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Migration, in
ecology Ecology (from el, οἶκος, "house" and el, -λογία, label=none, "study of") is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers at the individual, , , , an ...
, is the large-scale movement of members of a species to a different
environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...

environment
. Migration is a natural behavior and component of the
life cycle Life cycle, life-cycle, or lifecycle may refer to: Science and academia *Biological life cycle, the sequence of life stages that an organism undergoes from birth to reproduction ending with the production of the offspring *Life-cycle hypothesis, ...
of many species of mobile organisms, not limited to animals, though
animal migration Animal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of Migration (ecology), migration in ecology. It is found in all major animal groups, including Bird migration ...
is the best known type. Migration is often cyclical, frequently occurring on a
season A season is a division of the year based on changes in weather Weather is the state of the atmosphere, describing for example the degree to which it is hot or cold, wet or dry, calm or stormy, clear or cloud cover, cloudy. On Earth, most ...

season
al basis, and in some cases on a daily basis. Species migrate to take advantage of more favorable conditions with respect to
food Food is any substance consumed to provide nutritional Nutrition is the biochemical Biochemistry or biological chemistry, is the study of chemical processes within and relating to living organism In biology, an organism (from Anci ...

food
availability, safety from
predation Predation is a biological interaction In ecology Ecology (from el, οἶκος, "house" and el, -λογία, label=none, "study of") is the study of the relationships between living organisms, including humans, and their physical env ...

predation
,
mating In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular biology, molecular interactions, Physiology, physiological mechanism ...

mating
opportunity, or other environmental factors. While members of some species learn a migratory route on their first journey with older members of their group, other species genetically pass on information regarding their migratory paths. Despite many differences in organisms’ migratory cues and behaviors, “considerable similarities appear to exist in the cues involved in the different phases of migration.” Migratory organisms use environmental cues like
photoperiodPhotoperiodism is the physiological reaction of organisms to the length of night or a dark period. It occurs in plants and animals. Photoperiodism can also be defined as the developmental responses of plants to the relative lengths of light and dark ...
and weather conditions as well as internal cues like hormone levels to determine when it is time to begin a migration. Migratory species use senses such as
magnetoreception Magnetoreception (also magnetoception) is a sense A sense is a biological system used by an organism for sensation, the process of gathering information about the world and responding to Stimulus (physiology), stimuli. (For example, in the hu ...
or
olfaction The sense of smell, or olfaction, is the special sense In medicine Medicine is the Art (skill), art, science, and Praxis (process) , practice of caring for a patient and managing the diagnosis, prognosis, Preventive medicine, prevention, ther ...
to orient themselves or navigate their route, respectively. The factors that determine migration methods are variable due to the inconsistency of major seasonal changes and events. When an organism migrates from one location to another, its energy use and rate of migration are directly related to each other and to the safety of the organism. If an ecological barrier presents itself along a migrant's route, the migrant can either choose to use its energy to cross the barrier directly or use it to move around the barrier. If an organism is migrating to a place where there is high competition for food or habitat, its rate of migration should be higher. This indirectly helps determine an organism's fitness by increasing the likelihood of its survival and reproductive success. Migration is most commonly seen as animal migration, the physical movement by animals from one area to another. That includes
bird Birds are a group of s constituting the Aves , characterised by s, toothless beaked jaws, the of eggs, a high rate, a four-chambered , and a strong yet lightweight . Birds live worldwide and range in size from the to the . There ar ...
,
fish Fish are , , -bearing animals that lack with . Included in this definition are the living , s, and and as well as various extinct related groups. Around 99% of living fish species are ray-finned fish, belonging to the class , with over 95 ...
, and
insect migration Insects or Insecta (from Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power ...
. However, plants can be said to migrate, as
seed dispersal Seed dispersal is the movement, spread or transport of seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The ban ...
enables plants to grow in new areas, under environmental constraints such as temperature and rainfall. When those constraints change, the border of a plant species's distribution may move, so the plant may be said to migrate, as for example in forest migration.


Effects of migration

A species migrating to a new community can affect the outcome of local competitive interactions. A species that migrates to a new community can cause a top-down effect within the community. If the migratory species is abundant in the new community, it can become a main prey for a resident predator, leaving other resident species as only an alternate prey. This new source of food (migrants) can increase the predatory species’ population size, impacting population sizes of its other prey when the migratory species return to their original location. If a resident species experiences a scarcity of food due to seasonal variation, the species can decrease in population, creating an opportunity for a new species to migrate to that location as the decrease in the population of the resident species leaves an abundance of food. Migratory species can also transport diseases long-distance from their original habitat.


See also

*
Great American Interchange The Great American Biotic Interchange (commonly abbreviated as GABI), also known as the Great American Interchange or Great American Faunal Interchange, was an important late Cenozoic The Cenozoic ( ; ) is Earth's current geological era An er ...
, an event in which fauna migrated between North America and South America one the continents were bridged by the Isthmus of Panama *
Human migration Human migration involves the movement of people from one place to another with intentions of settling, permanently or temporarily, at a new location (geographic region). The movement often occurs over long distances and from one country ...

Human migration
, physical movement by humans from one area to another


References

{{reflist Ecology Broad-concept articles