Life Cycle, Processes & Properties, UMB-WHO
None of us are born looking exactly the way that we do today; this is because humans, like other species, undergo a series of changes as they mature and age, in accordance with their biological life cycle. This process can look very different across different species. In many simple organisms and in higher animals, the life cycle is completed within a single generation, while in most plants, the life cycle is multigenerational.
Life Cycle, Processes & Properties Encyclopedia Articles By Title
umbilical cord
umbilical cord, narrow cord of tissue that connects a developing embryo, or fetus, with the placenta (the extra-embryonic......
Unisexuality
Unisexuality, in biology, the condition of an organism or species capable of producing only male or female gametes......
uremia
uremia, medical condition produced by the toxic effects of abnormally high concentrations of nitrogenous substances......
urethritis
urethritis, infection and inflammation of the urethra, the channel for passage of urine from the urinary bladder......
urinary tract infection
urinary tract infection (UTI), in humans, inflammation of the renal system characterized by frequent and painful......
urinary tract obstruction
urinary tract obstruction, blockage or constriction at any point in the urinary tract that impedes the normal flow......
urination
urination, the process of excreting urine from the urinary bladder. Nerve centres for the control of urination......
urine
urine, liquid or semisolid solution of metabolic wastes and certain other, often toxic, substances that the excretory......
urogenital malformation
urogenital malformation, any defect in the organs and tissues responsible for the formation and excretion of urine......
uterine bleeding
uterine bleeding, abnormal bleeding from the uterus, which is not related to menstruation. Menstruation is the......
uterine cancer
uterine cancer, a disease characterized by the abnormal growth of cells in the uterus. Endometrial cancer, which......
uterine fibroid
uterine fibroid, benign tumour that originates from the smooth muscle wall of the uterus and may be single but......
uveitis
uveitis, inflammation of the uvea (or uveal tract), the middle layer of tissue surrounding the eye that consists......
vaccine-associated feline sarcoma
vaccine-associated feline sarcoma, malignant tumour of cats that develops at the site of a vaccine injection. The......
vaginismus
vaginismus, involuntary muscle spasm that closes the opening to the vagina in the female reproductive tract. The......
vaginitis
vaginitis, inflammation of the vagina, usually due to infection. The chief symptom is the abnormal flow of a whitish......
varicose vein
varicose vein, vein that is twisted and distended with blood. The term varix is also used for similar abnormalities......
veganism
veganism, the theory or practice of abstaining from the consumption and use of animal products. While some vegans......
vegetarianism
vegetarianism, the theory or practice of living solely upon vegetables, fruits, grains, legumes, and nutsāwith......
vegetative reproduction
vegetative reproduction, any form of asexual reproduction occurring in plants in which a new plant grows from a......
veliger
veliger, larva typical of certain mollusks such as marine snails and bivalves and a few freshwater bivalves. The......
Venom
Venom, the poisonous secretion of an animal, produced by specialized glands that are often associated with spines,......
ventricular fibrillation
ventricular fibrillation, a type of arrhythmia (abnormal heart rhythm) characterized by the irregular and uncoordinated......
ventricular septal defect
ventricular septal defect, opening in the partition between the two ventricles, or lower chambers, of the heart.......
vertigo
vertigo, sensation of spinning or tilting or that oneās surroundings are rotating. Usually the state produces dizziness,......
vesicular exanthema of swine
vesicular exanthema of swine, viral disease of swine causing eruption of painful blisters on feet and snout. Blisters......
vesicular stomatitis
vesicular stomatitis, viral disease causing blisters in the mouths of cattle, horses, and mules and on the snouts......
vesiculitis
vesiculitis, inflammation and infection of the seminal vesicles in the male reproductive tract. The seminal vesicles......
vestibular system
vestibular system, apparatus of the inner ear involved in balance. The vestibular system consists of two structures......
vestibulocochlear nerve
vestibulocochlear nerve, nerve in the human ear, serving the organs of equilibrium and of hearing. It consists......
Vibrissae
Vibrissae, stiff hairs on the face or nostrils of an animal, such as the whiskers of a cat. Vibrissae often act......
Vincent gingivitis
Vincent gingivitis, acute and painful infection of the tooth margins and gums that is caused by the symbiotic microorganisms......
viral disease
viral disease, disease caused by viruses. Long-term immunity usually follows viral childhood diseases (see chickenpox).......
viral hemorrhagic fever
viral hemorrhagic fever, any of a variety of highly fatal viral diseases that are characterized by massive external......
viroid
viroid, an infectious particle smaller than any of the known viruses, an agent of certain plant diseases. The particle......
vision
vision, physiological process of distinguishing, usually by means of an organ such as the eye, the shapes and colours......
visual field defect
visual field defect, a blind spot (scotoma) or blind area within the normal field of one or both eyes. In most......
Visual pigment
Visual pigment, any of a number of related substances that function in light reception by animals by transforming......
vitamin
vitamin, any of several organic substances that are necessary in small quantities for normal health and growth......
vitamin A deficiency
vitamin A deficiency, nutritional disorder caused by a deficiency of vitamin A (also called retinol), a fat-soluble......
vitiligo
vitiligo, patchy loss of melanin pigment from the skin. Though the pigment-making cells of the skin, or melanocytes,......
Vocalization
Vocalization, any sound produced through the action of an animalās respiratory system and used in communication.......
Volkmann contracture
Volkmann contracture, disorder of the wrist and hand in which the hand and fingers become fixed in a characteristic......
volvulus
volvulus, twisting of a portion of the digestive tract on its mesentery (the fold of membrane that attaches the......
vomiting
vomiting, the forcible ejection of stomach contents from the mouth. Like nausea, vomiting may have a wide range......
von Gierkeās disease
von Gierkeās disease, most common of a group of hereditary glycogen-storage diseases. It is inherited as an autosomal-recessive......
von Willebrand disease
von Willebrand disease, inherited blood disorder characterized by a prolonged bleeding time and a deficiency of......
voyeurism
voyeurism, human sexual behaviour involving achievement of sexual arousal through viewing the sexual activities......
vulvitis
vulvitis, inflammation and infection of the vulvaāthe external genitalia of the female. The external organs of......
Waddington, C.H.
C.H. Waddington was a British embryologist, geneticist, and philosopher of science. Waddington graduated in geology......
Warm-bloodedness
Warm-bloodedness, in animals, the ability to maintain a relatively constant internal temperature (about 37Ā° C [99Ā°......
wart
wart, a well-defined growth of varying shape and size on the skin surface caused by a virus, most commonly one......
Waterhouse-Friderichsen syndrome
Waterhouse-Friderichsen syndrome, a rare type of septicemia (blood poisoning) of rapid and severe onset, marked......
West Nile virus
West Nile virus, virus belonging to the family Flaviviridae, related to viruses that can cause yellow fever and......
whale vocalization
whale vocalization, process used by whales that produces any of several vocal sounds that assist in communication......
whalebone
whalebone, series of stiff keratinous plates in the mouths of baleen whales, used to strain copepods and other......
What animal has the longest life span?
The Greenland shark (Somniosus microcephalus) is the longest-lived vertebrate animal known to science. Radiocarbon......
What Are Gut Bacteria?
Gut bacteria are microorganisms that naturally inhabit the digestive tract. They serve critical roles in the human......
What are the five ways infectious diseases can be spread?
There are five primary ways in which infectious diseases can be spread: direct contact, contact with fomites (inanimate......
What Are the Symptoms of a Stroke?
The onset of stroke can manifest in different ways. In many instances, the affected person may experience sudden......
What causes allergies?
Allergic reactions are caused by substances known as allergens. These substances can be found in a variety of sources......
What Causes Brain Freeze?
Brain freeze, also known as cold-stimulus headache or sphenopalatine ganglioneuralgia, is a phenomenon triggered......
What did Jan Ingenhousz discover about photosynthesis?
Dutch-born British physician and scientist Jan Ingenhousz discovered that light is necessary for photosynthesis.......
What do ants eat?
There are approximately 10,000 species of ants on Earth, with a wide range of diets and behaviors among them. Many......
What do cheetahs eat?
Cheetahs are carnivores, which means that their diet consists primarily of meat. They hunt a variety of animals,......
What do ducks eat?
Ducks are omnivorous birds that feed on both plants and animals. Their varied diet may include aquatic vegetation,......
What do frogs eat?
Frogs have a diverse diet that primarily consists of insects and other small invertebrates, though some species......
What do giraffes eat?
Giraffes, as browsers, primarily feed on new, tender shoots and leaves of trees, with a particular fondness for......
What do kangaroos eat?
Kangaroos are herbivores, which means they eat only plant-based foods. Their diet mainly includes grass and other......
What do rabbits eat?
Rabbits are herbivores and primarily consume a diet rich in plant material, such as grasses and forbs (herbs other......
What do squirrels eat?
Squirrelsā diets vary based on their species and habitat. The most commonly recognized squirrel, the bushy-tailed......
What do turtles eat?
Turtlesā diets vary based on their species and where they live. Many turtles are herbivorous, and mainly live off......
What do whales eat?
Whales have a diverse diet that varies significantly between species, primarily depending on whether they are baleen......
What does a narwhal use its horn for?
A variety of theories have been proposed for the specific function of the narwhalās long, straight tusk, but first......
What Does Photosynthesis Produce?
Photosynthesis produces sugar, with oxygen gas as a by-product. The process of photosynthesis is commonly written......
What eats snakes?
Although snakes are predators, they are also themselves eaten by other creatures, making them secondary consumers......
What Happens to Our Bodies After We Die?
What happens to our bodies after we die isnāt a mystery, even if we may want it to be. If you want to confront......
What Happens When You Swallow Gum?
Your parents may have warned you not to swallow your chewing gum because it would remain in your stomach for seven......
What Happens When You Wake Up from a Coma?
Emerging from a coma is almost never a sudden return to full awareness. Instead, it is usually a gradual process......
What is a group of cows called?
A group of cows is called a herd. This is the standard term used universally in both common speech and scientific......
What Is a Second Wave of a Pandemic, and Could It Happen for COVID-19?
This article was originally published May 15, 2020, and updated October 15, 2020. When a global outbreak of disease......
What Is a Superspreader Event?
The COVID-19 pandemic has caused various scientific terms to become a part of everyday vocabulary, among them the......
What Is the Difference Between a Grain and a Seed?
The word grain is usually used for the edible seeds of a cereal grass, such as rice, barley, or corn (maize). A......
What Is the Difference Between Cardiac Arrest and Heart Attack?
Cardiac arrest is an electrical malfunction in which the heartās rhythm suddenly fails, and it stops beating without......
What Is the Difference Between Dependence and Addiction?
Dependence is primarily a physiological state in which the body adapts to the presence of a substance. Addiction,......
What Is the Difference Between Influenza and COVID-19?
Influenza and the coronavirus disease COVID-19 appear to be very similar. After all, both are respiratory diseases,......
What is the most venomous jellyfish?
The Australian box jellyfish, scientifically named Chironex fleckeri, is widely considered the worldās most venomous......
What Was Life Like Before We Knew About Germs?
āIt was the summer of 1880. It was August. It stank to high heaven. The sewers had been uncorked, and all the filth......
What was the impact of COVID-19?
On February 25, 2020, a top official at the Centers for Disease Control and Prevention decided it was time to level......
What You Need to Know About Cyclosporiasis
In July 2026 a large multistate outbreak in the United States thrust an obscure intestinal illness known as cyclosporiasis......
Whatās the Difference Between a Psychopath and a Sociopath? And How Do Both Differ from Narcissists?
Psychopath and sociopath are often used interchangeably in common speech to describe a person who is pathologically......
Whatās the Difference Between HIV and AIDS?
In the 1980s, a condition called acquired immunodeficiency syndrome, known more widely as AIDS, began to show itself......
Whatās the Difference Between Venomous and Poisonous?
When people talk about dangerous snakes like black mambas and cobras, at least one person in the conversation will......
When Was the Last Pandemic?
This article was originally published on March 19, 2020. The last major global outbreak of disease before the COVID-19......
Which Animal Is the Smartest?
Strictly speaking, humans are the smartest animals on Earthāat least according to human standards. We are adept......
Which parrots are most likely to talk?
Among the 333 species of parrots (family Psittacidae), the African gray parrot (Psittacus erithacus) is the most......
whiplash
whiplash, injury to the cervical spine and its soft tissues caused by forceful flexion or extension of the neck,......
white nose syndrome
white nose syndrome, disease affecting hibernating bats in North America that is caused by the growth of a white......
Who Can Declare a Pandemic and What Criteria Are Required for an Outbreak to Be Called a Pandemic?
This article was originally published on March 18, 2020. The World Health Organization (WHO) is responsible for......
whooping cough
whooping cough, acute, highly communicable respiratory disease characterized in its typical form by paroxysms of......