Understanding Extinction of Species

Understanding Extinction of Species

Extinction of Species

Extinction is a natural process. Species have disappeared, and new ones have evolved to take their place over the long geological history of the Earth.

There are two major ways of the extinction process—

1. Natural/Background Extinction

• With the change in environmental conditions, some species disappear and others, which are more adapted to the changed conditions, take their place.

• This loss of species, which occurred in the geological past, at a very slow rate, is called natural or background extinction.

2. Anthropogenic/Man-made Extinction

• An increasing number of species are disappearing from the face of the earth due to human activities.

• This man-made mass extinction represents a very severe depletion of biodiversity, particularly because it is occurring within a short period.

• The World Conservation Monitoring Centre has recorded that 384 plant species (mostly flowering plants) and 533 animal species (mostly vertebrates) have become extinct since the year 1600.

• The Earth may lose up to 50% of its species by the end of the 21st century if the current rate of loss continues.

Susceptibility to Extinction

Susceptibility means the state of being susceptible (easily submittable). The characteristics of species particularly susceptible to extinction are:

• Large body size (Bengal tiger, lion, and elephant)

• Small population size and low productivity rate (Blue whale and Giant panda)

• Feeding at high trophic levels in the food chain (Bengal tiger and Bald eagle)

• Fixed migratory routes and habitat (Blue whale and Whooping crane)

• Localized and narrow range of distribution (Woodland caribou)

Many island species also make the species susceptible to extinction.

Baseline Data on Biodiversity

Red Data Book

• The World Conservation Union—WCN (Formerly known as the International Union for the Conservation of Nature and Natural Resources—IUCN) initiated a Red Data Book in 1963, and since then it has been updated frequently.

• The 2012 Red List is the most comprehensive inventory of the global conservation status of plant and animal species.

Blue Book

• The United Nations Environment Programme—UNEP has compiled data on endangered species of the world in the Blue Book.

Green Book

• The Botanical Survey of India—BSI published a Green Book, which lists rare plants growing in protected areas like botanical gardens.

The IUCN Red List/Red Data Book

The IUCN Red List is a catalogue of taxa that are facing the risk of extinction. It is important to understand that the Red List aims to impart information about the urgency and scale of the conservation problem to the public and policymakers.

Uses of the Red Lists

The uses of the Red List are—

1. Developing awareness about the importance of threatened biodiversity

2. Identification and documentation of endangered species

3. Providing a global index of the decline of biodiversity

4. Defining conservation priorities at the local level and guiding conservation action

The IUCN has recognised five (from 1963-99), after that eight (in 2000), and at last nine Red List categories in 2012 for species.

The IUCN Red List Categories

Threatened Species of India

Rare Species

• Species that are at present neither vulnerable nor endangered but are at risk are called rare.

• The species that have small populations in the world and are confined to limited areas or thinly distributed over a wider area.

Example: Asiatic pheasants, Satyr tragopan, Temminck's tragopan

Threatened Species

• Species that are under the threat of extinction and whose survival is unlikely if the causal factors, like habitat loss, continue operating.

• Threatened species include three categories: Critically Endangered, Endangered & Vulnerable.

Vulnerable Species

• Species whose population has not been reduced but faces the threat of extinction, as the causal factors like reduction in habitat can be easily observed.

Example: Black buck, Spotted deer, Golden langur, Asiatic wild ass, etc.

Other Examples of Threatened Species in India

A particular species is considered extinct when its last surviving member dies and has not been seen in the wild for the last 50 years.

Example: Dodo, Passenger pigeon

Critically Endangered Species

• Sumatran Rhinoceros (Himalaya in N-E India & Bhutan)

• Himalayan Brown or Red Bear

• Kondana Soft-furred Rat (Singhgarh plateau near Pune)

• Elvira Rat or Large Rock Rat (Kurumbapatti, Salem district, Tamil Nadu)

• Namdapha Flying Squirrel (Namdapha National Park, Arunachal Pradesh)

• Malabar Large-spotted Civet (Western Ghats)

Endangered Species

• Asiatic Wild Dog/Dhole (Western & Eastern Ghats, Central Indian highlands, West Bengal, Assam, Arunachal Pradesh)

• Brow-antlered Deer/Eld's Deer & Thamin (Keibul Lamjao National Park, Manipur)

• Golden Langur (moist evergreen & moist deciduous forests)

• Indian Hog deer (Northern & North-Eastern India)

• Lion-tailed Macaque (Western Ghats)

• Nilgiri Tahr (Western Ghats)

Vulnerable Species

• Greater one-horned Rhino (Northern India)

• Sloth Bear (Northern India)

• Nilgiri Langur (Western Ghats)

• Binturong (Sikkim)

• Capped Langur (A.P., N-E India)

• Cheetah (Central India)

• Clouded Leopard (Himalayan foothill)

• Dugong / Sea cow (Laccadives, Andaman & Nicobar)

• Four-horned Antelope (Himalayan foothill & peninsular India)

• India Gaur (Mainland)

• Sambar (India)

Lack of Even a Vulture Makes a Big Difference

Interconnectedness of Nature

• A simple rule to remember is that everything in this world is connected with everything else.

• A tiny act of one could have unexpected effects on another.

• What happened to vultures in India is a sample example in this regard.

Decline in Vulture Population

• In the early 1990s, there were approximately.

• 80 million vultures in India and Pakistan.

• But within a decade, the number of vultures declined by 97-99%.

Cause of Vulture Deaths

• After examining hundreds of dead birds, it was discovered that vultures were dying of kidney failure.

• This kidney failure happened due to the drug diclofenac.

• The vultures were eating a dead cow, and the cow had been given a low-cost painkiller, diclofenac.

• It turned out that even a little amount of diclofenac was deadly to vultures.

Slow Breeding Rate of Vultures

• As we know that the vulture is the most efficient scavenger in the world, but it is also a very slow breeder; it lays only one egg in a year.

• Thus, the breeding could not match the speed with which the vultures were dying.

Consequences of Vulture Dying

• When the vulture population declined, dogs started consuming the dead cow, and their population exploded.

• Dogs also picked up the rabies virus from the cows and transmitted them to other dogs.

• Rabid dogs started biting people, and India ended up having the highest rate of human rabies in the world, resulting in approximately. 35,000 deaths a year.

• The vultures, with their strong stomach acid and high body temperature, can destroy corpse pathogens like the rabies virus. Like vultures, dogs do not have such a capacity, so they get caught in rabies and transmit it to others.

Rise in Leopard Population

• The growing dog population was easy prey for the leopard, which began entering the habitat of dogs to hunt them.

• As a result, the leopard population increased dramatically.

• There were more man-leopard encounters, and many more people were killed.

Cultural Impact on Parsis

• The way in Gaya, it's hard to get crows for pind daan to the pind daani; like that, the Parsis faced the problem of finding vultures.

• The Parsis had a tradition to leave their dead for vultures to consume, and now it’s hard to find vultures to carry out the task.

Ban on Diclofenac and Conservation Efforts

• That's why, in 2006, India, Pakistan, and Nepal banned the use of diclofenac for cows and other cattle.

• Meanwhile, vulture conservation centres were also established.

• To date, there are 9 vulture conservation and breeding centres in India.

Slight Recovery in Population

• As a result, the vulture population in India has increased slightly.

In this way, the lack of even a vulture makes a big difference in the ecosystem.

Final Thoughts

Extinction of species is not just a loss of wildlife—it’s a threat to the balance of life on Earth. While natural extinction has shaped evolution for millions of years, the rapid man-made extinction crisis is alarming. Factors like habitat destruction, climate change, illegal hunting, and pollution are pushing countless species towards the brink.

Every vanished species weakens the ecosystem’s resilience and disrupts food chains. The IUCN Red List serves as a critical warning system, guiding urgent conservation efforts.

Protecting vulnerable and endangered species is not merely an environmental issue—it’s a survival necessity for humanity. By supporting conservation initiatives, enforcing wildlife laws, and raising awareness, we can still reverse biodiversity loss.

The fate of Earth’s species is a shared responsibility, and our actions today will decide tomorrow’s living world.