Category
page 1Life
life
Life is matter that has biological processes, such as signaling and the ability to sustain itself. It is defined descriptively by the capacity for homeostasis, organisation, metabolism, growth, adaptation, response to stimuli, and reproduction. All life eventually reaches a state of death, and none is immortal. Many philosophical definitions of living systems have been proposed, such as self-organizing systems. Defining life is further complicated by viruses, which replicate only in host cells, and the possibility of extraterrestrial life, which could be very different from life on Earth. Life
organism
An organism is any living thing that functions as an individual. Such a definition raises more problems than it solves, not least because the concept of an individual is also difficult. Several criteria, few of which are widely accepted, have been proposed to define what constitutes an organism. Among the most common is that an organism has autonomous reproduction, growth, and metabolism. This would exclude viruses, even though they evolve like organisms.

non-cellular life
life that exists without a cellular structure, such as virusses, viroids, etc.
biological organisation
hierarchy of complex biological structures and systems that define life using a reductionistic approach
assembly theory
theory that characterizes object complexity

carbon-based life
life whose primary component is carbon
living system
open self-organizing living things that interact with their environment