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Life Cycle, Processes & Properties

Life cycle, in biology, the series of changes that the members of a species undergo as they pass from the beginning of a given developmental stage to the inception of that same developmental stage in a subsequent generation.

Life Cycle, Processes & Properties Encyclopedia Articles

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Mental disorder
Mental disorder, any illness with significant psychological or behavioral manifestations that is associated with either a painful or distressing symptom or an impairment in one or more important areas of functioning. Mental disorders, in particular their consequences and their treatment, are of...
Encyclopedia / Life Cycle, Processes & Properties
Sigmund Freud
Gestation
Gestation, in mammals, the time between conception and birth, during which the embryo or fetus is developing in the uterus. This definition raises occasional difficulties because in some species (e.g., monkeys and man) the exact time of conception may not be known. In these cases the beginning of...
Encyclopedia / Life Cycle, Processes & Properties
Diagram of a human uterus during the fourth month of pregnancy.
Chemoreception
Chemoreception, process by which organisms respond to chemical stimuli in their environments that depends primarily on the senses of taste and smell. Chemoreception relies on chemicals that act as signals to regulate cell function, without the chemical necessarily being taken into the cell for...
Encyclopedia / Life Cycle, Processes & Properties
Chemoreception enables animals to respond to chemicals that can be tasted and smelled in their environments. Many of these chemicals affect behaviours such as food preference and defense.
Pregnancy
Pregnancy, process and series of changes that take place in a woman’s organs and tissues as a result of a developing fetus. The entire process from fertilization to birth takes an average of 266–270 days, or about nine months. (For pregnancies other than those in humans, see gestation.) A new...
Encyclopedia / Life Cycle, Processes & Properties
pregnancy
Death
Death, the total cessation of life processes that eventually occurs in all living organisms. The state of human death has always been obscured by mystery and superstition, and its precise definition remains controversial, differing according to culture and legal systems. During the latter half of...
Encyclopedia / Life Cycle, Processes & Properties
Prenatal development
Prenatal development, in humans, the process encompassing the period from the formation of an embryo, through the development of a fetus, to birth (or parturition). The human body, like that of most animals, develops from a single cell produced by the union of a male and a female gamete (or sex...
Encyclopedia / Life Cycle, Processes & Properties
human fetus; prenatal development
Birth
Birth, process of bringing forth a child from the uterus, or womb. The prior development of the child in the uterus is described in the article human embryology. The process and series of changes that take place in a woman’s organs and tissues as a result of the developing fetus are discussed in...
Encyclopedia / Life Cycle, Processes & Properties
Sequential changes in the position of the child during labour.
Animal learning
Animal learning, the alternation of behaviour as a result of individual experience. When an organism can perceive and change its behaviour, it is said to learn. That animals can learn seems to go without saying. The cat that runs to its food dish when it hears the sound of the cupboard opening; the...
Encyclopedia / Life Cycle, Processes & Properties
Kanzi's Primal Language (2005) describes researchers' efforts to teach language to a pygmy chimpanzee named Kanzi.
Protein
Protein, highly complex substance that is present in all living organisms. Proteins are of great nutritional value and are directly involved in the chemical processes essential for life. The importance of proteins was recognized by chemists in the early 19th century, including Swedish chemist J?ns...
Encyclopedia / Life Cycle, Processes & Properties
protein synthesis
Metabolism
Metabolism, the sum of the chemical reactions that take place within each cell of a living organism and that provide energy for vital processes and for synthesizing new organic material. Living organisms are unique in that they can extract energy from their environments and use it to carry out...
Encyclopedia / Life Cycle, Processes & Properties
mitochondria and cellular respiration
Poison
Poison, in biochemistry, a substance, natural or synthetic, that causes damage to living tissues and has an injurious or fatal effect on the body, whether it is ingested, inhaled, or absorbed or injected through the skin. Although poisons have been the subject of practical lore since ancient times,...
Encyclopedia / Life Cycle, Processes & Properties
blue-ringed octopus
Human ear
Human ear, organ of hearing and equilibrium that detects and analyzes sound by transduction (or the conversion of sound waves into electrochemical impulses) and maintains the sense of balance (equilibrium). The human ear, like that of other mammals, contains sense organs that serve two quite...
Encyclopedia / Life Cycle, Processes & Properties
Structure of the human ear.
Human digestive system
Human digestive system, the system used in the human body for the process of digestion. The human digestive system consists primarily of the digestive tract, or the series of structures and organs through which food and liquids pass during their processing into forms absorbable into the...
Encyclopedia / Life Cycle, Processes & Properties
The human digestive system as seen from the front.
Paedomorphosis
Paedomorphosis, retention by an organism of juvenile or even larval traits into later life. There are two aspects of paedomorphosis: acceleration of sexual maturation relative to the rest of development (progenesis) and retardation of bodily development with respect to the onset of reproductive a...
Encyclopedia / Life Cycle, Processes & Properties
Human eye
Human eye, in humans, specialized sense organ capable of receiving visual images, which are then carried to the brain. The eye is protected from mechanical injury by being enclosed in a socket, or orbit, which is made up of portions of several of the bones of the skull to form a four-sided pyramid,...
Encyclopedia / Life Cycle, Processes & Properties
A horizontal cross section of the human eye, showing the major parts of the eye, including the protective covering of the cornea over the front of the eye.
Human respiratory system
Human respiratory system, the system in humans that takes up oxygen and expels carbon dioxide. The human gas-exchanging organ, the lung, is located in the thorax, where its delicate tissues are protected by the bony and muscular thoracic cage. The lung provides the tissues of the human body with a...
Encyclopedia / Life Cycle, Processes & Properties
human lungs
Animal development
Animal development, the processes that lead eventually to the formation of a new animal starting from cells derived from one or more parent individuals. Development thus occurs following the process by which a new generation of organisms is produced by the parent generation. In multicellular...
Encyclopedia / Life Cycle, Processes & Properties
embryos of different animals
Aging
Aging, progressive physiological changes in an organism that lead to senescence, or a decline of biological functions and of the organism’s ability to adapt to metabolic stress. Aging takes place in a cell, an organ, or the total organism with the passage of time. It is a process that goes on over...
Encyclopedia / Life Cycle, Processes & Properties
primates

Life Cycle, Processes & Properties Encyclopedia Articles

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