Juvenile (organism) in the context of "Nekton"

Marine microorganisms are defined by their habitat as microorganisms living in a marine environment, that is, in the saltwater of a sea or ocean or the brackish water of a coastal estuary. A microorganism (or microbe) is any microscopic living organism or virus, which is invisibly small to the unaided human eye without magnification. Microorganisms are very diverse. They can be single-celled or multicellular and include bacteria, archaea, viruses, and most protozoa, as well as some fungi, algae, and animals, such as rotifers and copepods. Many macroscopic animals and plants have microscopic juvenile stages. Some microbiologists also classify viruses as microorganisms, but others consider these as non-living.

Marine microorganisms have been variously estimated to make up between 70 and 90 percent of the biomass in the ocean. Taken together they form the marine microbiome. Over billions of years this microbiome has evolved many life styles and adaptations and come to participate in the global cycling of almost all chemical elements. Microorganisms are crucial to nutrient recycling in ecosystems as they act as decomposers. They are also responsible for nearly all photosynthesis that occurs in the ocean, as well as the cycling of carbon, nitrogen, phosphorus and other nutrients and trace elements. Marine microorganisms sequester large amounts of carbon and produce much of the world's oxygen.

Oviparous animals are animals that reproduce by depositing unfertilized egg cells or fertilized zygotes outside the body (i.e., by laying or spawning) in metabolically independent incubation organs (eggs), which nurture the embryo into moving offspring (hatchlings) with little or no embryonic development within the mother. This is the reproductive method used by most animal species, as opposed to viviparous animals that develop the embryos internally and metabolically dependent on the maternal circulation, until the mother gives birth to live juveniles.

Ovoviviparity is a special form of oviparity where the eggs are retained inside the mother (but still metabolically independent), and are carried internally until they hatch and eventually emerge outside as well-developed juveniles similar to viviparous animals.

A puppy is a juvenile dog, generally one less than 12–18 months old.

Puppies are markedly underdeveloped and dependent on their mothers at birth (displaying altriciality), but healthy puppies grow quickly and begin walking thereafter. Puppies generally weigh 250–450 grams (8–16 oz) shortly after birth, depending on the breed.

In common terminology, a baby is the very young offspring of adult human beings, while infant (from Latin īnfāns 'baby, child') is a formal or specialised synonym. The terms may also be used to refer to juveniles of other organisms. A newborn is, in colloquial use, a baby who is only hours, days, or weeks old; while in medical contexts, a newborn or neonate (from Latin neonātus 'newborn') is an infant in the first 28 days after birth (the term applies to premature, full term, and postmature infants).

Infants born prior to 37 weeks of gestation are called "premature", those born between 39 and 40 weeks are "full term", those born through 41 weeks are "late term", and anything beyond 42 weeks is considered "post term".

In animals, viviparity is the development of the embryo inside the body of the mother, with the maternal circulation providing for the metabolic needs of the embryo's development, until the mother gives birth to a fully or partially developed juvenile that is at least metabolically independent. This is opposed to oviparity, where the embryos develop independently outside the mother in eggs until they are developed enough to break out as hatchlings; and ovoviviparity, where the embryos are developed in eggs that remain carried inside the mother's body until the hatchlings emerge from the mother as juveniles, similar to a live birth.

The Denisovans or Denisova hominins (/dəˈniːsəvə/ də-NEE-sə-və) are an extinct species or subspecies of archaic human that ranged across Asia during the Middle to Late Pleistocene, approximately 200,000–32,000 years ago. Most of what is known about Denisovans comes from DNA evidence. While many recent fossils have been found and tentatively identified as Denisovan, the first Denisovans discovered were known from few physical remains. Consequently, no formal species name has been established. However, an analysis of the mitochondrial DNA and endogenous proteins from the Harbin cranium, which had been given the name Homo longi, showed with great certainty that this species represents a Denisovan.In a study published in September 2025, remains from six additional sites in China including the 1 million year old Yunxian man were proposed to be included in the species Homo longi along with the genetically confirmed Denisovans.

The first identification of a Denisovan individual occurred in 2010, based on mitochondrial DNA (mtDNA) extracted from a juvenile finger bone excavated from the Siberian Denisova Cave in the Altai Mountains in 2008. Nuclear DNA indicates close affinities with Neanderthals. The cave was also periodically inhabited by Neanderthals. Additional specimens from Denisova Cave were subsequently identified, as were specimens from the Baishiya Karst Cave on the Tibetan Plateau, Tam Ngu Hao 2 Cave in the Annamite Mountains of Laos, the Penghu channel between Taiwan and the mainland, and Harbin in Manchuria.