Facultative vs. Obligate
Main DifferenceThe main difference between Facultative and Obligate is that the Facultative organisms can obtain energy from any three methods of respiration that are aerobic respiration, anaerobic respiration, and fermentation, whereas Obligate organisms can get energy from only one process of respiration that is aerobic respiration, anaerobic respiration, or fermentation.

Difference Between Facultative and Obligate
Facultative vs. Obligate
The facultative parasite can live independently in half of its life; on the other hand, the obligate parasite cannot live as independently.
Facultative vs. Obligate
The facultative parasite can live without the host, while obligate cannot live without a host.
Facultative vs. Obligate
Facultative organisms can survive in more than one specific condition; on the opposite side; the obligate parasite can survive in a particular situation.
Facultative vs. Obligate
The efficiency of energy production is very high in the facultative organism, whereas the ability of energy production is deficient in the obligate parasite.
Facultative vs. Obligate
The facultative organism can survive in the absence of oxygen; on the other hand, the obligate organism cannot survive in the lack of oxygen.
Facultative vs. Obligate
Facultative organisms can live inside or outside the host; on the flip side, obligate organisms can live only in the host.
Facultative vs. Obligate
Facultative organisms include the only single type that is facultative anaerobes; on the other side of the coin, obligate organisms include two types that are obligate aerobes and obligate anaerobes.
Facultative vs. Obligate
Facultative organisms can obtain energy from any three methods of respiration that are aerobic respiration, anaerobic respiration, and fermentation, whereas obligate organisms can get energy from only one process of respiration that is aerobic respiration, anaerobic respiration, or fermentation.
Facultative vs. Obligate
Facultative organisms are found throughout the liquid medium but mostly near the surface of the medium; on the other hand, obligate aerobes are found near the surface, whereas obligate anaerobes are found at the bottom of the liquid medium.
Facultativeadjective
Of or relating to faculty, especially to mental faculty
Obligateverb
To bind, compel, constrain, or oblige by a social, legal, or moral tie.
Facultativeadjective
Not obligate; optional, discretionary or elective
Obligateverb
To cause to be grateful or indebted; to oblige.
Facultativeadjective
That grants permission or power to do something
Obligateverb
To commit (money, for example) in order to fulfill an obligation.
Facultativeadjective
(biology) Able to perform a particular life function, or to live generally, in more than one way
Obligateadjective
(biology) Able to exist or survive only in a particular environment or by assuming a particular role.
an obligate parasitean obligate anaerobeFacultativeadjective
At which a given function is positive.
Obligateadjective
Absolutely indispensable; essential.
Facultativeadjective
of or relating to the mental faculties
Obligateverb
force or compel somebody to do something;
We compel all students to fill out this formFacultativeadjective
able to exist under more than one set of conditions;
a facultative parasite can exist as a parasite or a saprophyteObligateverb
commit in order to fulfill an obligation;
obligate moneyFacultativeadjective
granting a privilege or permission or power to do or not do something;
a facultative enactmentObligateverb
bind by an obligation; cause to be indebted;
He's held by a contractI'll hold you by your promiseFacultativeadjective
not compulsory;
facultative courses in the sciencesObligateadjective
restricted to a particular condition of life;
an obligate anaerobe can survive only in the absence of OXYGenComparison Chart
Facultative | Obligate |
Facultative organisms can obtain energy from any three methods of respiration that are aerobic respiration, anaerobic respiration, and fermentation | Obligate organisms can get energy from only one process of respiration that is aerobic respiration, anaerobic respiration, or fermentation |
Condition | |
It can live in more than one specific conditions | It can live only a particular condition |
Types | |
It includes only one type that is facultative anaerobes | It consists of two types that are known as obligate aerobes and obligate anaerobes |
Importance of Oxygen | |
It can live in the presence or absence of oxygen | It cannot live in the lack of oxygen |
Habitat | |
It can live inside and outside of the host | Obligate anaerobes can live only inside the host, and obligate aerobes live outside the host |
Parasites | |
Facultative parasites can live without the host | Obligate parasites cannot live without the host |
In a Liquid Medium | |
It is present throughout the medium but mostly near the surface | Obligate aerobes are found near the surface of a liquid medium, and obligate anaerobes are found at the bottom of the liquid medium |
The Efficiency of Energy Production | |
It has high energy production efficiency | It has low energy production efficiency |
Facultative vs. Obligate
A facultative organism can live in more than one particular habitats, while the obligate organism can live only in one specific environment. Facultative organisms can obtain energy from any three methods of respiration that are aerobic respiration, anaerobic respiration, and fermentation, whereas obligate organisms can get energy from only one way of respiration that is aerobic respiration, anaerobic respiration, or fermentation. The efficiency of energy production in facultative is high, whereas the energy production in obligate is low.
Facultative organism includes only one type that is known as facultative anaerobes, while obligate organism consists of two types that are identified as obligate aerobes and obligate anaerobes. Facultative organisms can live with or without the excess of oxygen; on the other side, obligate organisms cannot live without the excess of oxygen. All the facultative organisms can survive in both the external and internal environments of the host; on the other hand, obligate anaerobes can live only inside the host and obligate aerobes to live outside the host in the external environment.
Facultative parasites spend their half-life as a parasite and half as an independent, whereas obligate parasite spends their whole life as a parasite. A facultative parasite can live without the host; on the other side of the coin, obligate parasites cannot live without the host. Facultative organisms are mainly present throughout the liquid medium but almost near the surface, while obligate anaerobes are present at the bottom of the liquid medium, and obligate aerobes are present near the surface of the liquid medium.
What is Facultative?
Facultative organisms are organisms that can produce their energy. It can live without the oxygen, but if the oxygen is present in the medium, then it can utilize it. Facultative organisms can live in more than one specific condition. It can produce its energy by any of the three methods, such as aerobic respiration, anaerobic respiration, and fermentation.
It can also live without the host and can spend most of its life as independently. Facultative organisms contain only a single type known as facultative anaerobes. Facultative anaerobes are found near the surface of the liquid medium. It includes facultative fungi, facultative bacteria, and facultative protozoans.
What is Obligate?
Obligate organisms are organisms that cannot produce their energy. That’s why its energy production efficiency is very low. It also cannot survive in the absence of an excess of oxygen. The obligate parasite can live only in specific conditions. It can produce its energy only by one of the three methods, such as aerobic respiration, anaerobic respiration, and fermentation.
Obligate organisms include two types that are obligate aerobes and obligate anaerobes. Obligate aerobes can live only inside the host, and obligate anaerobes can live outside the host. It spends all of its life as a parasite. Obligate aerobes are found at the surface of the liquid medium, whereas obligate anaerobes are found at the bottom of the liquid medium. It includes obligate fungi, obligate bacteria, obligate protozoa.
ConclusionThe above discussion concludes the main difference between the facultative and obligate organisms is the type of cellular respiration occur in them. Facultative organisms have only one type known as facultative anaerobes; on the other hand, obligate organisms have two types known as obligate aerobes and anaerobes.