Maarg Manthan · Topic 3.1

Types of Species

Environment & Ecology › Population Ecology and Species Interactions · Topic 3.1

A species is a group of organisms that can interbreed in nature and produce fertile offspring, according to the biological species concept of Ernst Mayr. Ecologists classify species in many ways according to their origin, role and life strategy. By origin, a species is native, indigenous or alien, exotic; a native species occurs naturally in an area, and an alien species has been brought from elsewhere. An endemic species is found only in a particular region, and a cosmopolitan species lives almost worldwide. By ecological role there are keystone, indicator, flagship, umbrella, foundation, dominant and pioneer species. By strategy there are r-selected species that breed fast and K-selected species that breed slowly, and generalists and specialists. By conservation status species are classed as extinct, endangered, vulnerable and so on.

5 min read · UPSC Prelims · Environment & Ecology · Population Ecology and Species Interactions

At a Glance

Origin Native, alien
Range Endemic, cosmopolitan
Role Keystone, flagship, umbrella
Strategy r-selected, K-selected
Concept Biological species, Mayr
Exam link UPSC Prelims, Environment & Ecology: Population Ecology and Species Interactions

Where Does It Fit?

This is the first topic of the macro on population ecology and species interactions. It lists the kinds of species that later topics refer to, such as endemic, keystone and invasive species. Previous topic: Biological Control. Next topic: Population Ecology and Population Growth Models.

How Are Species Classified by Origin and Range?

Type	Meaning and example
Native (indigenous) species	Occurs naturally in an area. Example: Bengal tiger in India
Alien (exotic) species	Introduced into an area where it did not occur naturally. Example: Lantana camara and water hyacinth in India
Invasive species	An alien species that spreads and harms native species or the economy. Example: Parthenium, African catfish
Endemic species	Restricted to one region and found nowhere else. Example: Nilgiri tahr in the Western Ghats, lion-tailed macaque
Cosmopolitan species	Found in most parts of the world. Example: house sparrow, common crow, humans, peregrine falcon
Relict species	Survivors of an earlier age found in small areas, like the Ginkgo tree
Cryptic and sibling species	Species that look alike but are reproductively isolated

How Are Species Classified by Role and Life Strategy?

Keystone species: have a large effect on the ecosystem compared with their numbers, like tigers, elephants and sea otters
Indicator species: show the condition of the environment, like lichens for clean air
Flagship species: charismatic species chosen to attract public support for conservation, such as tiger, panda, one-horned rhinoceros and snow leopard
Umbrella species: species whose habitat needs cover many other species, so protecting them protects others, like tiger and elephant
Foundation species: create or define habitat, such as corals, kelp and mangroves
Dominant and pioneer species: species that control a community, and first colonisers of bare areas
r-selected species: small, short-lived, breed early and produce many offspring with little care, like insects, rodents and weeds; do well in unstable environments
K-selected species: large, long-lived, breed late and produce few offspring with care, like elephants, whales and trees; live near carrying capacity

What Else Should You Remember?

Generalist: uses many resources, like rats and crows
Specialist: uses a narrow set of resources, like koalas
Sympatric species: live in the same area
Allopatric species: live in separate areas
Number of species: about 2 million have been described, and estimates of total are several million
India: occupies 2.4 percent of land but has about 7 to 8 percent of recorded species
Charismatic megafauna: large, appealing animals used in campaigns
Threatened species: critically endangered, endangered and vulnerable
Extinct in the wild: survives only in captivity
Keystone example: figs in tropical forests feed many animals
Ecosystem engineers: beavers, termites and earthworms change habitats
Pollinators: bees and bats, vital for crops
Biological species concept: by Mayr, 1942
Morphological concept: species defined by shape
Phylogenetic concept: species as a branch of a family tree
Species richness hotspots: tropics hold most species
Introduced for use: many alien crops such as potato, maize and tomato are beneficial
Link: endemic, keystone, indicator and invasive species are explained in Endemic Species, Keystone Species, Indicator Species, Invasive Species
Link to niche: species roles are in Habitat and Ecological Niche
Link to speciation: formation of species is in Allopatric and Sympatric Speciation
Caution: the same species may be native in one place and alien in another
Keystone examples in India: elephants shape forests by dispersing seeds and making clearings, and tigers regulate herbivores
Umbrella example: protecting a tiger reserve also protects water catchments, plants and prey species
Pioneer species example: lichens and algae colonise bare rock and water
Species concept limits: the biological concept does not work well for asexual organisms and fossils
Alien benefit and harm: alien crops feed billions while alien weeds and fish damage ecosystems
Charismatic species bias: funding often goes to large attractive animals while small unnoticed species are neglected

Why Does It Matter for the Exam?

Pairs: native versus alien, endemic versus cosmopolitan
Roles: keystone, flagship, umbrella
Strategies: r versus K
Current affairs link: flagship species campaigns
Common errors: mixing flagship with keystone or umbrella species

As an analytical point, choosing the type of species to protect shapes conservation. Flagship species win public support, umbrella species protect habitats, and keystone species protect ecosystem function, so plans use all three ideas.

Why Is This Topic Important?

Origin Native, alien
Role Keystone, flagship
Strategy r and K

What Came Next?

The next topic covers population ecology and population growth models. Next topic: Population Ecology and Population Growth Models.

Key People and Terms

Endemic Found only in one region
Alien species Introduced species
Flagship species Public symbol species
Umbrella species Protects others by habitat
r-selected Many offspring, fast breeding
K-selected Few offspring, slow breeding

Exam Corner

Points to Remember

Endemic example: Nilgiri tahr.
Flagship example: tiger.
r-species: rodents, insects.
K-species: elephant, whale.
Biological species concept: Mayr.

Do Not Confuse With

Flagship and keystone species Public appeal versus ecological effect
Native and endemic species Natural to a place versus only there
r and K species Fast breeders versus slow breeders

Memory Hook

Flagship for fame, umbrella for cover, keystone for function; r runs fast, K lives long.

Mains Angle

Questions ask for definitions and examples. These points help.

Types By origin and role
Strategies r and K
Use Conservation

A Question You May Face

An original practice question, not a past paper question.

“Distinguish between flagship, umbrella and keystone species and explain their use in conservation planning.”

How to Answer

Define Species.
Origin Native, alien.
Role Three types.
Use Planning.

GS Relevance

Prelims: definitions of species types with examples. GS Paper 3: biodiversity and ecology.

Frequently Asked Questions

What is a species?

A species is a group of organisms that can breed with one another in nature and produce fertile offspring, and are reproductively isolated from other groups. This is the biological species concept of Ernst Mayr. It is the basic unit of classification and of biodiversity counting.

What is the difference between native and alien species?

A native or indigenous species occurs naturally in an area, having evolved or arrived there without human help, while an alien or exotic species has been brought by humans, deliberately or by accident, from another region. Some alien species become invasive and harm native species, like Lantana and water hyacinth in India.

What is the difference between flagship and umbrella species?

A flagship species is a popular, charismatic species such as the tiger used to gain public attention and money for conservation. An umbrella species needs a large habitat, so protecting it also protects many other species living there. A species can be both, as the tiger often is.

What are r-selected and K-selected species?

r-selected species have a high rate of reproduction, mature early, are short-lived and invest little in each offspring, as in insects and rodents, and do well in changing conditions. K-selected species reproduce slowly, live long and care for few young, as in elephants and whales, and live near the carrying capacity of their habitat.

What is a cosmopolitan species?

A cosmopolitan species is one with a very wide distribution, found in most parts of the world or in many different habitats. Examples are the house sparrow, the common crow, the peregrine falcon and humans. Such species usually have a broad tolerance of conditions and use many resources.

PYQ Practice — Statement Analysis

1 The Nilgiri tahr is an endemic species of the Western Ghats.

True

Found nowhere else.

2 A flagship species is always a keystone species.

False

The roles differ.

3 K-selected species produce many offspring with little care.