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In biology, a biological life cycle (or just life cycle when the biological context is clear) is a series of stages of the life of an organism, that begins as a zygote, often in an egg, and concludes as an adult that reproduces, producing an offspring in the form of a new zygote which then itself goes through the same series of stages, the ...
Human embryonic development refers to the development and formation of the human embryo. It is characterised by the process of cell division and cellular differentiation of the embryo that occurs during the early stages of development. In biological terms, human development entails growth from a one-celled zygote to an adult human being.
Life cycles can be divided into two major stages: growth and reproduction. These two cannot take place at the same time, so once reproduction has begun, growth usually ends. [9] This shift is important because it can also affect other aspects of an organism's life, such as the organization of its group or its social interactions. [8]
Documentary films about people by age (3 C) > Developmental stage theories (1 C, 14 P) A. Adolescence (19 C, 42 P) ... Pages in category "Human life stages"
Anatomically modern humans appear in Africa. [103] [104] [105] Around 50 ka they start colonising the other continents, replacing Neanderthals in Europe and other hominins in Asia. 70 ka Genetic bottleneck in humans (Toba catastrophe theory). 40 ka Last giant monitor lizards (Varanus priscus) die out. 35-25 ka Extinction of Neanderthals.
Human embryology is the study of this development during the first eight weeks after fertilization. The normal period of gestation (pregnancy) is about nine months or 40 weeks. The germinal stage refers to the time from fertilization through the development of the early embryo until implantation is completed in the uterus .
The ancients developed an enduring metaphor for a polity's evolution, drawing an analogy between an individual human's life cycle and developments undergone by a body politic: this metaphor was offered, in varying iterations, by Cicero (106–43 BCE), Seneca (c. 1 BCE – 65 CE), Florus (c. 74 CE – c. 130 CE), and Ammianus Marcellinus ...
Humans (Homo sapiens, meaning 'thinking man' or 'wise man') or modern humans (sometimes Homo sapiens sapiens) are the most common and widespread species of primate, and the last surviving species of the genus Homo and the broader australopithecine subtribe. They are great apes characterized by their hairlessness, bipedalism, and high intelligence.