacteria of the family Enterobacteriaceae. Klebsiella......
knee
knee, hinge joint that is formed by the meeting of the thigh bone (femur) and the larger bone (tibia) of the lower......
knee-jerk reflex
knee-jerk reflex, sudden kicking movement of the lower leg in response to a sharp tap on the patellar tendon, which......
Kupffer cell
Kupffer cell, any of the stellate (star-shaped) cells in the linings of the liver sinusoids. The sinusoids are......
kuru
kuru, infectious fatal degenerative disorder of the central nervous system found primarily among the Fore people......
kwashiorkor
kwashiorkor, condition caused by severe protein deficiency. Kwashiorkor is most often encountered in developing......
K–T extinction
K–T extinction, a global mass extinction event responsible for eliminating approximately 80 percent of all species......
Laboulbeniales
Laboulbeniales, an order of fungi in the class Laboulbeniomycetes (phylum Ascomycota, kingdom Fungi) that includes......
labour
labour, in human physiology, the physical activity experienced by the mother during parturition (q.v.), or...
lactation
lactation, secretion and yielding of milk by females after giving birth. The milk is produced by the mammary glands,......
lactic-acid bacterium
lactic-acid bacterium, any member of several genera of gram-positive, rod- or sphere-shaped bacteria that produce......
Lactobacillus
Lactobacillus, (genus Lactobacillus), any of a group of rod-shaped, gram-positive, non-spore-forming bacteria of......
lactose intolerance
lactose intolerance, inability to digest lactose, the predominant sugar in dairy products. It affects people by......
Lamarckism
Lamarckism, a theory of evolution based on the principle that physical changes in organisms during their lifetime—such......
Lamaze
Lamaze, method of childbirth that involves psychological and physical preparation by the mother for the purpose......
Langerhans, islets of
islets of Langerhans, irregularly shaped patches of endocrine tissue located within the pancreas of most vertebrates.......
large intestine
large intestine, posterior section of the intestine, consisting typically of four regions: the cecum, colon, rectum,......
larva
larva, stage in the development of many animals, occurring after birth or hatching and before the adult form is......
laryngeal hemiplegia
laryngeal hemiplegia, in horses, partial or complete paralysis of muscles controlling the vocal fold and other......
larynx
larynx, a hollow, tubular structure connected to the top of the windpipe (trachea); air passes through the larynx......
late blight
late blight, disease of potato and tomato plants that is caused by the water mold Phytophthora infestans. The disease......
latissimus dorsi
latissimus dorsi, widest and most powerful muscle of the back. It is a large, flat, triangular muscle covering......
laver
laver, (genus Porphyra), genus of 60–70 species of marine red algae (family Bangiaceae). Laver grows near the high-water......
leaf blister
leaf blister, worldwide disease of many woody plants and ferns caused by fungi of the genus Taphrina. Peach leaf......
leishmaniasis
leishmaniasis, human protozoal infection spread by the bite of a sandfly. Leishmaniasis occurs worldwide but is......
lek
lek, in animal behaviour, communal area in which two or more males of a species perform courtship displays. Lek......
lens
lens, in anatomy, a nearly transparent biconvex structure suspended behind the iris of the eye, the sole function......
lens dislocation
lens dislocation, abnormal position of the crystalline lens of the eye. The dislocation, which may be congenital,......
leptin receptor
leptin receptor, molecule that receives and transmits signals from leptin, a hormone released from fat cells that......
leptospirosis
leptospirosis, acute systemic illness of animals, occasionally communicable to humans, that is characterized by......
lesion
lesion, in physiology, a structural or biochemical change in an organ or tissue produced by disease processes or......
leukemia
leukemia, a cancer of the blood-forming tissues characterized by a large increase in the numbers of white blood......
leukocytosis
leukocytosis, abnormally high number of white blood cells (leukocytes) in the blood circulation, defined as more......
leukopenia
leukopenia, abnormally low number of white blood cells (leukocytes) in the blood circulation, defined as less than......
leukoplakia
leukoplakia, precancerous tumour of the mucous membranes, usually seen in the mouth or on the tongue or cheeks,......
leukorrhea
leukorrhea, flow of a whitish, yellowish, or greenish discharge from the vagina of the female that may be normal......
levator muscle
levator muscle, any of the muscles that raise a body part. In humans these include the levator anguli oris, which......
Lewis blood group system
Lewis blood group system, classification of human blood based on the expression of glycoproteins called Lewis (Le)......
lichen
lichen, any of about 15,000 species of plantlike organisms that consist of a symbiotic association of algae (usually......

Biology Encyclopedia Articles By Title