#life cycle

• Aphagous — A biological term used to describe an organism or animal that, during a specific stage of its life cycle or biological development, does not feed at all. The phenomenon is frequently encountered among certain insects in their adult (imago) or pupal stage, where the mouthparts are atrophied, their exclusive function being reproduction, with energy provided by reserves accumulated during previous larval phases.
• Amphibian — A poikilothermic vertebrate, structurally adapted to a dual aquatic and terrestrial way of life, belonging to the class Amphibia. In the larval stage (tadpole), it breathes through gills and lives exclusively in water, while as an adult, it develops lungs and cutaneous respiration, adapting to the land environment; as an adjective, it describes an organism, military vehicle, or technical apparatus capable of operating both on land and on water.
• Anadromous — Said of fish or marine species that normally live in seas or oceans but structurally migrate into the fresh waters of rivers to spawn and reproduce. This complex biological behavior, specific to species like salmon, sturgeons, or Pontic shad, involves major physiological and osmoregulatory adaptations to tolerate the abrupt transition from marine salinity to fresh water.
• Anaerobiont — A microorganism or lower organism that lives and structurally develops exclusively in an environment devoid of free molecular oxygen. This type of organism, primarily represented by denitrifying, methanogenic, or sulfate-reducing bacteria, obtains the energy required for its vital functions through alternative metabolic processes such as fermentation or anaerobic respiration.
• Androspore — A specialized asexual male spore (found in certain green algae belonging to the Oedogoniales order) which, upon release and attachment to a female plant, structurally germinates to produce a dwarf male filament, a structure subsequently responsible for producing antherozoids.
• Anogramma — A genus of small, terrestrial ferns in the Pteridaceae family, characterized by finely dissected fronds and an annual or ephemeral lifecycle unusual for pteridophytes. The best-known species is Anogramma leptophylla, a unique structural plant that survives from year to year primarily as a perennial tuberous gametophyte, colonizing damp, shaded, rocky soils in Mediterranean and temperate climates.
• Anogramma leptophylla — A unique species of small fern in the Pteridaceae family, remarkable for its annual or ephemeral life cycle, an atypical phenomenon among pteridophytes. The plant possesses thin, delicate, translucent fronds, but its ultimate structural feature is that the sporophyte regularly dies off during the dry season, survival from year to year being secured by a perennial tuberous gametophyte colonizing shaded rocky niches in Mediterranean and temperate zones.