Phase of life

from Wikipedia, the free encyclopedia

Different periods of time in the development of a living being, which can be differentiated from one another by means of independent characteristics, are referred to as the life phase , development stage or age stage .


The biology is in organisms from a comprehensive life-cycle of ( latin cyclus "circle"), which is divided into four sections:

  1. Pre-life phase
  2. Sexually immature phase
  3. Sexual maturation
  4. adult phase of sexual maturity, with the ability to reproduce

The underlying qualitative characteristics and the delimitation of the phases are not binding, which is why there are not always clear assignments.

Phases of human life

Pythagoras divided human life into four, Hippocrates into seven, and Aristotle into three phases. A division into ten sections was also described in ancient times.

The human life cycle is now divided into embryogenesis and the following life phases of childhood , adolescence and adulthood . There are also special sections within these levels, such as infants and toddlers in childhood and retired senior citizens in adults . The two phases of change in the body, puberty and menopause ( climacteric ) of men and women are biologically determined . The respective psychological aspects are examined by developmental psychology .

Classifications into life phases are also made according to other characteristics, for example within the framework of a career in modern socialization that is regarded as "normal", the life phases of preschool , school , vocational training or study , working life and retirement . Phases of life are thus described by a sequence of life events .

Phases of life also play a role in a legal sense (see, for example, the list of age groups in German law ), in economic policy considerations ( age pyramid ) and in education ( school levels , alternative school systems related to development phases ).

The specific age information for a phase of life, as well as this itself, are to a large extent culturally, socially and economically determined and the study area of social psychology , ethnology (ethnology) and, with regard to Europe, historical folklore .

Life stages of biology

The developmental biology generally speaks of the development stage . In animals , a basic distinction is also made between the life stages of embryonic development , juvenility (childhood and youth) and an adult (adult) stage. Above all pets wear in different phases with different names, so the domestic pig piglets  - runners  - sow or boar , or the Domestic Cattle calf  - Heifer calf or young animal  - cow or bull . As in humans, many higher mammals also have forms of puberty , bachelorhood, and senior age .

Insects and other invertebrates show much more complex phases of development, the metamorphosis and the virgin stages of immature individuals are known.

In plants , the phases of life are determined by the change of generation , in particular there is the phase of the seedling and the diploid vegetative phase. Natural age levels are particularly used in connection with larger stands of plants such as forests .

Lower organisms such as algae , fungi or bacteria have an extensive variety of life stages which, for example in the formation of spores, exceed the limit of the general definition of " life ". Such phases of life can be characterized by complete biological inactivity and last for centuries, in some cases longer.


Web links

Wiktionary: Age level  - explanations of meanings, word origins, synonyms, translations
Wiktionary: phase of life  - explanations of meanings, word origins, synonyms, translations
Wiktionary: period of life  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Dietrich von Engelhardt : Geriatrics. In: Werner E. Gerabek , Bernhard D. Haage, Gundolf Keil , Wolfgang Wegner (eds.): Enzyklopädie Medizingeschichte. De Gruyter, Berlin / New York 2005, ISBN 3-11-015714-4 , pp. 478-481; here: p. 478 f.