Terrestrial animal

Terrestrial animal

Terrestrial animals are animals that live predominantly or entirely on land, as compared with aquatic animals, which live predominantly or entirely in the water (e.g., fish, lobsters, octopuses), or amphibians, which rely on a combination of aquatic and terrestrial habitats (e.g., frogs). Terrestrial animals evolved from marine animals (aquatic animals living in the ocean). The term terrestrial is also frequently used for species that live primarily on the ground, in contrast to arboreal species, which live primarily in trees.

Taxonomy

Terrestrial animals do not form a unified clade, rather they share only the fact that they live on land. The transition from an aquatic to terrestrial life has evolved independently and successfully many times by various groups of animals.

When excluding internal parasites, free living species in terrestrial environments are represented by the following ten phyla; Flatworms (Planaria), Nemertea (ribbon worms), Nematoda (roundworms), Rotifers, Tardigrada (water bears), Onychophora (velvet worms), Arthropods, mollusks (gastropods), Annelida and Chordata (tetrapods). The roundworms, tardigrades and rotifers are microscopic animals that requires a film of water to live in, and are not considered truly terrestrial. Flatworms, ribbon worms, velvet worms and annelids all depends on more or less moist habitats, while the three remaining categories, arthropods, gastropods and tetrapods, are the only ones that contain species that have been able to adapt to predominantly dry terrestrial environments.

Difficulties

Labeling an animal species "terrestrial" or "aquatic" is often obscure and becomes a matter of judgment.

Many animals which are considered terrestrial have a life-cycle that is partly dependent on being in water. Penguins, seals and walruses sleep on land and feed in the ocean, yet they are all considered terrestrial. Many insects and all terrestrial crabs (as well as other clades) have an aquatic life cycle stage: their eggs need to be laid in and to hatch in water. After hatching there is an early aquatic form, either a nymph or larva.

There are crab species which are completely aquatic, crab species which are amphibious, and crab species which are terrestrial. Fiddler crabs are called “semi-terrestrial” since they make burrows in the muddy substrate to which they retreat during high tides. When the tide is out, fiddler crabs search the beach for food.

The same is true in the Mollusca: many hundreds of gastropod genera and species live in intermediate situations, such as for example, Truncatella. Some gastropods with gills live on land, and others with a lung live in the water.

As well as the purely terrestrial and the purely aquatic animals there are many borderline species. There are no universally accepted criteria for deciding how to label these species.

Notes


Wikimedia Foundation. 2010.

Игры ⚽ Поможем написать курсовую

Look at other dictionaries:

  • Terrestrial — refers to things having to do with the land or the Earth.Related terms* Extra Terrestrial, the sloven hore next door * Terrestrial animal, an animal that lives on the land, as opposed to in water, air, or in the trees * Terrestrial plant, a plant …   Wikipedia

  • terrestrial — [[t]tɪre̱striəl[/t]] 1) ADJ: usu ADJ n A terrestrial animal or plant lives on land or on the ground rather than in the sea, in trees, or in the air. [TECHNICAL] Terrestrial and aquatic fauna may sometimes be found resting together under a loose… …   English dictionary

  • Animal Collective — en concert à Prague en 2008 Pays d’origine …   Wikipédia en Français

  • Animal Collective — Saltar a navegación, búsqueda Animal Collective Información personal Origen Baltimore, Maryland (EE.UU.) Información artística Géner …   Wikipedia Español

  • Animal Collective — Жанры Экспериментальный рок, инди рок, нойз Годы 1999 наши дни Страна …   Википедия

  • terrestrial — ► ADJECTIVE 1) of, on, or relating to the earth or dry land. 2) (of an animal or plant) living on or in the ground. 3) (of television broadcasting) using ground based equipment rather than a satellite. ► NOUN ▪ an inhabitant of the earth.… …   English terms dictionary

  • animal — animalic /an euh mal ik/, animalian /an euh may lee euhn, mayl yeuhn/, adj. /an euh meuhl/, n. 1. any member of the kingdom Animalia, comprising multicellular organisms that have a well defined shape and usually limited growth, can move… …   Universalium

  • animal development — Introduction  the processes that lead eventually to the formation of a new animal starting from cells derived from one or more parent individuals. Development thus occurs following the process by which a new generation of organisms is produced by …   Universalium

  • Terrestrial locomotion — [ horse an erect stanced unguligrade quadruped with a galloping gait. An animation of photos by Eadweard Muybridge] Terrestrial locomotion has evolved as animals adapted from aquatic to terrestrial environments. Locomotion on land raises… …   Wikipedia

  • Animal locomotion — In biomechanics, animal locomotion is the study of how animals move. Not all animals move, but locomotive ability is widespread throughout the animal kingdom. As all animals are heterotrophs, they must obtain food from their environment. Some… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”