Related topics: cells · protein · bacteria · genes · mutations

Could Earth life survive on a red dwarf planet?

Even though exoplanet science has advanced significantly in the last decade or two, we're still in an unfortunate situation. Scientists can only make educated guesses about which exoplanets may be habitable. Even the closest ...

A new lexicon in the age of microbiome research

Over the past 20 years, life science research has come to realize that all living beings—from the simplest animal and plant organisms to humans—live in close association with a large number of microorganisms. Together ...

Pesticide-free as a new pathway for agriculture

A new approach is gaining momentum in European agriculture: a "third way" that lies between conventional production and organic farming systems. Here farmers must forego synthetic pesticides only—which is simpler to implement ...

Astronomers propose a 50-meter submillimeter telescope

Some parts of the universe only reveal important details when observed in radio waves. That explains why we have ALMA, the Atacama Large Millimeter–submillimeter Array, a collection of 7-meter and 12-meter radio telescopes ...

Sea anemones study reveals insights into predator-prey dynamics

A new study reveals crucial insights into animal defense mechanisms and tradeoffs. The surprising discovery of a native anemone population lacking the Nv1 neurotoxin led to an investigation into its impact on defending against ...

Why eukaryotes, not bacteria, evolved complex multicellularity

Prokaryotic single-celled organisms, the ancestors of modern-day bacteria and archaea, are the most ancient form of life on our planet, first appearing roughly 3.5 billion years ago. The first eukaryotic cells appeared around ...

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Organism

In biology, an organism is any living system (such as animal, plant, fungus, or micro-organism). In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homeostasis as a stable whole. An organism may either be unicellular (single-celled) or be composed of, as in humans, many billions of cells grouped into specialized tissues and organs. The term multicellular (many-celled) describes any organism made up of more than one cell.

The terms "organism" (Greek ὀργανισμός - organismos, from Ancient Greek ὄργανον - organon "organ, instrument, tool") first appeared in the English language in 1701 and took on its current definition by 1834 (Oxford English Dictionary).

Scientific classification in biology considers organisms synonymous with life on Earth. Based on cell type, organisms may be divided into the prokaryotic and eukaryotic groups. The prokaryotes represent two separate domains, the Bacteria and Archaea. Eukaryotic organisms, with a membrane-bounded cell nucleus, also contain organelles, namely mitochondria and (in plants) plastids, generally considered to be derived from endosymbiotic bacteria. Fungi, animals and plants are examples of species that are eukaryotes.

More recently a clade, Neomura, has been proposed, which groups together the Archaea and Eukarya. Neomura is thought to have evolved from Bacteria, more specifically from Actinobacteria.

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