Obligate means "by necessity" (antonym facultative) and is used mainly in biology in phrases such as:

  • Obligate aerobe, an organism that cannot survive without oxygen
  • Obligate anaerobe, an organism that cannot survive in the presence of oxygen
  • Obligate air-breather, an organism dependent on oxygen respired directly from the atmosphere rather than extracted from solution in water, for example, the South American lungfish
  • Obligate carnivore, a true carnivore — dependent for survival on a diet of animal flesh.
  • Obligate intracellular parasite, a parasitic microorganism that cannot reproduce without entering a suitable host cell
  • Obligate parasite, a parasite that cannot reproduce without exploiting a suitable host
  • Obligate photoperiodic plant, a plant that requires sufficiently long or short nights before it initiates flowering, germination or similarly functions
  • Obligate symbionts, organisms that can only live together in a symbiosis
  • Obligate hibernation, a state of inactivity in which some organisms survive conditions of insufficiently available resources.

Other articles related to "obligate":

Intracellular Parasite - Obligate
... Obligate intracellular parasites cannot reproduce outside their host cell, meaning that the parasite's reproduction is entirely reliant on intracellular resources ... Obligate intracellular parasites of humans include viruses Certain bacteria, including Chlamydia, and closely related species ... Study of obligate pathogens is difficult because they cannot usually be reproduced outside the host ...
Prodoxidae - Yucca Moths
... with Yucca plants and are their obligate pollinators as well as herbivores (Pellmyr et al ... Interactions of these organisms range from obligate mutualism to commensalism to outright antagonism ... moth genera in particular, Tegeticula and Parategeticula, have an obligate pollination mutualism with yuccas ...
Obligate Parasite
... An obligate parasite is a parasitic organism that cannot complete its life cycle without exploiting a suitable host ... If an obligate parasite cannot obtain a host it will fail to reproduce ... Obligate parasites have evolved a variety of parasitic strategies to exploit their hosts ...
Obligation - Other Uses
... The term obligate can also be used in a biological context, in reference to species which must occupy a certain niche or behave in a certain way in order to survive ... In biology, the opposite of obligate is facultative, meaning that a species is able to behave in a certain way and may do so under certain circumstances, but that it can also survive without having to behave ... For example, species of salamanders in the family Proteidae are obligate paedomorphs, whereas species belonging to the Ambystomatidae are facultative paedomorphs ...