Earth’s Extinction Crisis is Getting Worse and a Million Species are on the Brink

Nature is in crisis, and it's only getting worse. As species vanish at a rate not seen in 10 million years, more than 1 million species are currently on the brink.Humans are

driving this extinction crisis through activities that take over animal habitats, pollute nature and fuel global warming, scientists say. A new global deal to protect nature agreed

on Dec. 19 has the potential to help, and scientists are urging the world's nations to ensure the deal is a success.When an animal species is lost, a whole set of characteristics

disappears along with it – genes, behaviours, activities and interactions with other plants and animals that may have taken thousands or millions – even billions – of years

to evolve.Whatever role that species played within an ecosystem is lost too, whether that's pollinating certain plants, churning nutrients in soil, fertilizing forests or keeping

other animal populations in check, among other things. If that function was crucial to the health of an ecosystem, the animals' disappearance can cause a landscape to

transform.Lose too many species and the results could be catastrophic, leading an entire system to collapse.GONE FOREVERIn the last five centuries, hundreds of unique animals have

vanished across the world, such as the flightless Dodo bird killed off from the island of Mauritius in the late 1600s.In many cases, humans were to blame - first by fishing or

hunting, as was the case with South Africa's zebra subspecies Quagga hunted to its end in the late 19th century - and more recently through activities that pollute, disrupt or take

over wild habitats.Before a species goes extinct, it may already be considered "functionally extinct" – with not enough individuals left to ensure the species survives. More

recent extinctions have allowed humans to interact with some species' last known individuals, known as "endlings". When they go, that's the end of those evolutionary lines – as

occurred in these iconic cases:"Toughie" was the last known individual of the Rabb's Fringe-Limbed tree frog. All but a few dozen of his species had been wiped out by chytrid

fungus in the wild in Panama. In his enclosure at the Atlanta Botanical Garden, he was calling out in vain for a mate that didn't exist. He died in 2016.The story of passenger

pigeon "Martha" is a cautionary tale for conservation: in the 1850s there were still millions of passenger pigeons, but they were eventually hunted to extinction as conservation

measures were taken only after the species was past the point of no return. Martha, the last, died in 1914 at the Cincinnati Zoo."Lonesome George", found in 1971, was Ecuador's