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Edward Hitchcock's fold-out paleontological chart in his 1840 Elementary Geology. Although tree-like diagrams have long been used to organise knowledge, and although branching diagrams known as claves ("keys") were omnipresent in eighteenth-century natural history, it appears that the earliest tree diagram of natural order was the 1801 "Arbre botanique" (Botanical Tree) of the French ...
Life is a quality that distinguishes matter that has biological processes, such as signaling and self-sustaining processes, from matter that does not. It is defined descriptively by the capacity for homeostasis , organisation , metabolism , growth , adaptation , response to stimuli , and reproduction .
Non-cellular life, also known as acellular life, is life that exists without a cellular structure for at least part of its life cycle. [1] Historically, most definitions of life postulated that an organism must be composed of one or more cells, [2] but, for some, this is no longer considered necessary, and modern criteria allow for forms of life based on other structural arrangements.
Pasteur and others used the term biogenesis as the opposite of spontaneous generation, to mean that life was generated only from other life. Pasteur's claim followed the German physician Rudolf Virchow 's doctrine Omnis cellula e cellula ("all cells from cells"), [ 49 ] itself derived from the work of Robert Remak .
The emergence of life with increasing order and complexity does not contradict the second law of thermodynamics, which states that overall entropy never decreases, since a living organism creates order in some places (e.g. its living body) at the expense of an increase of entropy elsewhere (e.g. heat and waste production).
However, the prevailing view is that, the Somb was the first tree on Earth and the progenitor of plant life. [48] [49] The Somb was also used in the Serer tumuli and burial chambers, many of which have survived for more than a thousand years. [48] Thus, Somb is not only the tree of life in Serer society but the symbol of immortality. [48]
Plant physiology encompasses all the internal chemical and physical activities of plants associated with life. [155] Chemicals obtained from the air, soil and water form the basis of all plant metabolism. The energy of sunlight, captured by oxygenic photosynthesis and released by cellular respiration, is the basis of almost all life.
The first English use of the expression "meaning of life" appears in Thomas Carlyle's Sartor Resartus (1833–1834), book II chapter IX, "The Everlasting Yea". [1]Our Life is compassed round with Necessity; yet is the meaning of Life itself no other than Freedom, than Voluntary Force: thus have we a warfare; in the beginning, especially, a hard-fought battle.