<< Chapter < Page Chapter >> Page >

A similar, but more directed version of kinesis is taxis    : the directed movement towards or away from a stimulus. This movement can be in response to light (phototaxis), chemical signals (chemotaxis), or gravity (geotaxis) and can be directed toward (positive) or away (negative) from the source of the stimulus. An example of a positive chemotaxis is exhibited by the unicellular protozoan Tetrahymena thermophila . This organism swims using its cilia, at times moving in a straight line, and at other times making turns. The attracting chemotactic agent alters the frequency of turning as the organism moves directly toward the source, following the increasing concentration gradient.

Fixed action patterns

A fixed action pattern    is a series of movements elicited by a stimulus such that even when the stimulus is removed, the pattern goes on to completion. An example of such a behavior occurs in the three-spined stickleback, a small freshwater fish ( [link] ). Males of this species develop a red belly during breeding season and show instinctual aggressiveness to other males during this time. In laboratory experiments, researchers exposed such fish to objects that in no way resemble a fish in their shape, but which were painted red on their lower halves. The male sticklebacks responded aggressively to the objects just as if they were real male sticklebacks.

Photo shows a white fish with a reddish bottom on top. Below the fish is a diamond-shaped object that resembles a fishing lure; it is white on the top and red on the bottom, with an eye at the front.
Male three-spined stickleback fish exhibit a fixed action pattern. During mating season, the males, which develop a bright red belly, react strongly to red-bottomed objects that in no way resemble fish.

Migration

Migration is the long-range seasonal movement of animals. It is an evolved, adapted response to variation in resource availability, and it is a common phenomenon found in all major groups of animals. Birds fly south for the winter to get to warmer climates with sufficient food, and salmon migrate to their spawning grounds. The popular 2005 documentary March of the Penguins followed the 62-mile migration of emperor penguins through Antarctica to bring food back to their breeding site and to their young. Wildebeests ( [link] ) migrate over 1800 miles each year in search of new grasslands.

Photo shows a heard of wildebeests crossing a river.
Wildebeests migrate in a clockwise fashion over 1800 miles each year in search of rain-ripened grass. (credit: Eric Inafuku)

Although migration is thought of as innate behavior, only some migrating species always migrate (obligate migration). Animals that exhibit facultative migration can choose to migrate or not. Additionally, in some animals, only a portion of the population migrates, whereas the rest does not migrate (incomplete migration). For example, owls that live in the tundra may migrate in years when their food source, small rodents, is relatively scarce, but not migrate during the years when rodents are plentiful.

Foraging

Foraging is the act of searching for and exploiting food resources. Feeding behaviors that maximize energy gain and minimize energy expenditure are called optimal foraging behaviors, and these are favored by natural section. The painted stork, for example, uses its long beak to search the bottom of a freshwater marshland for crabs and other food ( [link] ).

Questions & Answers

what is nutrition
Joseph Reply
the process of providing or obtaining the food necessary for health and growth.
fatimah
what are micro-organism
Bukiwe Reply
what is immunity
Moriba Reply
What is cross pollination
Moriba
what is pollution
Georgiana Reply
what is pollution
Georgiana
list four type of biological association
Georgiana
Pollution is the release of harmful substances in the atmosphere.
Immanuel
Four biological associations are 1) commensalism 2)symbiosis 3)mutualism 4) parasitism
Immanuel
What is the function of the hormones
Immanuel Reply
What is the other name of filament of a flower
Immanuel
oxygen
Georgiana
list three bone disorders and explain them
Blessings Reply
oxygen
Georgiana
what is self pollination?
Kelvin Reply
well, self-pollination occurs in a single flower which has the organs of both genders. the pollen grains from the anther shall be captured by the stigma of the flower, when released. and the pollen grain shall start grow pollen tube which grows down in the style, to the ovary, ovules and the
Izzati
insides of the ovules. so pretty much the pollen grains being pollinated from the anther to the stigma of the same flower
Izzati
I think
Izzati
the pollen grains being pollinated from the anther to the stigma of the same flower
Izzati
what is animal science
Rose Reply
Animal science is described as "studying the biology of animals that are under the control of humankind".
AMIIRA
don't you guys have Google
Izzati
what is self pollinating
JOSHUA Reply
what is cleistogamy
JOSHUA
Self pollination occurs when the pollen from the anther is deposited on the stigma of the same flower, or another flower on the same plant.
Franklina
Cleistogamy is a type of automatic self pollination of certain plants that can propagate by using non opening, self pollinating flowers
Franklina
Self pollination is the transfer of pollen grain from the anther to the stigma
Immanuel
who is the father of biology
Sean Reply
Aristotle
Lubera
Aristotle
estella
yes Aristotle looking at classification
John
Aristotle
JOSHUA
Aristotle
Grace
please my answer
Sean
Aristotle
Rose
Aristotle
Immanuel
what are prokaryotic cells
Kusubira Reply
having cell that lack membrane - bound nuclei.
Lubera
Pronkayotic cells are cells that lacks nuclear membrane
Immanuel
Please each person should suggest ur answers
Franklina Reply
differentiate between autelogical and synecology
Christiana Reply
differentiate between autelogical and synecology
Christiana Reply
answer please
Edmond
Autecology is the study of individual organism or individual species. It is also known as population ecology. Synecology is the study of group of organisms of different species which are associated together as a unit in form of a community.
Daniel
Autecology is the study of the environment in relation to only one species in contrast while synecology is the study of the environment affecting groups of species coexisting in an area.
Franklina
Describe the factors affecting homotasis
Grace Reply
Fluids and electrolytes Energy and nutrition Immune response mediators
Franklina

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Biology. OpenStax CNX. Feb 29, 2016 Download for free at http://cnx.org/content/col11448/1.10
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Biology' conversation and receive update notifications?

Ask