Category extinction

What is a real life example of extinction?

We are in the middle of a mass extinction brought about by human activity.

What is mass extinction?                       

A vast number of species going extinct at one period in time is called mass extinction. It is also known as a biotic crisis, as it leads to a decline in the world’s biodiversity. In a mass extinction, species disappear faster than they are replaced by new species.

What are the causes of mass extinction?

Earlier extinctions took place due to natural causes like global climate change, fluctuating sea levels and catastrophic events like volcanic eruptions or asteroid impacts. However, the ongoing extinction is the result of human actions.

How many mass extinction events have occurred on the Earth?

The Ordovician-Silurian extinction, 444 million year ago; the Devonian extinction, 360 million years ago; the  Permian extinction, 250 million years ago; the Triassic-Jurassic extinction, 201 million years ago; and the Cretaceous extinction, 65 million years ago. The first eliminated marine invertebrates, the second, tropical marine species. The third and the largest decimated most of the marine species and many terrestrial vertebrates, and the fourth destroyed all the Triassic reptiles. The fifth last was most likely caused by an asteroid hitting the Earth. It killed off dinosaurs of all species, including the remaining non-avian dinosaurs.

Are we facing a sixth mass extinction?

At present, we are in the middle of the sixth mass extinction, the Holocene extinction, which is entirely caused by the humans. It started 10,000 years ago with the beginning of agriculture and industrialization. Human activities like deforestation, climate change, and pollution have been major contributors.

These events wipe out numerous species, reshaping ecosystems and allowing the evolution of new species. They can disrupt habitats, biodiversity, ecological stru and food chains.

What is the impact of mass extinctions?

These events wipe out numerous species, reshaping ecosystems and allowing the evolution of new species. They can disrupt habitats, biodiversity, ecological structure and food chains.

Picture credit: Google

Why are anteaters going extinct?

As their name suggests, giant anteaters are large. Like so many large mammals the world over, these creatures too are facing rising extinction risk, especially in Brazil. What are the reasons for this? Come, let’s find out.

Giant anteaters are native to Central and South America. In 2020, the Pantanal region of South America witnessed fires that destroyed about a third of the area. It proved to be injurious or fatal for wildlife such as jaguars inhabiting the region. According to a report, the fires killed “an estimated 17 million animals”. The numbers are not available for those injured or displaced. But among those that suffered are giant anteaters. Apparently, “more than 50 giant anteaters injured or displaced by the Pantanal fires were taken in by state rescue projects – a leap from 13 the previous year”. In 2021, Pantanal witnessed fires again, though on a scale smaller than the previous year. However, reports suggest that a few areas from 2020 suffered in 2021 too – this could spell disaster for the species there since they’d be denied time for recovery. Several animals are also indirectly affected by such fires. For instance, young animals could be orphaned and ones trying to escape such fires could get involved in accidents or end up in the hands of poachers. As for giant anteaters, some tried to escape the fire in 2021 and got hit by cars; they were rescued.

But, fires are not the only reason for falling giant anteater populations. A report says “Brazil’s anteater populations have fallen 30% over 26 years”. As solitary creatures, they require a large range for habitation. But this is becoming more and more difficult due to land seizures, expansion of farming, ranching, and mining “in the Amazon and the Brazilian savanna”. Further, the animal also has “a low population growth rate due to its life history of long gestation periods and single offspring”.

The giant anteater plays a significant role as both predator and prey. While it is consumed by jaguars and pumas, the mammal consumes large quantities of insects, especially ants and termites. Given this interconnectedness, the extinction of this insectivore can have unimaginable impacts on its ecological range.

Fires are not the only reason for falling giant anteater populations. As solitary creatures, they require a large range for habitation. But this is becoming more and more difficult due to land seizures, expansion of farming, ranching, and mining “in the Amazon and the Brazilian savanna”. Further, the animal also has “a low population growth rate due to its life history of long gestation periods and single offspring”.

Picture Credit : Google 

Is our world undergoing the sixth mass extinction?

There’s proof we are increasingly losing species, and this is not good for us humans

What is mass extinction?

To be classified as a mass extinction, at least 75 % of all the species on Earth must go extinct within a short geological period of less than 2.8 million years. That timeframe seems long to us because modern humans have only existed for about 2,00,000 years so far.

Mass extinction is not new

Extinctions and speciations (species evolving over time) do not happen at uniform rates through time; instead, they tend to occur in large pulses interspersed by long periods of relative stability. These extinction pulses are what scientists refer to as mass extinction events. The Cambrian explosion was a burst of speciation some 540 million years ago. Since then, at least five mass extinction events have been identified in the fossil record (and probably scores of smaller ones). Arguably the most infamous of these was when a giant asteroid smashed into Earth about 66 million years ago in what is now the Gulf of Mexico. The collision vapourised species immediately within the blast zone. Species were killed off later by resultant climate change and volcanic activity too.

Are humans responsible for the current crisis?

Humans have been implicated in smaller extinction events going back to the late Pleistocene (around 50,000 years ago) to the early Holocene (around 12.000 years ago) when most of the megafauna, such as woolly mammoths, giant sloths. diprotodons, and cave bears, disappeared from nearly every continent over a few thousand years. Much later, the expansion of European colonists throughout the world from about the 14th Century precipitated an extinction cascade first on islands, and then to areas of continental mainland as the drive to exploit natural resources accelerated. Over the last 500 hundred years, there have been more than 700 documented extinctions of vertebrates and 600 plant species. These extinctions come nowhere near the 75 % threshold to include the modern era among the previous mass-extinction events. But those are just the extinctions humans have recorded. In fact. many species go extinct before they are even discovered- perhaps as many as 25 % of total extinctions are never noticed by humans. But it’s not the total number of extinctions we should focus on; rather, it’s the extinction rate. Even the most conservative estimates place the modern era well within the expected range to qualify as a mass extinction. If the current rate of extinction continues we could lose most species by 2200.

When species disappear

One may think that so long as the species that provide resources for modern societies survive, there’s no reason to consider extinction a problem. The evidence suggests otherwise. Species loss also erodes the services biodiversity provides us. These include reduced carbon removal from atmosphere (which climate change), reduced pollination and increased soil degradation that compromise our food production, poorer water and air quality, more frequent and intense flooding and fires, and poorer human health. Even human diseases such as HIV/ AIDS, Ebola, and COVID-19 are the result of our collective indifference to the integrity of natural ecosystems.

There’s still hope

We could potentially limit the damage if societies around the globe embraced certain fundamental, yet achievable, changes. We could abolish the goal of continuous economic growth, and force companies to restore the environment. We could limit undue corporate influence on political decision-making. Educating and empowering women would also help stem environmental destruction.

Did you know?

  • In the timeline of fossil evidence going right back to the first inkling of any life on Earth- over 3.5 billion years ago – almost 99 % of all species that have ever existed are now extinct. That means that as species evolve over time, they replace other species that go extinct.
  • When the giant asteroid hit our planet, about 76 % of all species around at the time went extinct, of which the disappearance of the dinosaurs is most well-known. But dinosaurs didn’t disappear altogether-the survivors just evolved into birds.

Picture Credit : Google 

Do penguins face threat of extinction?

As much as 98% of colonies of this penguin species is at risk of extinction by 2100. So, the U.S. has listed the bird as “threatened” under the Endangered Species Act. There’s still hope to save them.

Where do emperor penguins live?

Different species of penguins are found in different parts of the Southern Hemisphere. The emperor penguins are found only in Antarctica, where they live and breed. Emperor penguins thrive on Antarctica’s coastlines in icy conditions any human would find extreme. The penguins breed on fast ice, which is sea ice attached to land But they hunt for food within the pack ice-sea ice floes that move with the wind or ocean currents and may merge. Sea ice is also important for resting, during their annual moult, and to escape from predators.  

The U.S. lists them as “threatened”.

If current global warming trends and government policies continue, Antarctica’s sea ice will decline at a rate that would dramatically reduce emperor penguin numbers to the point that 98% of all their colonies would become quasi-extinct by 2100, with little chance of recovering, a new study has shown. That’s why the U.S. Fish and Wildlife Service finalised a rule listing the emperor penguin as “threatened” under the Endangered Species Act, effective November 25, 2022. The director of the service said the listing “reflects the growing extinction crisis”. The U.S. Endangered Species Act has been used before to protect other species that are primarily at risk from climate change, including the polar bear, ringed seal, and several species of coral, which are all listed as threatened.

But, these penguins don’t even live in the U.S.!

Sure, these penguins don’t live on US. territory, so some of the Endangered Species Act’s measures meant to protect species habitats and prevent hunting them don’t directly apply. Being listed under the Endangered Species Act could still bring benefits, though. It could provide a way to reduce harm from U.S. fishing fleets that might operate in the region. And, with expected actions from the current administration, the listing could eventually pressure U.S. agencies to take actions to limit greenhouse gas emissions. However, the Bureau of Land Management has never acknowledged that emissions from oil and gas extraction on public lands and waters could harm climate-imperiled species. It issued more than 3.500 oil and gas drilling permits in New Mexico and Wyoming on public land during the first 16 months of the Joe Biden administration.

What’s harming the birds?

The greatest threat emperor penguins face is climate change. It will disrupt the sea ice cover they rely on unless governments adopt policies that reduce the greenhouse gases driving global warming. If there’s too much sea ice, trips to bring food from the ocean become long and arduous, and their chicks may starve. With too little sea ice, the chicks are at risk of drowning. Climate change is now putting that delicate balance and potentially the entire species at risk. Emperor penguins are adapted to their current environment, but the species has not evolved to survive the rapid effects of climate change that threaten to reshape its world. Major environmental shifts, such as the late formation and early loss of sea ice on which colonies are located, are already raising the risk.

How can we save them?

Decades of data since the 1960s are now helping scientists gauge the effects of anthropogenic climate change on the penguins, their sea ice habitat and their food sources. Meeting the Paris Agreement goal could still save the penguins. The results of the new study showed that if the world meets the Paris climate agreement targets, keeping warming to under 1.5 degrees Celsius (2.7 F) compared with pre-industrial temperatures, it could protect sufficient habitat to halt the emperor penguins decline. But the world isn’t on track to meet the Paris Agreement goals. The future of emperor penguins, and much of life on Earth, including humanity, ultimately depends upon the decisions made today.

Picture Credit : Google 

Why are dugongs extinct in China?

A gentle giant, the dugong is functionally extinct in China. Dugong, a gentle marine mammal related to the manatees that lived in China’s southern waters for hundreds of years, has been declared functionally extinct – so few in number that it cannot recover – in the country.

Weighing almost half a tonne, the ocean’s most gentle giant is the only vegetarian marine mammal. Its diet consists mostly of seagrass. Despite having an appearance similar to the manatee, it is different due to its dolphin fluke-like tail and gentle disposition. Some people believe that it inspired ancient tales of mermaids and sirens.

Commonly known as “sea cows”, dugongs are usually found in the coastal waters from East Africa to Vanuatu and even Japan. They are found in 37 more tropical regions in the world, especially in the shallow coastal waters of the Indian and western Pacific Oceans.

The creature is listed as vulnerable in the International Union for Conservation of Nature Red List.

According to research by the Zoological Society of London and the Chinese Academy of Sciences, fishing, ship strikes, and human-caused habitat loss have resulted in the rapid decrease in the number of dugongs since the 1970s.

The mammal had been sought by hunters in the 20th Century for its meat, skin, and  bones. With a significant decline in the population, the mammal has been declared a Grade 1 National Key Protected Animal since 1988 by the Chinese State Council. There has been no verified dugong sightings by scientists since 2000.

The research was done by a team of international scientists who conducted interviews in 66 fishing communities across four Chinese provinces along the coastal region of the South China Sea.

Fishing, ship strikes, and human-caused habitat loss have resulted in the rapid decrease in the number of dugongs since the 1970s.

Picture Credit : Google 

ACCORDING TO INTERNATIONAL UNION FOR CONSERVATION OF NATURE ,WHICH WILDLIFE SPECIES IS FACING EXTINCTION IN INDIA?

The International Union for Conservation of Nature says these wildlife species found in India are facing an extremely high risk of extinction in the wild.

FEW LEFT: The Gundia frog (Indirana gundia) is a resident of a patch of forest in the Western Ghats. As forests are cut down to make way for construction, this frog is slowly losing its home.

DOWNWARD SPIRAL: The population of red-headed vultures has decreased by over 90% in just 10 years. Most of the birds died after feeding on the carcasses of livestock treated with diclofenac, a non-steroid painkiller used by farmers and veterinarians.

POSITIVE NOTE: The gharial (Gavialis gangeticus) was once found across Bangladesh, Bhutan, India, Myanmar, Nepal and Pakistan. It currently survives in several severely fragmented populations in India and Nepal. Conservation programmes in India are slowly improving numbers.

DEEP TROUBLE: The Indian swellshark (Cephaloscyllium silasi) is found in the western Indian Ocean. Their numbers are falling due to overfishing.

LOST RODENT: Sightings of the Large Rock Rat, also known as the Elvira Rat, are so rare that there are few photographs of them. This is an illustration of the species (Cremnomys elvira) by the Zoological Survey of India.

Picture Credit : Google