A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different
A resource is a source or supply from which a benefit is produced and that has some utility. Resources can broadly be classified upon their availability — they are classified into renewable and non-renewable resources. They can also be classif ...
(for example, a
A heterotroph (; from Ancient Greek
Ancient Greek includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following perio ...
with a varied diet
). A specialist species can thrive only in a narrow range of environmental conditions or has a limited diet. Most
In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embodies the Life#Biology, properties of life. It is a synonym for "Outline of life forms, life form".
s do not all fit neatly into either group, however. Some species are highly specialized (the most extreme case being monophagous, eating one specific type of food
), others less so, and some can tolerate many different environments. In other words, there is a continuum from highly specialized to broadly generalist species.
An omnivore () is an animal
Animals (also called Metazoa) are multicellular eukaryotic organisms that form the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular ...
s are usually generalists.
250px, Tracks made by terrestrial gastropods with their radulas, scraping green algae from a surface inside a greenhouse">alga.html" ;"title="radulas, scraping green alga">radulas, scraping green algae from a surface inside a greenhouse
A her ...
s are often specialists, but those that eat a variety of plants may be considered generalists. A well-known example of a specialist animal is the monophagous
The koala or, inaccurately, koala bear (''Phascolarctos cinereus''), is an arboreal herbivorous marsupial native to Australia. It is the only extant representative of the family Phascolarctidae and its closest living relatives are the ...
, which subsists almost entirely on
''Eucalyptus'' () is a genus of over seven hundred species of Flowering plant, flowering trees, shrubs or Mallee (habit), mallees in the Myrtaceae, myrtle Family (biology), family, Myrtaceae. Along with several other genera in the Tribe (biology), ...
The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a medium-sized mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body w ...
is a generalist, because it has a natural range that includes most of North and Central America, and it is omnivorous, eating
A berry is a small, pulpy, and often edible fruit
In botany, a fruit is the seed-bearing structure in flowering plants (also known as angiosperms) formed from the ovary after flowering.
Fruits are the means by which angiosperms dissem ...
, insects such as butterflies, eggs, and various small animals.
The distinction between generalists and specialists is not limited to animals. For example, some plants require a narrow range of temperatures, soil conditions and
Meteorology is a branch of the atmospheric sciences which includes atmospheric chemistry and atmospheric physics, with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant p ...
to survive while others can tolerate a broader range of conditions. A
A cactus (plural cacti, cactuses, or less commonly, cactus) is a member of the plant
Plants are mainly multicellular organisms, predominantly photosynthetic
Photosynthesis is a process used by plants and other organisms to Energy ...
could be considered a specialist species. It will die during winters at high
In geography, latitude is a geographic coordinate that specifies the north– south position of a point on the Earth's surface. Latitude is an angle (defined below) which ranges from 0° at the Equator to 90° (North or South) at the poles. L ...
s or if it receives too much water.
Human body weight refers to a person's mass or weight. Body weight is measured in kilogram
The kilogram (also kilogramme) is the base unit of mass in the International System of Units (SI), the current metric system, having the unit symbol kg ...
is controlled for, specialist feeders such as
A robber fly eating a hoverfly
The giant anteater, a large insectivorous mammal
An insectivore is a carnivorous plant or animal that eats insect
Insects or Insecta (from Latin
Latin (, or , ) is a classical language belonging to ...
A alt=A Bornean orangutan is seen perched on a tree eating a fruit.
A frugivore is an animal that thrives mostly on raw fruits, succulent fruit-like vegetables, roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. ...
s have larger
home rangeA home range is the area in which an animal lives and moves on a periodic basis. It is related to the concept of an animal's territory which is the area that is actively defended. The concept of a home range was introduced by W. H. Burt in 1943. He ...
s than generalists like some
In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds.Jones, S., Martin, R., & Pilbeam, D. (199 ...
s (leaf eaters). who's food source is less abundant, they need a bigger area for
Foraging is searching for wild food resources. It affects an animal's fitness because it plays an important role in an animal's ability to survive and reproduce. Foraging theory is a branch of behavioral ecology that studies the foraging behavi ...
An example comes from the research of Tim Clutton-Brock, who found that the black-and-white colobus, a folivore generalist, needs a home range of only 15 hectare, ha. On the other hand, the more specialized red colobus monkey has a home range of 70 ha, which it requires to find patchy shoots, flowers and fruit.
When environmental conditions change, generalists are able to adapt, but specialists tend to fall victim to extinction much more easily.
[Townsend, C.; Begon, M.; Harper, J. (2003) ''Essentials of Ecology'' (2nd edition) p.54-55 Blackwell, ]
For example, if a species of fish were to go extinct, any specialist parasites would coextinction, also face extinction. On the other hand, a species with a highly specialized ecological niche is more effective at competition (biology), competing with other organisms. For example, a fish and its parasites are in an evolutionary arms race, a form of co-evolution, in which the fish constantly develops defenses against the parasite, while the parasite in turn evolves adaptations to cope with the specific defenses of its host. This tends to drive the speciation of more specialized species provided conditions remain relatively stable. This involves niche partitioning as new species are formed, and biodiversity is increased.
* Cosmopolitan distribution
* Fitness landscape
* List of feeding behaviours