Organismin

Organismin is not a widely used biological term; in most scientific contexts the corresponding word is organism. If encountered, it may be a misspelling or a coined form referring to a living being. This article uses the standard concept of an organism to convey the common ideas associated with living systems.

An organism is any individual living system that carries out essential life processes and maintains homeostasis. Organisms range from single-celled forms such as bacteria and many protists to complex multicellular organisms such as plants, animals, and fungi.

Key features include cellular organization, metabolism, growth, response to stimuli, reproduction, and adaptation through evolution. Organisms extract energy and matter from their environment, transform it, and maintain internal conditions within viable limits.

Biologists classify organisms into groups based on evolutionary relationships. The highest-level division is into three domains: Bacteria, Archaea, and Eukarya. Within Eukarya, major groups include Animalia, Plantae, Fungi, and various protist lineages.

Most multicellular organisms have specialized cells organized into tissues and organs, whereas many single-celled organisms perform all life functions within one cell.

Organisms reproduce to pass on genetic information, and they interact with other living things and with abiotic factors, forming communities and ecosystems in which energy flows and matter cycles.

The concept of an organism has a long history in science, with definitions evolving from ancient philosophical ideas to modern genetics and systems biology.