natality
204
of cock on either side. The Nansen bottle is tripped by a messenger weight that
is slipped along the cable, and the closing occurs when the upper one of the
clamps by which the apparatus is attached to the cable loosens and the Nansen
turns upside down. This may also fixate a reversing thermometer that can be
attached to the instrument, so that a water sample and a temperature observation are obtained simultaneously. It is possible to attach more than one
Nansen bottle to a cable, and so obtain a series of samples in one so-called cast.
natality (syn. birth rate) number of new born individuals entering a population
per individual member per unit of time. ~population parameters.
natural mortality ~mortality.
natural selection the key factor in Darwin's evolution theory. Survival of the
fittest: depending on environmental conditions certain types of juveniles or
adults have a lower mortality than others with different genomes, so due to a
larger reproduction the frequency of certain genes within the population
will rise. New, favorable, mutants may change the species. ~evolution.
nauplius development stage occurring in many Crustacea species. There are six
naupliar stages (n1-n6). The larva is oval, unsegmented and has three pairs
of appendages, which increase in complexity from n1 to n6. In Copepoda, the
nauplius changes into a copepodite; in Malacostraca into a zoea.
Nauplius.
(After Bj0rnberg 1972)
nautical mile (syn. sea mile) one-sixtieth part of a degree at the equator. The UK
nautical mile is 1853.18 m, while the international nautical mile is 1852 m.
Navier-Stokes equation the equation of motion in its most elementary form.
~hydrodynamics.
204
of cock on either side. The Nansen bottle is tripped by a messenger weight that
is slipped along the cable, and the closing occurs when the upper one of the
clamps by which the apparatus is attached to the cable loosens and the Nansen
turns upside down. This may also fixate a reversing thermometer that can be
attached to the instrument, so that a water sample and a temperature observation are obtained simultaneously. It is possible to attach more than one
Nansen bottle to a cable, and so obtain a series of samples in one so-called cast.
natality (syn. birth rate) number of new born individuals entering a population
per individual member per unit of time. ~population parameters.
natural mortality ~mortality.
natural selection the key factor in Darwin's evolution theory. Survival of the
fittest: depending on environmental conditions certain types of juveniles or
adults have a lower mortality than others with different genomes, so due to a
larger reproduction the frequency of certain genes within the population
will rise. New, favorable, mutants may change the species. ~evolution.
nauplius development stage occurring in many Crustacea species. There are six
naupliar stages (n1-n6). The larva is oval, unsegmented and has three pairs
of appendages, which increase in complexity from n1 to n6. In Copepoda, the
nauplius changes into a copepodite; in Malacostraca into a zoea.
Nauplius.
(After Bj0rnberg 1972)
nautical mile (syn. sea mile) one-sixtieth part of a degree at the equator. The UK
nautical mile is 1853.18 m, while the international nautical mile is 1852 m.
Navier-Stokes equation the equation of motion in its most elementary form.
~hydrodynamics.