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All organisms follow a specific sequence in their development, [9] beginning with gestation and ending with death, which is known as the life cycle. Events in between usually include birth, childhood, maturation, reproduction, and senescence, and together these comprise the life history strategy of that organism.
The deep sea or alkaline hydrothermal vent theory posits that life began at submarine hydrothermal vents. [ 228 ] [ 229 ] William Martin and Michael Russell have suggested that life evolved in structured iron monosulphide precipitates in a seepage site hydrothermal mound at a redox, pH, and temperature gradient between sulphide-rich ...
Life-cycle assessment (LCA or life cycle analysis) is a technique used to assess potential environmental impacts of a product at different stages of its life. This technique takes a "cradle-to-grave" or a "cradle-to-cradle" approach and looks at environmental impacts that occur throughout the lifetime of a product from raw material extraction, manufacturing and processing, distribution, use ...
Some scientists have proposed in the last few decades that a general theory of living systems is required to explain the nature of life. [1] Such a general theory would arise out of the ecological and biological sciences and attempt to map general principles for how all living systems work. Instead of examining phenomena by attempting to break ...
The goal of the theory of nucleosynthesis is to explain the vastly differing abundances of the chemical elements and their several isotopes from the perspective of natural processes. The primary stimulus to the development of this theory was the shape of a plot of the abundances versus the atomic number of the elements.
Water, as well as sufficiently long-lived stable stars, both essential for the emergence of life as it is known, would not exist. [13] More generally, small changes in the relative strengths of the four fundamental interactions can greatly affect the universe's age, structure, and capacity for life.
The Gaia hypothesis (/ ˈ ɡ aɪ. ə /), also known as the Gaia theory, Gaia paradigm, or the Gaia principle, proposes that living organisms interact with their inorganic surroundings on Earth to form a synergistic and self-regulating complex system that helps to maintain and perpetuate the conditions for life on the planet.
Metabolism (/ m ə ˈ t æ b ə l ɪ z ə m /, from Greek: μεταβολή metabolē, "change") is the set of life-sustaining chemical reactions in organisms.The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks of proteins, lipids, nucleic acids, and some carbohydrates; and the ...