EXTINCT SPECIES ON THE EARTH

Extinction is the process of evolution that leads to the dissappearence of a population or species.”

When a species becomes extinct, all its genetic heritage is lost. The species evolve into new species in order to adapt to the environmental changes or changes in the genetic heritage.Over 99% of all the species that once lived on the Earth amounting to over five billion species are estimated to be extinct. As per the estimations on the number of current species, a range from 10 -14 million, of which more than 1.2 million have been studied and more than 86% have not yet been discovered.This could happen naturally due to a change in the climate or because of human activities like overhunting or due to the destruction of habitat.

Despite the uncertainties, extinction has three major elements:

  1. For species collectively, extinction is a probability if the killing stress is so rare beyond their experience and therefore outside the reach of natural selection.
  2. The mass extinctions would pave way for the major restructuring of the biosphere where a few successful groups are eliminated allowing minor groups to expand.
  3. In a few cases, there is evidence that extinction is selectively argued by Darwin. It has been made impossible to predict which species are going to be the next victim of an extinction event

1.THE DODO:

The Dodo was a flightless bird native to Mauritius whose population began dwindling and eventually became extinct over the short course of a century when sailors began arriving on the East African island nation.The last of the Dodos were seen in the 1660s and because there really wasn’t an emphasis on specimen preservation, many of the remaining fossils were lost or destroyed.

Even though the Dodo went extinct more than 150 years ago, their story is important. People didn’t believe that God would take away a creature’s existence after having gone through the trouble of creating them, so no one was truly alarmed at their disappearance. This led people to believe that there were more Dodos tucked away somewhere in nature and so, specimens weren’t handled as carefully as they should have been.In fact, Dodo specimen damage and loss was common in 17th and 18th centuries.

Cause of Extinction:

popular belief has sailors hunting and eating the Dodo to the point of extinction, but it’s more likely that the rats (and other animals) the sailors brought with them caused the Dodo’s decline. The BBC reports that rats likely ate dodo eggs and other animals outcompeted the bird for food sources.

2.SCHOMBURGSK’S DEER:

Schomburgk’s deer was native to Thailand and was named after German-born explorer, Sir Robert H. Schomburgk, who was knighted in 1844.Some scientists believe that there may still be a few of these deer in the wild even though they were officially declared extinct in 2006 with the last known deer reportedly killed in captivity in 1938.

Cause of Extinction:

Besides humans, Schomburgk’s deer were hunted by native tigers and leopards. Today, we only know of one mounted deer head which resides in Paris’ Muséum National d’Histoire Natural.

SUMATRAN RHINO:

The last Sumatran rhino in Malaysia passed away in November, 2019, making the extremely rare species locally extinct. The rhino was named Iman and she died due to cancer.The death of Iman made the species critically endangered, with less than 80 Sumatran rhinos left all over the world, primarily in Indonesia. Currently, Sumatran rhinos are the smallest rhino species in the world.

Cause of Extinction:

  • Iman, the last Sumatran rhino left in Malaysia, died over the weekend after a long battle with uterine tumors.
  • The fate of this critically endangered species now lies with a tiny population of no more than 80 individuals in Indonesia, where captive breeding has yielded some success in recent years.

The critically endangered species was decimated by poaching and habitat loss in the past, but today observers say the small and fragmented nature of their populations, and a correspondingly low birthrate, is the biggest threat to their survival. Few of the remaining populations left in the wild are believed to be large enough to support natural reproduction, and isolated individuals have been found to be prone to developing reproductive pathologies like the uterine tumors suffered by Iman(rhino).

INDIAN CHEETAH :

In a report by ANI in September, 2019, it was stated that the Indian Cheetah, along with three other species is now extinct in India due to desertification. The numbers dropped down to 150 and eventually the species died out.This intense desertification was caused due to the excessive use of pesticides and heavy industrialisation in agricultural areas. The report also showed how this desertification had a negative impact on the entire food chain.

Cause of Extinction:

Trapping of large numbers of adult indian cheetah’s, who had already learned hunting skills from wild mothers, for assisting in royal hunts is said to be another major cause of the species rapid decline in india as they never bred in captivity with only one record of a litter ever.The animal is believed to have disappeared from india when Maharaja Ramanuj Pratap Singh Deo of Koriya hunted and shot the last three recorded Asiatic cheetahs in india in 1947. It was declared extinct by the government in 1952.

INDOCHINESE TIGER :

This species was mainly found in southeast Asia before it became critically endangered. Its numbers reduced to 1500 and then eventually the species became extinct.The species is completely extinct in the wild but there are a few tigers that are living in captivity. It is completely wiped out in Cambodia and the largest number of tigers are now residing in Thailand. The main reason for its extinction is hunting and poaching.

According to a lot of media and UN reports, the world is on track to lose two-thirds of its wildlife population by the end of 2020. Even common wildlife species like Koala bears are now prone to extinction because of the Australian bushfires, which happened due to climate change in the area.

Cause of Extinction:

According to the World Wildlife Fund (WWF), indochinese tiger numbers are in shocking decline across its range because of shrinking habitats, expanding human populations, poaching, and illegal wildlife trade. Vital tiger populations are also depleted by a growing commercial demand for wild meat in restaurants

Hunting for trophies, poaching by farmers, and the growing demand for tiger bones in Oriental medicine are key factors for the indochinese tiger decline. Habitat loss due to population growth is also a major concern.It’s believed there are around 350 indochinese tiger leftin the world. This low population is due to poaching and habitat loss.

CATARINA PUPFISH :

Catarina pupfish is a freshwater fish found in Mexico. The species got extinct when their natural habitat got disrupted due to groundwater extraction.The fish was living in the wild till 1994, but due to the rapid loss, the species was moved to captivity. It survived till 2012 and then got completely extinct in 2019.

Cause of Extinction:

The species got extinct when their natural habitat got disrupted due to groundwater extraction. The fish was living in the wild till 1994, but due to the rapid loss, the species was moved to captivity. It survived till 2012 and then got completely extinct in 2019.

Habitat loss caused the extinction of the Catarina pupfish, and it is threatening thousands of species. Humans have modified more than 70% of terrestrial and 60% of marine habitats. The most recent report from the UN estimates that one million animal and plant species are facing extinction in the next few decades as a result of habitat loss and degradation, overexploitation, poaching, climate change, pollution, and invasive species.

PYRENEAN IBEX :

The Pyrenean ibex was a type of goat abundant across the Pyrenees mountains. It declined over two centuries from hunting, disease and inability to compete with other species. The last was a female called Celia, who died in 2000. In a first, it was declared “unextinct”in 2003 when a cloned female ibex was born alive, but died several minutes later from lung defects.The Pyrenean ibex, a subspecies of the Spanish ibex, is one more recently extinct animals.

Cause of Extinction:

The ibex, native to the Pyrenees Mountains on France and Spain’s border, was declared extinct in 2000. During medieval times, the Pyrenean ibex was abundant, but their population decreased due to hunting. 21 years ago this month, a wild goat species went extinct — and kicked off a bizarre but ultimately hopeful scientific adventure. The pyrenean ibex became extinct in January of 2000, when a falling tree landed on the last surviving member of the species.

SPLENDID POISON FROG :

In 2020, the IUCN (International Union for Conservation of Nature) declared that the splendid poison frog was extinct. Sadly, that makes the splendid poison frog one of the most recently extinct animals on the planet.The small red frog, a species of poison dart frog, lived in the neo-tropical forests of Panama in the mountain ranges adjacent to Costa Rica. Common names of the splendid poison frog in Spanish are Rana venenosa and Sapito venenoso

Cause of Extinction:

Deforestation and habitat degradation are the primary threats to the splendid poison frog. Human activities such as logging, expansion of urban and suburban areas, and the construction and use of rail lines have had a significant impact on population numbers.The splendid poison frog or splendid poison-arrow frog (Oophaga speciosa) was a species of poison dart frog  endemic to the eastern end of Cordillera de Talamanca, western Panama.

SPIX’S MACAW:

The Spix’s macaw is a recently extinct animal from near the Rio São Francisco in Bahia, Brazil. In 2019, the bird known as the “Little Blue Macaw” because of its vibrant blue feathers was declared extinct in the wild. Fortunately, experts have documented about 160 Spix’s macaws in captivity. Scientists and the Brazilian government are working on a planned release of the parrots to the wild in 2021.

The species was popularized in 2011 when the animated movie “Rio” depicted a cartoon characterization of the breed. Early scientists named the species for the German naturalist who documented them in 1819.

Cause of Extinction:

Though it perished in 2000, some 60-80 are still being bred in captivity. 5. While they were driven to extinction by human factors like the building of dams and trapping for trade, there is still hope to clone and revive these birds in wild populations.Since the year 2000, the species has been considered extinct in the wild. In addition to illegal trafficking, the destruction of habitat due to human influences was the main reason for the extinction of the species.

Habitat destruction and illegal trapping and trade are what caused the wild Spix’s macaw’s demise.A female spix’s macaw released from captivity at the site in 1995 was killed by collision with a power line after seven weeks. The last wild male disappeared from the site in October 2000; his disappearance was thought to have marked the extinction of this species in the wild.

PASSENGER PIGEON :

Although the passenger pigeon went extinct over 100 years ago, you could say that it is one of the recently extinct animals in relation to the earth’s age. The passenger pigeon’s abundant numbers made the species seem ineradicable, but it became the poster child of animal conservationist groups after its demise. Most ecologists estimate that passenger pigeons numbered in the millions when Europeans began settling North America. Eyewitnesses reported that skies would darken when flocks flew overhead on sunny days.

Cause of Extinction:

Passenger pigeons vanished after farmers cleared their habitat and hunters netted, shot and poisoned them to the point of extinction. The extermination of the passenger pigeon was part of the motivation for the birth of 20th century conservation.  The last known bird died in the Cincinnati Zoo in 1914.People ate passenger pigeon in huge amounts, but they were also killed because they were perceived as a threat to agriculture. As Europeans migrated across North America, they thinned out and eliminated the large forests that the pigeons depended on.The last passenger pigeon died in the Cincinnati Zoo in 1914

THE QUAGGA :

Another of the relatively recently extinct animals is the Quagga. The odd-looking animal resembled a cross between a stout pony and a zebra. With the zebra’s dazzling stripes across its head, mane, and neck, and the chestnut colouring of a pony or horse throughout the rest of its body, the quagga was hunted to extinction in the late 1800s by European settlers.

The somewhat recently extinct animal was native to South Africa and was a subspecies of the plains Zebra. Named by the African tribe of Hottentots for its distinctive ‘kwa-ha-ha’ call,  quagga is an onomatopoeia. The last animal died in the Amsterdam Zoo in 1883.Interestingly, scientists of the Quagga project are using selective breeding of zebras in an attempt to revive the extinct quagga.

Cause of Extinction:

The Quagga’s extinction is generally attributed to the “ruthless hunting”, and even “planned extermination” by colonists. Wild grass eating animals such as the Quagga were perceived by the settlers as competitors for their sheep, goats and other livestock.Quagg’s extinction a Nasty Surprise. 1883: The quagga goes extinct when the last of these South African zebras dies at the Amsterdam Zoo.

MAMMOTH:

Woolly mammoths lived during the last ice age, and they may have died off when the weather became warmer and their food supply changed. Humans may also be partly responsible for their disappearance due to hunting. Although the word “mammoth” has come to mean “huge,” woolly mammoths were probably about the size of africian elephants. Their ears were smaller than those of today’s elephants. This was probably an adaptation to the cold climate that kept their ears closer to their heads and kept them warmer. Their tusks were very long, about 15 feet (5 meters) and were used for fighting and digging in the deep snow. Mammoths were herbivores and ate mostly grass, but also ate other types of plants and flowers.

Cause of Extinction:

Most woolly mammoths went extinct roughly 10,000 years ago amid a warming climate and widespread human hunting.They pinpointed a collection of genetic mutations in the Wrangel Island mammoth and synthesized these genes in the laboratory to test their functionality.While woolly mammoths were once plentiful across the northern hemisphere, they actually went extinct in two separate events. The first wave of mammoth extinction occurred on the heels of the last ice age and global warming led to the loss of their habitat, around 10,500 years ago.

The last woolly mammoths on Earth had disastrous DNA | Live Science
Spix's Macaw in green tree
Splendid Poison Frog

REASONS FOR EXTINCTION OF SPECIES:

The important causes of extinction include:

Asteroid Strikes:

A meteor strike on the Yucatan peninsula in Mexico led to the disappearance of dinosaurs millions of years ago. Most of the mass extinctions, such as KT-extinction or Permian-Triassic extinction were caused due to such events. The astronomers constantly keep an eye on comets or meteors that could lead to the end of human civilization.

Climate Change:

Climate change is yet another factor that could destroy terrestrial organisms. During the end of the last ice-age, most of the megafauna were unable to adapt to the changing warm temperatures. They died due to lack of food and hunting by early humans. Even modern civilization is stepping towards the threat of extinction due to global warming.

Disease:

Various epidemics had been the cause of extinction of a large population of humans and animals on earth. The Black Death wiped out one-third of the European population in the Middle Ages.

Loss of habitat:

Every animal has its own comfort zone where it can breed and raise its young ones. For eg., a bird is comfortable only on the branch of a tree. Due to the expansion of human civilization and industrialization, the forests have been destroyed which are an abode to most of the animals. Due to lack of space and eventually food, the populations of many organisms have been minimised.

Better Adapted Competition:

The better-adapted populations win over the ones that lag behind. For eg., the pre-historic mammals were better adapted than the dinosaurs. The ones which are well-adapted survive, while the others become extinct.

Pollution:

The pollution from the industries and vehicles have led to a drastic change in the oxygen levels in the atmosphere as well as water. This has led to the extinction of most of the aquatic as well as terrestrial species.

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Categories: Science