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Habituation to a specific practice, such as drinking alcoholic beverages or using drugs (for example, heroin, cocaine, or amphetamines), and disorders characterized by the chronic use of a drug, alcohol, or similar substance. Addiction and addictive…

Behavior that is intended to threaten or inflict physical injury or emotional harm on another person or organism. Aggression is a type of behavior (physical or verbal, or both) displayed by an individual who aims or is motivated to harm another…

A discipline concerned with solving the engineering problems of providing food and fiber for the people of the world. These problems include designing agricultural machinery to work the soil and harvest the crops, as well as developing water…

The science that deals with the selection, breeding, nutrition, and management of domestic animals for economical production of meat, milk, eggs, wool, hides, and other animal products. The broad field of agricultural science focuses on two realms:…

The techniques and methods used in plowing, harrowing, planting, tilling, harvesting, drying, storing, and processing of agricultural crops. Agricultural soil and crop practices seek to keep the quality and fertility of soils at high levels so as to…

A model for the functioning of an agricultural system, with all inputs and outputs. An ecosystem may be as small as a set of microbial interactions that take place on the surface of roots, or as large as the globe. An agroecosystem may be at the…

The repeated and/or excessive use of alcohol (ethanol) that continues despite negative physical, psychiatric, or social consequences. Alcoholism is characterized by consuming alcohol more often, in larger amounts, or over longer periods than…

A disease of the nervous system characterized by a progressive dementia that leads to profound impairment in cognition and behavior. Dementia occurs in a number of brain diseases where the impairment in cognitive abilities represents a decline from…

The application of genetic principles for improving heredity for economically important traits in domestic animals. The science of animal breeding is based on fundamental genetic concepts. Through controlled mating and selection, which can involve…

The cultivation of freshwater and marine species for human purposes. Aquaculture, or aquatic farming, is concerned with the raising of animals and the harvesting of plants in freshwater and marine environments (Fig. 1). In other words, it is the…

A common psychiatric disorder (especially in children) characterized by attentional difficulties, impulsivity, and hyperactivity. Attention deficit hyperactivity disorder (ADHD) is a mental disorder marked by an individual's inability to pay…

A neurodevelopmental condition that impairs the way that a person relates to and communicates with other people. Persons with autism have difficulties with social communication and interaction. They also can have unusual behaviors, such as…

A fast-growing tree, Ochroma pyramidale (also known as O. lagopus), which is widely distributed in tropical America, especially in Ecuador. Balsa (Ochroma pyramidale; also, O. lagopus) belongs to the mallow family, Malvaceae, in the order Malvales.…

The management and maintenance of colonies of honeybees for human purposes. Beekeeping is an ancient art. Although the commonly known honeybee species (Fig. 1) is native to Europe and Africa, humans have transported them to other continents. The…

Organic materials or wastes produced by plants and animals that can be used as energy sources or fuels. Biomass is a collective term used to describe renewable materials that are derived from plants and animals. In some cases, microbial metabolic…

A major mental disorder in which there are lifelong episodes of both mania and depression; also known as manic-depressive illness. Bipolar disorder, also termed manic-depressive illness or manic depression, is characterized by sudden and often…

A deciduous tree of the genus Betula, which is distributed over much of North America, in Asia (south to the Himalayas), and in Europe. Birch trees are assigned to the genus Betula. They belong to the family Betulaceae (which also contains alders,…

Unwanted, aggressive behavior that involves a real or perceived power inequity. The behavior of bullying is often chronic and includes actions such as threats, spreading rumors, attacking someone physically or verbally, and purposefully excluding or…

The tree Cinnamomum camphora, a member of the laurel family, from which camphor is extracted. The camphor tree (see illustration) belongs to the Lauraceae (laurel) family of plants in the order Laurales. It is a native species of China, Japan, and…

A tropical evergreen shrub or small tree of the genus Coffea (family Rubiaceae), a native of northeast Africa and adjacent southwest Asia, cultivated for the seeds (coffee beans) of its fruit. Members of the genus Coffea (Fig. 1) grow mainly between…

The internal structures and processes that are involved in the acquisition and use of knowledge, including sensation, perception, attention, learning, memory, language, thinking, and reasoning. The mental processes and behaviors that constitute…

Technology used to augment human mental capacity. In contrast, technology is widely used to augment human physical capabilities. We can move faster using cars, we can lift heavier weights using cranes, and we can even fly through the air using…

A learned response performed by a human or other animal to a signal that was previously associated with an event of consequence for that human or animal. A conditioned reflex, also known as a conditioned response, is an acquired response in which…

The state of being aware of one's own existence, of one's mental states, and of the impressions made upon one's senses. Consciousness is central to human existence, yet it has proved difficult to define and characterize. Typically, consciousness…

Zea mays, also known as maize, a grain crop grown for its edible seeds (kernels). Corn (Zea mays) [Fig. 1] is an important cereal grass plant belonging to the order Poales (formerly Cyperales). The top corn-producing countries are the United…

The deliberate conversion of forest to nonforest land that results in the long-term reduction of tree canopy below a minimum level. Deforestation, also known as land clearing, permanently eliminates forests to utilize the land for other purposes…

A syndrome characterized by a generalized decline in cognition that is severe enough to cause functional impairment in daily activities. Dementia is a term used to describe a collection of symptoms of severe cognitive decline. Individuals suffering…

A heterogeneous affective disorder involving a depressed mood and/or a loss of interest in daily activities. The most common form of affective disorder is depression (also termed clinical depression) [Fig. 1]. A major depressive episode is defined…

The study of age-related changes in behavior from birth to death. Developmental psychology is an important branch of psychological analysis that investigates the development and changes of behavior over an individual's lifetime (Fig. 1). In general,…

Disorders characterized by abnormal eating behaviors, extreme weight-control behaviors, and dysfunctional beliefs about eating, weight, and body shape. Individuals suffering from eating disorders display abnormal eating behaviors and extreme…

A term commonly associated with both behaviors and states of mind (known as feelings) that are not under the control of reason and disturb the flow of consciously directed behavior. Emotions influence human thinking and behavior (Fig. 1), and they…