Species can disappear. Why should we care? – The science of yarn


A model of a fossil of a giant-toothed platypus from the Riversleigh Fossil Fields, at an aquarium in Queensland, Australia. Photo: David Clode/Unsplash

  • Some think that we shouldn’t worry too much about species extinction, because extinctions are part of the long process of evolution.
  • The sixth mass extinction is different, however, because it forces the natural world to adapt much faster than it has been able to – or die out.
  • Nor is the extinction of a species a singular event: it always has a cascade of consequences, and man is part of this cascade.

Cochin: Species are created, they sometimes give birth to others, and finally they disappear. That’s evolution at work, and it’s been happening for millions of years.

About 66 million years ago, an asteroid hit Earth and caused the extinction of the dinosaurs, probably helped by a wave of volcanic eruptions around the planet.

When the dinosaurs died out, they left behind many ecosystems without predators and many more without prey. Surviving birds and animals rushed to fill these ecological voids.

The first mammals already existed at the time of the dinosaurs, and the asteroid affected them too. But without the dinosaurs in the picture, the mammals probably had more opportunities to do well and to diversify.

Species are disappearing all the time, and the ecosystems they once inhabited are adapting to their disappearance. So why is the current wave of species extinction so significant? Won’t the natural world just adapt? Why should we care?

Reason 1: We are causing and accelerating extinction

The bramble cay melomys (Melomys rubicola) was declared extinct in 2016. Photo: Ian Bell, EHP/State of Queensland

The pace of evolution is moderated by natural changes, which are rarely rapid or overwhelming. But human activities are now forcing species to adapt too quickly to evolution – or go extinct. This sixth mass extinction event is unlike anything Earth has experienced before.

In 2019, the IPBES Global Assessment Report on Biodiversity and Ecosystem Services stated that around one million plant and animal species are now threatened with extinction – the most threatened at any given time in the world. history of mankind.

WWF’s Living Planet Report 2020 says wildlife populations around the world are “in freefall”. She estimated that populations of mammals, birds, fish, amphibians and reptiles had fallen by an average of 68% since 1970.

We are changing the environment so much and so fast that we are accelerating extinction.

Some activities directly affect the ability of species to survive, such as logging, poaching, fishing and mining. India’s Asiatic cheetahs were “hunted and captured indiscriminately in the 1700s and 1800s until the day there was not a single one left”, according to conservationist Raza Kazmi.

Our other mode of impact is indirect, through climate change. More greenhouse gases in the atmosphere are warming the surface, forcing entire interconnected ecosystems to suddenly adapt to higher temperatures – and their effects on soil composition, bacteria, plant growth, cycles life of animals and birds, weather conditions, etc.

Many tree species move to northern latitudes in pursuit of colder climates. Himalayan birds fly higher in search of nesting sites. Some crops are expected to be plagued by more fungal diseases. Polar bears may not exist in the wild by 2100. They are part of our heritage.

Reason 2: Extinctions cause more extinctions

A black francolin, the state bird of Haryana. These birds have been reported nesting higher in the Himalayas as the region warms. Photo: Shashank.shekhar29/Wikimedia Commons, CC BY-SA 4.0

The natural world is interconnected. Consequences for a species have cascading effects. Scientists have studied the status of terrestrial vertebrates in 2020 and found that 515 species are on the brink of extinction. And as they got closer to that fate, the fate of the other species they interacted with changed as well.

An endangered species of migratory bat pollinates a species of agave – plants in the asparagus family, some species of which are used to produce tequila – during their annual migration from central Mexico to the southern United States.

Climate change could, however, reduce the overlap in the distribution of agave plants and these bats by 75%. If the bats disappear, the plants will no longer be able to reproduce, which will also put them in danger.

We also don’t know how many species there are, which means we don’t know how deadly these stunts can be. According to studies from 2013 and 2016, there are at least 5 million and up to 1 trillion species on Earth. We have only described about 1.5 million so far.

And on December 9, 2021, the IUCN Red List had assessed the conservation status of only 7% of the 2.13 million species described so far.

Reason 3: We need the species

The Parambikulam forest in Kerala is part of the Western Ghats.  dotcompals/Flickr, CC BY 2.0
Part of the Western Ghats. dotcompals/Flickr, CC BY 2.0

Simply put, we are part of the ecological waterfall.

Protecting a species means protecting its natural habitats. This is the most effective way to mitigate climate change because conserving these habitats – by preventing deforestation, wetland encroachment and reef destruction – allows them to store more carbon in several ways.

Locking more carbon into these natural systems is one of the best ways to offset our reckless carbon emissions.

Species, and biodiversity more broadly, support and maintain many life forms on Earth, including humans. They provide many ecosystem services – like pollinating our crops, absorbing excess rainwater, inducing winds that clean up pollution, creating deltas that support large-scale agriculture, and more. – which we simply cannot live without.

They are linked to our economic growth.

So, although we take it for granted, biodiversity is crucial both for us and for our descendants.


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