Biology, GEN-HIG
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
gender dysphoria
gender dysphoria (GD), formal diagnosis given by mental health professionals to people who experience distress......
gene
gene, unit of hereditary information that occupies a fixed position (locus) on a chromosome. Genes achieve their......
gene flow
gene flow, the introduction of genetic material (by interbreeding) from one population of a species to another,......
gene pool
gene pool, sum of a population’s genetic material at a given time. The term typically is used in reference to a......
gene-for-gene coevolution
gene-for-gene coevolution, a specific form of reciprocal evolutionary change based on the idea that, if one member......
genetic disease, human
human genetic disease, any of the diseases and disorders that are caused by mutations in one or more genes of the......
- Introduction
- Sex Chromosome Abnormalities
- Autosomal Dominant, Inheritance, Genes
- Sex-Linked Inheritance
- Cancer Genetics, Mutations, Oncogenes
- Environmental Agents, Mutations, Diagnosis
- UV Radiation, Causes, Symptoms
- Prevention, Diagnosis, Treatment
- Estimating Probability, Bayes' Theorem
- Prenatal Diagnosis
- Genetic Testing, Inheritance, Diagnosis
- Ethical Issues
genetic drift
genetic drift, a change in the gene pool of a small population that takes place strictly by chance. Genetic drift......
genetic epidemiology
genetic epidemiology, the study of how genes and environmental factors influence human traits and human health......
genetics
genetics, study of heredity in general and of genes in particular. Genetics forms one of the central pillars of......
genetics, human
human genetics, study of the inheritance of characteristics by children from parents. Inheritance in humans does......
genome-wide association study
genome-wide association study (GWAS), systematic approach to rapidly scanning the human genome for genetic variations,......
genomics
genomics, one of several omic branches of biological study, concentrates on the structure, function, and inheritance......
genotype
genotype, the genetic constitution of an organism. The genotype determines the hereditary potentials and limitations......
genus
genus, biological classification ranking between family and species, consisting of structurally or phylogenetically......
geographic mosaic theory of coevolution
geographic mosaic theory of coevolution, in ecology, the theory postulating that the long-term dynamics of coevolution......
germ theory
germ theory, in medicine, is the scientific principle that infectious diseases are caused by specific microorganisms......
germ-plasm theory
germ-plasm theory, concept of the physical basis of heredity expressed by the 19th-century biologist August Weismann......
germination
germination, the sprouting of a seed, spore, or other reproductive body, usually after a period of dormancy. The......
Gestation
Gestation, in mammals, the time between conception and birth, during which the embryo or fetus is developing in......
gestational age
gestational age, length of time that a fetus grows inside the mother’s uterus. Gestational age is related to the......
gestational diabetes mellitus
gestational diabetes mellitus, temporary condition in which blood sugar (glucose) levels increase during pregnancy......
gestational trophoblastic disease
gestational trophoblastic disease, any of a group of rare conditions in which tumours develop in the uterus from......
giant cell
giant cell, large cell characterized by an arc of nuclei toward the outer membrane. The cell is formed by the fusion......
gigantism
gigantism, excessive growth in stature, well beyond the average for the individual’s heredity and environmental......
Gill
Gill, in biology, type of respiratory organ found in many aquatic animals, including a number of worms, nearly......
Gizzard
Gizzard, in many birds, the hind part of the stomach, especially modified for grinding food. Located between the......
gland
gland, cell or tissue that removes specific substances from the blood, alters or concentrates them, and then either......
glanders
glanders, infectious disease of primarily horses, but also mules and donkeys, that is caused by the bacterium Burkholderia......
glaucoma
glaucoma, disease caused by an increase in pressure within the eye as a result of blockage of the flow of aqueous......
Gliding bacterium
Gliding bacterium, any member of a heterogeneous group of microorganisms that exhibit creeping or gliding forms......
glottis
glottis, either the space between the vocal fold and arytenoid cartilage of one side of the larynx and those of......
Gluconeogenesis
Gluconeogenesis, formation in living cells of glucose and other carbohydrates from other classes of compounds.......
gluteus muscle
gluteus muscle, any of the large, fleshy muscles of the buttocks, stretching from the back portion of the pelvic......
glycogen storage disease
glycogen storage disease, any of a group of enzymatic deficiencies resulting in altered glycogen metabolism. They......
Glycogenesis
Glycogenesis, the formation of glycogen, the primary carbohydrate stored in the liver and muscle cells of animals,......
Glycogenolysis
Glycogenolysis, process by which glycogen, the primary carbohydrate stored in the liver and muscle cells of animals,......
goitre
goitre, enlargement of the thyroid gland, resulting in a prominent swelling in the front of the neck. The normal......
Goitrogen
Goitrogen, substance that inhibits the synthesis of the thyroid hormones (thyroxine and triiodothyronine), thereby......
Golden algae
Golden algae, (class Chrysophyceae), class of about 33 genera and some 1,200 species of algae (division Chromophyta)......
Golgi apparatus
Golgi apparatus, membrane-bound organelle of eukaryotic cells (cells with clearly defined nuclei) that is made......
gonad
gonad, in zoology, primary reproductive gland that produces reproductive cells (gametes). In males the gonads are......
Gonyaulax
Gonyaulax, genus of dinoflagellate algae (family Gonyaulacaceae) that inhabit marine, fresh, or brackish water.......
Good genes hypothesis
Good genes hypothesis, in biology, an explanation which suggests that the traits females choose when selecting......
Gorilla gorilla, Sula sula, and Other Animals Whose Names Are Tautonyms—the Same for Genus and Species
Among scientists, all species are uniquely identified using a system of two parts composed of each organism’s genus......
gout
gout, metabolic disorder characterized by recurrent acute attacks of severe inflammation in one or more of the......
Gram-negative bacterium
Gram-negative bacterium, any of various types of bacteria that are characterized by having a thin peptidoglycan......
Gram-positive bacterium
Gram-positive bacterium, any of various types of bacteria that are characterized by having a thick peptidoglycan......
granulocyte
granulocyte, any of a group of white blood cells (leukocytes) that are characterized by the large number and chemical......
Gray mold rot
Gray mold rot, disease of plants growing in humid areas that is caused by fungi in the genus Botrytis, usually......
Green algae
Green algae, members of the division Chlorophyta, comprising between 9,000 and 12,000 species. The photosynthetic......
gregarine
gregarine, any protozoan of the sporozoan class Gregarinidea (or Gregarinea). Gregarines occur as parasites in......
ground substance
ground substance, an amorphous gel-like substance present in the composition of the various connective tissues.......
group selection
group selection, in biology, a type of natural selection that acts collectively on all members of a given group.......
Growth curve
Growth curve, in biology, a curve in graph form that shows the change in the number of cells (or single-celled......
Growth medium
Growth medium, solution freed of all microorganisms by sterilization (usually in an autoclave, where it undergoes......
Guinea worm disease
Guinea worm disease, infection in humans caused by a parasite known as the guinea worm (Dracunculus medinensis).......
Gulf War syndrome
Gulf War syndrome, cluster of illnesses in veterans of the Persian Gulf War (1990–91). Gulf War syndrome is characterized......
Gymnodinium
Gymnodinium, genus of marine or freshwater dinoflagellate algae (family Gymnodiniaceae). Like all dinoflagellates,......
gymnostome
gymnostome, any ciliated protozoan of the large holotrichous order Gymnostomatida; included are oval to elongated......
Haemophilus
Haemophilus, genus of bacteria that, though often coccobacillus, vary widely in shape in the family Pasteurellaceae.......
hair
hair, in mammals, the characteristic threadlike outgrowths of the outer layer of the skin (epidermis) that form......
hairball
hairball, gastrointestinal obstruction occurring in cats and resulting from accumulation of swallowed hair; the......
hallucination
hallucination, the experience of perceiving objects or events that do not have an external source, such as hearing......
hamartoma
hamartoma, benign tumourlike growth made up of normal mature cells in abnormal number or distribution. While malignant......
hammertoe
hammertoe, deformity of the second, third, or fourth toe in which the toe is bent downward at the middle joint......
hamstring
hamstring, any of the three muscles at the back of the thigh that begin at the pelvis (specifically originating......
hantavirus
hantavirus, (genus Hantavirus), any member of a genus of viruses (Orthohantavirus) of the family Hantaviridae that......
haplosporidian
haplosporidian, any protozoan of the sporozoan subclass Haplosporea. They are internal parasites of invertebrates......
Hardy-Weinberg law
Hardy-Weinberg law, an algebraic equation that describes the genetic equilibrium within a population. It was discovered......
Harpellales
Harpellales, order of fungi (phylum Glomeromycota, kingdom Fungi) with a vegetative body (thallus) consisting of......
Hartnup disease
Hartnup disease, inborn metabolic disorder involving the amino acid tryptophan. Normally, one of the metabolic......
haustorium
haustorium, highly modified stem or root of a parasitic plant or a specialized branch or tube originating from......
Havana syndrome
Havana syndrome, claimed medical condition reported among U.S. diplomats and other government employees stationed......
headache
headache, pain in various parts of the head. Headaches affect nearly everyone at some time in their life, recurrent......
heart
heart, organ that serves as a pump to circulate the blood. It may be a straight tube, as in spiders and annelid......
heart disease
heart disease, broad term encompassing a range of disorders that affect the heart’s structure and function. Heart......
heart rate
heart rate, the number of times the ventricles of the heart contract and relax (that is, beat) per minute or other......
Heart rot
Heart rot, any of several diseases of trees, root crops, and celery. Most trees are susceptible to heart-rotting......
heart sound
heart sound, audible rhythmic vibrations in the heart, typically heard through a stethoscope pressed to the chest......
heartworm disease
heartworm disease, parasitic disease, predominantly of dogs but also occurring in cats, that is caused by the nematode......
heaves
heaves, chronic disorder of the lungs of horses and cows, characterized by difficult breathing and wheezy cough.......
HeLa cell
HeLa cell, type of cancer cell belonging to the first continuously cultured human cell line, established in 1951......
Helicosporidium
Helicosporidium, protozoan parasite genus found in insects. It is the only genus of the cnidosporidian phylum Myxozoa......
hematinic
hematinic, any vitamin or other substance that serves as a building block in the formation of blood components,......
hematology
hematology, branch of medical science concerned with the nature, function, and diseases of the blood. In the 17th......
hemoglobinopathy
hemoglobinopathy, any of a group of disorders caused by the presence of variant hemoglobin in the red blood cells.......
hemolysis
hemolysis, breakdown or destruction of red blood cells so that the contained oxygen-carrying pigment hemoglobin......
hemophilia
hemophilia, hereditary bleeding disorder caused by a deficiency of a substance necessary for blood clotting (coagulation).......
hepadnavirus
hepadnavirus, any virus belonging to the family Hepadnaviridae. Hepadnaviruses have small, enveloped, spherical......
herbarium
herbarium, collection of dried plant specimens mounted on sheets of paper. The plants are usually collected in......
herd immunity
herd immunity, state in which a large proportion of a population is able to repel an infectious disease, thereby......
hereditary spherocytosis
hereditary spherocytosis, congenital blood disorder characterized by an enlarged spleen, spherical (rather than......
heredity
heredity, the sum of all biological processes by which particular characteristics are transmitted from parents......
- Introduction
- Mendelian Genetics, Genes, Traits
- Genetics, Mendel's Laws, Universality
- Epistatic Genes, Genetics, Inheritance
- Genes, DNA, Chromosomes
- Chromosomes, Genes, Meiosis
- Sex Linkage, Chromosomes, Genes
- Chromosome, Genes, Mutations
- DNA, Genes, Inheritance
- DNA Structure, Composition, Genetics
- Transcription, Translation, Genetics
- Genes, DNA, Inheritance
- Mutations, Genes, DNA
- Extranuclear DNA, Genes, Chromosomes
- Gene Frequency, Variation, Evolution
- Genetic Drift, Variation, Evolution
- Evolution, Genetics, DNA
heritability
heritability, amount of phenotypic (observable) variation in a population that is attributable to individual genetic......
hernia
hernia, protrusion of an organ or tissue from its normal cavity. The protrusion may extend outside the body or......
herpangina
herpangina, mild viral infection with sudden onset that is caused by several types of enteroviruses and seen most......
herpesvirus
herpesvirus, any virus belonging to the family Herpesviridae. These viruses are pathogenic (disease-causing) in......
herpetology
herpetology, scientific study of amphibians and reptiles. Like most other fields of vertebrate biology (e.g., ichthyology,......
Hibernation
Hibernation, a state of greatly reduced metabolic activity and lowered body temperature adopted by certain mammals......
high-risk pregnancy
high-risk pregnancy, pregnancy in which the mother, the fetus, or the newborn has an elevated risk of experiencing......