Migration
For the human context, see Human migration |
mtDNA-based chart of large human migrations. |
Migration occurs when living things move from one
biome to another. In most cases organisms migrate to avoid local shortages of food, usually caused by winter. Animals may also migrate to a certain location to breed, as is the case with some
fish.
The species that periodically migrate are called
migratory, those that do not are called
resident (or
sedentary).
Bird migration is common. The longest known migration of a
bird is that of the
Arctic Tern, which migrates from the
Arctic to the
Antarctic and back each year.
Flyways are routes that certain bird species take to migrate.
Whales and other animals, such as
gnus,
butterflies,
moths,
salmon,
eels, and
lemmings are also known to migrate. The periodic migration of plagues of
locusts is a phenomenon recorded since
Biblical times. Occasionally (and usually unexplainedly) an animal may deviate markedly from its customary migration. A widely publicized incident involved
Humphrey the whale, a
humpback whale who errantly entered
San Francisco Bay.
Human migrations also happen on a large scale, in history and in modern times.
Seasonal human migration is very common in agricultural cycles.
In archaeology,
migrationism describes an interpretative framework where all major cultural changes are explained by large-scale movements of people.
Modern transport, particularly the volume and speed of
air transport has facilitated the rapid migration of
bacteria and
viruses which cause diseases. One of the earliest examples is the infamous
plague epidemics or "
Black Death" which arrived in Europe along trade routes via the Middle East from the Orient. More recently, virulent strains of
influenza and
AIDS.
Other types of migration include migration of non-living things such as:
In geophysics, migration is a process which keeps in account the right positions of samples in sections with dipping reflectors and structural complexity.
Piercing migration, where a piece of body
jewelry, during or after healing, shifts or is rejected by the body.
in
Control systems when a set of instructions or
programs, i.e.
PLC (
programmable logic controller) programs, are moved from an old platform to a new. In this way the needed
reengineering can be kept to a minimum.
*
Bird migration*
Fish migration*
Human migration**
Migrant**
Nomadic people**
Seasonal human migration*
Population genetics*
Population transfer*
swuklink.com - Animal Migration*[
1]
