organizmem

Organizmem is a term used in some languages to denote a living organism; the standard English term is organism. An organism is an individual life form that carries out the essential processes of life, including metabolism, growth, response to stimuli, development, and reproduction.

Most organisms are cellular. They can be unicellular, consisting of a single cell, or multicellular, composed of many specialized cells. Organisms are broadly categorized into prokaryotes, which lack a membrane-bound nucleus, and eukaryotes, which possess a nucleus and other organelles. Viruses are sometimes discussed in relation to organisms but are not universally regarded as living organisms because they lack independent metabolism.

In multicellular organisms, organization occurs at several levels: cells form tissues, tissues compose organs, and organs interact within organ systems to sustain the organism’s life. Single-celled organisms perform all necessary functions within one cell. All known organisms rely on energy capture and transformation to maintain homeostasis and support growth.

Organisms reproduce to pass on genetic information. Reproduction can be asexual, producing offspring genetically similar to the parent, or sexual, involving fusion of genetic material from two parents. Genetic variation drives evolution through natural selection and adaptation.

Taxonomically, organisms are classified using a hierarchical system that begins with domains and kingdoms and narrows to phyla, classes, orders, families, genera, and species. The three-domain system groups life as Bacteria, Archaea, and Eukarya. Examples include Escherichia coli (a bacterium) and Homo sapiens (humans).